Nutritional Preparation for Athletic Performance

This topic is designed to fully inform you about the evidence-based nutritional approaches used to maximise sport and exercise performance. This is another area of nutrition that is rife with misinformation, half-truths, and recommendations given without full context. In order to give quality information to clients around what they should be eating to maximise performance, a trainer must have a full understanding of how the body utilises fuel during different forms of exercise, the energy requirements of different forms of exercise and the type and timing of fuel ingestion that will optimise performance. That is exactly the information you will learn in this topic.

Of utmost importance during this learning process is your ability to separate what we learn about performance-based nutrition from other nutrition-assisted goals (e.g. weight-loss or body composition improvement). These are often diametrically opposing approaches, although something that many clients seek. Just like expecting someone to train for a marathon and a strength competition simultaneously leads to suboptimal progress in both areas, optimizing nutrition for peak performance while aiming to reduce weight can also yield less-than-ideal results. When one goal calls for higher energy intake to meet performance demands, and the other necessitates calorie restriction for improved body composition, we need to find a balance that works best for your client.

Eating for performance is actually a very simple construct to understand. To give your clients the opportunity to perform at their best you need to ensure they do the following:

1. Match total energy requirements:
   Ensuring you consume enough calories to support your activity level prevents chronic fatigue, aids in recovery, and reduces the risk of injury.
2. Fuel appropriately for activity (before and during):
   Prioritise intake of the right types and amounts of nutrients to match the energy demands of your exercise session.
3. Prevent gastrointestinal discomfort:
   Choose foods and fluids that won't cause discomfort during exercise, ensuring optimal performance.
4. Maintain optimal hydration:
   Staying adequately hydrated before and during exercise is crucial.
5. Prioritise post-exercise recovery:
   Incorporate periods of rest and consume foods that aid in recovery, preparing you for optimal performance in subsequent sessions.

This means that nutrition for physical performance encompasses more than simply eating well before exercise. This topic will work through each of the key nutritional factors outlined above, discussing the latest evidence-based thinking in each of these areas so you are better equipped to advise your clients. Please remember, that this entire topic is focused on performance-based nutrition and that this sometimes includes suggestions that fall outside of eating guidelines for the general population. While most general population members who play a sport or go to the gym regularly will also benefit from the information discussed in this module, the concepts we cover are primarily aimed at performance athletes. Most general population members will be best served following general MoH guidelines, while athletes looking to maximise their performance will benefit from a more individualised approach.

Let’s take a look at the following areas of nutrition preparation for athletic performance.

1. Fuel utilisation basics – how the body uses fuel during different types of exercise and how we can use this to understand the food we need to consume in the pre-exercise period.
2. Energy balance
   How to calculate the energy needs of individuals on a daily basis to match the energy requirements of the training they do.
3. Nutrition strategies pre-exercise
   Amounts, timings and type of food to consume based on the type, duration and intensity of exercise that will be performed.
4. Nutrition strategies during exercise
   Who needs to worry about this, what, when and how to consume it.
5. Nutrition strategies post-exercise
   Amounts, timings and types of food to consume for different times of the day.
6. Specific nutrition considerations for:
   • Resistance training
   • Endurance training and competition
   • Ultra-endurance events
   • Intermittent sports – including tournament eating approaches.

The total amount of calories you need to consume, along with the amount and type of food you eat in the pre-exercise and post-exercise timeframes, will be highly dependent on the type of exercise you are performing. For example, the nutritional requirements of someone going on a 20-minute walk are very different from those of someone who is preparing to run a marathon, play a game of netball, or perform a 90-minute weight session.

This topic will cover specific nutritional strategies tailored for various training objectives. The core principle underlying all that you'll learn here is the need for personalised nutrition in athletic performance. This personalisation extends not only to the athletes themselves but also to the specific exercise they undertake on a given day or in a particular session

Knowing how to advise clients on what to eat for their performance requires an in-depth knowledge of how a body utilises fuel during different types of exercise.

Knowing the type of fuels that are used during different forms of activity is vital to understanding the type of fuel that needs to be provided to the body prior to exercise to achieve optimal performance. For example, noting that a game of basketball uses primarily carbohydrates would suggest that eating a pre-game meal high in fat and protein and low in carbohydrates would not prepare the athlete for optimal performance.

In general, the higher the intensity of an activity, the more carbohydrates will be used as fuel (provided carbohydrates have been eaten). Lower intensities of exercise allow greater use of the aerobic energy system which can utilise fat as a fuel source also, but this doesn’t diminish the need for carbohydrate fuelling as these types of activities often last for longer durations. Here is an example to illustrate this. The graph below shows the relative fuel provision of carbohydrates and fat during two different intensities of running over the same time period.

Of course, it is not a surprise that running at a 70% of VO2 Max intensity for 20 minutes will burn more total calories than walking at 50% of VO2 Max. What is interesting though is that running not only burned more calories, but provision of fuel from both carbohydrate and fat were higher than compared with walking. While the percentage of fuel utilised as fat was 50% of total energy use during walking, the number of calories burned from fat was actually higher while running even though the requirement for fuel from carbohydrate rose significantly.

Therefore, the source of fuel used during an activity is only part of the equation. How many calories of each macronutrient are used during the different activities is also important when considering fuelling requirements. For example, one 200m hurdles race would burn less than 10 calories, almost all of them derived from carbohydrates. One hour’s hard cycling could burn up to 1000 calories. While a sprint burns a higher percentage of carbohydrates as a fuel source than cycling, an hour's cycling will burn far more calories than carbohydrate and therefore require considerably more fuelling pre-exercise.

It would seem that intensity not only plays a role in which macronutrient is used during activity but also in how many total calories your client expends (even over shorter periods of time). As the video mentions, this is because higher-intensity efforts utilise less efficient energy pathways and therefore burn more fuel.

Let’s gain an understanding of the role of carbohydrates and fat in higher-intensity exercise. Mul et al (2015) suggest this is because the rate of ATP synthesis from carbohydrates is two times faster than from fatty acids. This means that when the body is put under pressure to produce fuel for working muscles, it will choose the fuel that is easiest (and fastest) to convert to ATP. Mul et al (2015) examined the utilisation of macronutrient fuel sources during different intensities of exercise and found that both carbohydrate and fat oxidation rates increased proportionally as exercise intensity increased up to a workload of 55% of maximum effort. However, as exercise intensity was increased up to a workload of 75% of maximum effort glucose metabolism markedly increased while fat oxidation rates markedly decreased.

Mul et al (2015) found that this had nothing to do with the availability of fatty acids to be used in the muscle but was more likely due to the effects of rising muscle acidity levels and the presence of other substrates needed for fast fat oxidisation. Regardless of the reason, at intensities over 70% of maximum effort, carbohydrate is the preferred source of energy for muscles.

This information is valuable because it alerts us to the importance of eating carbohydrates in the pre-exercise period if we intend to exercise at meaningful intensities over 70% of maximal effort. This is to ensure our working muscles have enough easy-to-oxidise fuel available for the duration of the workout or performance. This is where we need to isolate our thinking to performance outcomes. Yes, teaching (or forcing) the body to utilise more fat as a fuel has benefits if your client has a weight loss goal and maybe even for events that require extremely long durations at low intensities, but for exercise performance at higher intensities (i.e. all performance sports), carbohydrates are a vital part of a pre-exercise nutrition plan.

Examining why low carbohydrate diets are recommended

It's important to note that different dietary approaches cater to specific goals and lifestyles. Low carbohydrate diets, for instance, may have their merits for certain objectives, but they might not align with the needs of athletes engaged in high-intensity, prolonged exercise.

Optimising athletic performance

The simplest way to optimise performance, from a nutritional perspective, is to match the energy demands of the exercise session with the correct amount and type of energy supply. It makes complete sense. If there isn't enough energy available to perform a particular activity, then the ability to perform that activity at its best is reduced.

The energy requirements of a given sport or bout of exercise are ultimately determined by the duration and intensity of the activity. That’s why it is very difficult to give a blanket nutrition for exercise approach that suits all athletes for all sessions. The amount and timing of food intake in preparation for an activity will vary considerably depending on what activities are planned. For example, going for a 30-minute jog at relatively low intensity could be done with or without fuelling with no apparent performance decrement. This is because the body will use stored energy to fuel the run. However, a hard 90-minute cycle will definitely benefit from the ingestion of fuel in the hours preceding the activity.

Ensure that your clients are consuming sufficient nutrients to support their performance. Athletes have elevated energy requirements due to their training regimen. Meeting these increased needs is a crucial aspect of an athletic diet, and neglecting to do so over prolonged periods can have detrimental effects on both health and performance. (Australian Institute of Sport (AIS) Nutrition Resources, n.d.).

Energy availability

Unfortunately, athletes get their nutritional advice from a range of sources (some not very reputable) which means despite the hours of training they put into trying to achieve their performance goals, many are simply not providing their bodies with the fuel required to perform at their peak. This may stem from a lack of knowledge, poor advice, or a desire to improve body aesthetics over performance. This issue is more than not simply eating enough pre-exercise (although that is part of it). Instead, it is most often a result of a lack of daily calorie consumption for overall dietary (and physical activity needs). The key cause of this appears to be that many athletes do not adjust their dietary intakes considerably for different training days, despite some days having extremely high energy expenditure vs. others.

Signs of under-fuelling

Watching out for the early signs and symptoms of under-fuelling can help identify the issue early and help avoid the potential adverse impact on both health and performance. The Australian Institute of Sport (AIS) produced a handy questionnaire for their athletes so they could monitor themselves for potential under-fuelling. Research performed by the AIS suggested that female athletes were more likely to be under-fuelling than males with up to 75% of female athletes in their programmes potentially under-fuelling and 1 in 3 having more than 2 of the following under-fuelling symptoms (from the questionnaire):

• Low mood/feeling irritable
• Low motivation towards training
• Persistent fatigue
• Unintentional weight loss
• New or persistent gut discomfort
• Loss of appetite (or always feeling hungry)
• Menstrual cycle changes
• Lowered sex drive
• More frequent injury/illness
• Longer rehabilitation timelines
• Poor performance or lack of adaptation from training.

Variations in energy demands across different activities

Recognising this key fact is the first step in understanding that the way your client eats as an athlete should change on a daily basis depending on the amount and type of exercise that is to be performed.

How many of your clients would eat the same amount and type of food before a session of exercise or sport, regardless of the duration or intensity of the session to come?

Some movements have more caloric costs than others. For example, an activity that uses most of the muscles in the body, like running, will have a higher caloric cost than one that uses a few muscle groups (e.g. cycling). Some activities last a long time, but have lower intensities associated with them, while others are shorter in duration but more intense.

Introducing METs

MET stands for the Metabolic Equivalent of Task. One MET is the amount of energy used while sitting quietly. Physical activities can be rated using METs to indicate their intensity. The MET’s value of a given exercise or activity can then be used to estimate calorie requirements for the activity. This can be a useful tool when working out the ballpark calorie requirements for an individual for both a session of exercise and for total daily caloric needs. Let’s take a closer look at how we can use METs in this way.

One MET is the equivalent of a VO2 measure (oxygen consumption) of 3.5ml of oxygen per kg of body weight per minute (3.5ml/kg/min). 1 MET is thought to be aligned with the oxygen of an individual at rest. Knowing this information, scientists were then able to work out the MET equivalents of a range of different activities using the oxygen consumption (VO2) that occurs during them. This can then be used to calculate the number of calories likely to be burned during each activity.

METs for different activities

A number of databases exist that list the suggested MET equivalents for a range of different activities. The following link lists over 800 activities. Those most relevant to performance come under “sports” or “conditioning exercises” in the table.

MET values for 800 activities

Here are a few examples from the table. The number of METs associated with each activity is listed on the right.

Activity	Specific Motion	MET Value
Conditioning exercise	Elliptical trainer, moderate effort	5
Conditioning exercise	Resistance training (weight lifting, powerlifting, body building), vigorous effort	6
Conditioning exercise	Resistance (weight) training, squats, slow or explosive effort	5
Conditioning exercise	Resistance (weight) training, multiple exercises, 8-15 repetitions at varied resistance	3.5
Conditioning exercise	Health club exercise, general	5.5

As you can see, heavy resistance training is rated as 6 METs, while endurance resistance training (8-15 reps) is rated as 3.5 METs. This means that heavy resistance training consumes 6 times more O2 (and therefore calories) than quiet sitting and endurance resistance training about 3.5 times. When we observe the METs associated with running in the following table, it quickly becomes clear that cardiovascular training modes like running have considerably more energy cost than resistance training sessions (per minute of exercise). For example, running at a 14km/hr pace is rated as 23 METs.

Activity	Specific Motion	MET Value
running	running, 8 mph (7.5 min/mile)	11.8
running	running, 8.6 mph (7 min/mile)	12.3
running	running, 9 mph (6.5 min/mile)	12.8
running	running, 10 mph (6 min/mile)	14.5
running	running, 11 mph (5.5 min/mile)	16
running	running, 12 mph (5 min/mile)	19
running	running, 13 mph (4.6 min/mile)	19.8
running	running, 14 mph (4.3 min/mile)	23

Calculating the Caloric Cost of Activity Using METs

Once you have determined the METs associated with a given exercise activity, you can use this in an equation to estimate the calorie requirement of a particular duration of the exercise for your client. According to Kaminski (n.d.) in an article published by the National Association of Sports Medicine, the calculation you can determine the estimated calories expended during an activity using the following equation.

Note: Perform the equation from left to right.

METs (from the table) x 3.5 x bodyweight (kg) / 200 x minutes of exercise =

While these equations are useful to help determine calorie expenditure for different activities, they are just estimates. The exact calories you burn throughout the day (and during activity) vary considerably depending on gender, age, height, weight, training age and lean body mass. They are also dependent on an individual’s ability to gauge exercise intensity. That said, this is still a useful tool to show how the calorie expenditure (and therefore calorie requirements) for different exercise sessions differ and reemphasises the need to adjust calorie intake daily to match the amount of activity performed.

While the information we have just covered is a helpful way to find activities that burn the most calories for weight loss, the aim of its use with performance athletes is to ensure they are consuming enough calories to meet their daily health and performance needs. By knowing the energy cost of the sessions, they perform, athletes can determine how much (and when) they need to eat from both a daily perspective, and prior to a session.

If a particular session has high-calorie expenditure, then it may require the consumption of two high carbohydrate intakes in the hours prior, versus a lower calorie workout that may only require a modest carbohydrate snack a couple of hours before to meet the needs of the session. In essence, this approach helps to take the guesswork out of nutritional preparation and better ensures that athletes enter each session with enough fuel on board to perform optimally.

Calculating daily calorie requirements

Surveys show that many athletes eat a similar number of calories each day regardless of the amount of training they do. This just doesn’t make sense. A training day with two sessions included will obviously require more calories than a training day with one session. Completing a very prolonged session, will obviously require more calories than a short session.

Matching the pre-exercise intake to the session to come is the first step in achieving energy balance, but there is a bigger picture to consider here too. While the METs equation is great for estimating calorie requirements for different sessions, matching total calorie expenditure across the day is also vital to ensuring we avoid the risk of chronic underconsumption. Chronic deficits in calorie consumption will often result in impaired recovery, reduced performance, and higher risk of injury (Thomas, Burke and Erdman, 2016)

The METs equation can also be used to help estimate daily requirements for energy. To do this you need to refer to the Total Daily Energy Expenditure (TDEE).

Total Daily Energy Expenditure (TDEE)

TDEE is essentially the combined sum of all the ways the body expends energy across a day. It includes the following four expenditure measures:

1. Basal Metabolic Rate (BMR)
   The calories expended if a person were to do nothing but rest for 24 hours. It represents the minimum amount of energy needed to keep the body functioning, e.g., breathing, heart beating, nutrient processing, and cell production. In other words, the amount of energy the body needs to maintain homeostasis. It is roughly 70% of total daily energy expenditure. BMR takes into account height, weight, age and sex and can be calculated using the following equation:

   Female	BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) - (4.7 x age in years)
   Male	BMR = 66 + (13.7 x weight in kg) + (5 x height in cm) - (6.8 x age in years)

2. Non-Exercise Activity Thermogenesis (NEAT)
   Non-Exercise Activity Thermogenesis (NEAT) refers to the calories burned through daily activities that are not structured exercise or physical activity. This encompasses all the movements and tasks performed in daily lives, such as walking, standing, fidgeting, household chores, and any other physical activities that are not part of a planned exercise routine. It accounts for around 15% of TDEE in most people.
3. Thermic effect of food (TEF)
   This is the energy required to digest the food eaten. TEF accounts for between 5-10% of TDEE.
4. Exercise Activity Thermogenesis (EAT)
   This is the burned calories during planned exercise. This is where our METs equation can be used to better determine energy needs of more active people.

TDEE is often estimated, along with broad exercise ranges, using the Harris-Benedict equation. This calculation incorporates all of the expenditure measures discussed above in its estimation.

Activity	TDEE (calories)
Sedentary (little or no exercise)	BMR x 1.2
Lightly active (light exercise/sports 1-3 days a week)	BMR x 1.375
Moderately active (moderate exercise/sports 3-5 days a week)	BMR x 1.55
Very active (hard exercise/sports 6-7 days a week)	BMR x 1.725
Extra active (very hard exercise/sports and a physical job)	BMR x 1.9

While this is a useful estimation tool, it does not account for daily fluctuations in energy requirements based on actual activity performed on a given day. Instead, it gives an average estimate of daily energy needs across a week (regardless of activity performed on a given day). While the total calorie provision of this approach may come close to average weekly calorie needs, it is likely that athletes who follow this equation will undereat on some days and overeat on others. This may help them avoid chronic underconsumption but will not maximise training performance or recovery (adaptation) from individual sessions.

Case Study: Marcus

Let’s look at a comparison of calculation methods for total calorie requirement.

The following case study example looks at how the different calculation methods might affect how well an athlete matches their daily calorie requirements.

Marcus is a 22-year-old representative-level basketball player. He is 88kg and 1.94cm tall. Marcus has provided his training schedule for the week below. It is clear to see that Marcus front-loads his training in the early part of the week and then tapers somewhat into his important game on Saturday.

Time	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
AM	Heavyweights 60 mins	Shooting practice – 45 mins	Power and plyo training - 40 mins	Shooting practice – 45 mins	Stretching and mobility session 30 mins	REST	REST
PM	Court training 90 mins	Club game 90 minutes	Court training 90 mins	Skills and tactics session 60 mins	REST	REP game 90 minutes	REST

Using the Harris-Benedict Equation to estimate Marcus’s TDEE, he would rate as “Very Active” as he trains or plays 6 days a week (often twice a day). Most of Marcus’s training is also quite intense. This means the calculation we would use to work out his TDEE would be BMR x 1.725.

Marcus’s BMR: 66 + (13.7 x 88kg) + (5 x 194cm) - (6.8 x 22 years) = BMR of 2092 calories

Marcus’s TDEE: 2092 x 1.725 = 3609 cal per day

Using this equation, we learn that (on average) Marcus needs around 3600 calories a day. But how can that be right when he does two training sessions on some days and only one (or none) on others? The Harris-Benedict equation does not allow for daily fluctuations in training. It simply averages out the calorie requirements across a week and applies the same calorie value to each day to achieve this. While this approach may be fine for someone who goes to the gym daily, it is not the best approach for an athlete with a full and periodised training schedule.

Using the METs equation we can work out Marcus’s daily calorie requirement based on the actual training he does on a given day. Here is what his Monday would look like:

Monday: Heavyweights (60 minutes): 6 (METs) x 3.5 x 88(kg) / 200 x 60 minutes = 554 Calories.

Basketball training (90 minutes): 9.3 (METs) x 3.5 x 88(kg) /200 x 90 minutes = 1289 Calories

EAT Total Calories = 1843 Calories.

Now remember, these are only the calories he needs to consume to match his exercise output for this day. He still needs calories to match his BMR, NEAT and TEF needs. When we add this 1843 calories to his BMR (2092 calories) we are already up to 3935 Calories. Then we add his estimated NEAT calories (15% of the total calorie figure) and TEF calories (5-10% of the total calorie figure). This equates to an additional 787 calories bringing the total calorie requirement for Monday to 4722 calories.

This figure is 1113 calories more than the average daily calories the Harris-Benedict equation suggests and would place Marcus at a substantial calorie deficit after the first day of training. Here is how things would look after one full week of training:

Day	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
TDEE Estimation using Harris-Benedict Equation	3609 cal	3609 cal	3609 cal	3609 cal	3609 cal	3609 cal	3609 cal
TDEE Using METs estimation process	BMR - 2092 Weights – 554 Practice – 1289 TEF – 197 NEAT – 590 Total: 4722 cal	BMR - 2092 Shooting - 312 Game – 1109 TEF – 176 NEAT – 527 Total: 4216 cal	BMR - 2092 Power – 308 Practice – 1289 TEF – 185 NEAT – 553 Total: 4427 cal	BMR - 2092 Shooting – 312 Skills – 554 TEF – 148 NEAT – 444 Total: 3550 cal	BMR - 2092 Stretching -106 TEF – 110 NEAT – 330 Total: 2638 cal	BMR - 2092 Game - 1109 TEF – 160 NEAT – 480 Total: 3841	BMR - 2092 TEF – 105 NEAT – 314 Total: 2511
Deficit/Surplus if following Harris-Benedict Equation	-1113 cal	-607 cal	-818 cal	+ 59 cal	+971 cal	- 232 cal	+1098 cal

As you can see in the table, the first three days would incur a substantial calorie deficit for Marcus. These are his high-volume training days with two training sessions daily (the days where he needs more calories). While Thursday and Saturday are fairly well matched in terms of calorie requirements, Friday and Saturday actually result in a substantial calorie surplus. Overall, following the Harris-Benedict Equation would result in a 642-calorie deficit in energy across the training week, which is not especially bad at 92 a day, however on the days that Marcus has two meaningful sessions he is considerably short on calories which will begin to affect his performance output, especially as these days are consecutive in nature.

While the Harris-Benedict Equation is very useful for identifying average daily calorie needs in general, those athletes training multiple times a day, or those that train hard on some days and not on others, should take a more individualised approach to daily calorie needs based on the actual amount of exercise performed.

The calorie calculation methods you may already be familiar with used macronutrient estimation tables for CHO, Daily intakes for a varied demographic of individuals and the amount of grams in fat per body weight.

These calorie calculation methods are on par with the Harris-Benedict Equation as it calculates the average daily calorie requirements but does not account for daily fluctuations in training load. To show how close this method of calculation is to the TDEE method Marcus’s estimated daily average calorie needs have been calculated below.

Marcus completes 11.5 hours of training a week including 2 resistance training sessions. He is happy to maintain his current weight.

Carbohydrates – 6.5g x 88kg = 572g x 4 = 2288 cal (64%)

Protein – 1.3g x 88kg = 114g x 4 = 548 cal (15%). Note protein figure has been chosen based on 2 resistance training sessions a week alongside cardiovascular training.

Fat – 1g x 88 = 88g x 9 = 792 cal (22%)

Total calories = 3538 cal

As you can see, this compares fairly well with the 3609 calorie figure the TDEE Harris-Benedict equation suggests.

You have now been introduced to three different calorie expenditure calculation methods. Each of them has their place. If you are simply wanting to calculate a ballpark daily calorie needs value for a client to compare against their actual intakes (e.g. a 24-hour recall or multi-day diet log), then the TDEE and daily intake table calculation methods are great tools. The daily intake table calculations have the added bonus of telling you how best to distribute the macronutrients across the day (e.g. grams of carbs, fat, and protein). These methods will give you a clear indication of whether an athlete is generally eating enough for the exercise they do.

However, if you are looking to better match daily calorie requirements with the amount of training done each day, then the METs calculation is the better equation to go with. This will ensure an athlete matches their calorie needs on a daily basis rather than across a week, which should lead to optimised fuelling for performance and recovery.

Allocations of macronutrients can be applied after these calculations by applying general macronutrient distribution guidelines of:

Macronutrient	% of Daily Calories	Additional Notes
Carbohydrate	50-65%	Higher end for higher volumes of training. Lower end on days with lower training volumes
Protein	15-20%	Higher end for those doing 4 x resistance training sessions weekly or in very heavy training periods. Can also eat a higher percentage on lower volume training days (to help stay full during reduced calorie days).
Fat	20-25%	Most athletes except ultra-endurance would keep closer to the 20% figure

Why not try the METs equation out for yourself to see how your calorie requirements change for your different training days?

Managing additional calories on high-exercise days

Marcus needed almost 1000 calories above the daily average calorie needs on Mondays due to the training volume he performed on that day. Many athletes want to know how they are supposed to fit these additional calories in!

Remember, the additional calories are there to support the exercise energy needs and additional recovery he will need, so it makes sense that most of these additional calories would be eaten around exercise. Once we establish how many calories an athlete requires to cover their daily living, exercise, and recovery needs, the next step is to ensure exercise performance is optimised by targeting their pre-exercise fuelling and recovery eating. Due to training multiple times a day, athletes like Marcus need to get this right twice a day.

Let’s read about the general recommendations for eating around exercise.

The purpose of nutrition around exercise is to:

• Ensure full muscle glycogen and liver glycogen stores for fueling the exercise to come
• Top up glycogen during prolonged exercise to preserve liver glycogen stores
• Providing adequate nutrition post-training for recovery and repair 
• Ensuring replenishment of muscle and liver glycogen stores for the next session (if another session is to be performed later in the day).

Let’s see what this looks like in terms of the amounts and types of macronutrients we should be consuming in these pre-exercise and post-exercise windows.

Nutrition guidelines pre-exercise

The purpose of pre-exercise nutrition is to fill muscle and liver glycogen stores for the exercise to come. The amount and type of food you eat during this window of time will determine whether you achieve this.

This short video explains what we are trying to achieve in terms of filling our glycogen stores:

The importance of carbohydrates in the pre-exercise window

The key component of a pre-exercise eating plan (for performance) is carbohydrate intake. While protein is a very important macronutrient for many other bodily functions, it is not (and should not) be relied upon for energy during exercise. Eating too much protein in the pre-exercise window will likely limit carbohydrate intake (due to the filling nature of protein).

Fat is used for energy (particularly at lower intensities), but we all have significant stores of fat in our bodies, so we already have plenty on board for an exercise session, negating the need to consume it in the pre-exercise window. Fat also slows down the digestive emptying process and therefore should be kept to a minimum around exercise.

The focus on carbohydrates in the pre-exercise period should be easy to understand. Regardless of an athlete's body fat percentage, they have plenty of fat stored in their body for a given exercise session. We also have plenty of protein in amino acid pools and stored as tissues that we can call on if required (not that this is desirable). In fact, eating appropriate amounts of carbohydrates pre-exercise actively prevents the use of protein as an energy source, so it can be used for what it should be used for (e.g. maintenance and repair of tissues).

Carbohydrates are a depleting source of fuel. According to Bean (2014) we can store around 100g of glycogen in the liver and around 400-500g of glycogen in the muscles. This, however, appears to be dependent on how much muscle mass your client has and their level of training. The more muscle, the greater the ability to store glycogen. Fitter athletes can store up to 25g of glycogen per kilogram of muscle compared to about 15g/kg in untrained populations (Bean, 2014).

Many athletes undereat carbohydrates in favour of higher protein intakes

One of the frustrations of many sports nutritionists working with athletes is that mainstream (and social) media seem to demonize carbohydrates. It is absolutely true that consuming large amounts of highly refined carbohydrates without performing exercise can lead to negative health outcomes and obesity, however, carbohydrates should remain a staple of a high-energy requirement athlete’s diet (Burke, 2017).

Burke et al (2001) suggest many athletes, in particular endurance and female athletes, are not consuming enough carbohydrates daily to optimise their training and performance.

You may be surprised that resistance-trained athletes are not on this list. This is likely not because of being more aware of carbohydrate needs, but because their requirement for carbohydrates is not as great.

Thomas, Burke and Erdman (2016) suggest that a key strategy in promoting optimal performance in competitive events or intense training is matching body carbohydrate stores with the fuel demands of the session. Failure to do this is associated with fatigue and a reduction in the intensity of sustained exercise, while inadequate carbohydrates for the central nervous system impairs performance-influencing factors such as pacing, perceptions of fatigue, motor skill, and concentration.

Choosing an amount of carbohydrate to consume

The amount of carbohydrates consumed by an athlete in the pre-exercise window will depend on their size and the duration and intensity of the exercise to come. Larger athletes competing at high intensities for over an hour should aim for the top end of the 100-200g range in the four hours prior to exercise, while smaller athletes, or those only planning on a short, or low-intensity workout, should eat amounts towards the bottom of this range.

In an article published by the National Academy of Sports Medicine, Murphy (2017) suggests a great way to choose an amount of carbohydrate to ingest based on body size is to aim to eat 2g of carbohydrate for every kilogram of body weight between 2 and 4 hours prior to exercise. This means a 90kg athlete should aim to eat 180g of carbohydrates, while a 50kg athlete could consume 100g.

Athletes often prefer to break their pre-exercise eating into two intakes, one larger meal a few hours from exercise that might also include a small serving of protein and one smaller carbohydrate snack 60-90 minutes prior to exercise that will be primarily moderate to high GI in nature.

Timing

The timing of a pre-workout feed is critical to athlete performance (and comfort) during exercise. Eat the meal too early and the energy is depleted before the exercise session; too late and the stomach will still be digesting the food leading to nausea or discomfort. This is why it is important that athletes (and trainers) understand how different foods behave in the gut, i.e. how long they take to break down and absorb and the effect they have on the system once they enter the bloodstream.

Consuming lower GI carbohydrates a few hours from exercise allows for a gradual release of glucose from the gut and avoids a sharp spike in blood glucose (and the associated insulin spike this creates). This allows glucose to circulate to the muscles along with a small amount of insulin which facilitates the entry of glucose into the muscle for storage.

The following video shows this process in action.

It is important to be aware that many low GI foods are also rich in fibre, and fibre can cause stomach discomfort in the lead-up to the activity. What athletes can tolerate in the lead-up to exercise is highly individual and should be practised in training before trying out in a competition. This is why many athletes choose to consume moderate (more refined) GI carbohydrates alongside a small amount of protein in the lead-up to exercise. Protein slows the absorption of carbohydrates so has a similar effect to fibre (without the gastrointestinal discomfort).

Here is a reminder of some suitable foods to consume 3-4 hours before exercise:

• Crumpets or multi-grain toast with jam or honey
• Baked potato + cottage cheese filling + glass of milk
• Smoothie with fresh fruit, yoghurt and oats.
• Baked beans on toast
• Breakfast cereal with milk (oats, Weet-bix)
• Bread roll with meat/salad filling + banana
• Fruit salad with fruit-flavoured yoghurt
• Pasta or rice with a sauce based on low-fat ingredients (e.g. tomato, vegetables, lean meat).

Here is a reminder of some suitable snacks to eat within 90-minutes of exercise:

• Liquid meal supplement, Up & Go etc.
• Flavoured milk or fruit smoothie
• Sports bars/muesli bars (those with high carbohydrates and limited protein and fat)
• Breakfast cereal with milk (cornflakes, Nutri-grain etc.)
• Fruit-flavoured yoghurt
• Fruit (all, but especially bananas)

Eating high GI foods before exercise: What happens?

Insulin not only facilitates the entry of glucose into the liver and muscle for storage it also pushes glucose into fat cells (particularly when there are excess levels of glucose in the bloodstream).

Eating high-GI foods when there is no active demand for glucose (e.g. in the hours before exercise) leads to a rapid rise in blood sugar. This results in an equally rapid increase in insulin production by the pancreas. The high glucose state in the blood is viewed negatively by the body, so the insulin is produced to quickly clear this excess of glucose. Excess calories are usually sent to fat cells for storage, and this is exactly what happens in this instance. Insulin pushes the excess glucose into cells (many of which are fat cells). Unfortunately, much of the fuel you have eaten with the intention of filling your muscle glycogen stores hasn’t arrived at the intended location!

A secondary issue arising from eating the wrong carbohydrate in the hours before exercise is that as insulin clears the bloodstream of excess glucose quickly, this can often lead to a blood glucose “low” that is often accompanied by hunger and feelings of lethargy, lack of focus and light-headedness. None of these bode well for the exercise session to come.

The following image illustrates the difference in blood glucose clearance rates between the ingestion of lower GI vs higher GI carbohydrates. Note how the ingestion of high GI carbohydrates increases blood glucose quickly and leads to a rapid clearing of excess glucose (by insulin) that leads to low blood glucose just after an hour after consumption. In contrast, low GI carbohydrate empties the gut at a slower rate avoiding a spike in blood glucose and a matching level of insulin production. Blood glucose is allowed to circulate to working muscles where insulin facilitates its entry to be stored as muscle glycogen for later.

Moderate to higher GI foods are best used in shorter timeframes before exercise because we need the blood glucose to exit the gut before the exercise starts (to avoid discomfort). That is why small amounts of higher GI foods are recommended within an hour of exercise as the blood sugar will be in the bloodstream as exercise begins so it can be used for energy rather than stored. This is often the best approach for pre-exercise nutrition when it comes to early morning training as it is unlikely that athletes will get up 3-4 hours prior to eat. In this situation, Murphy (2017) recommends that an athlete try to consume around 1g of carbohydrate per kilogram of bodyweight (or a minimum of 50g) of high to moderate GI carbohydrate one hour before exercise.

Murphy (2017) suggests that anything consumed less than 1 hour before an event or workout should be blended or liquid-based (such as a sports drink or smoothies) to promote rapid stomach emptying. She also warns that athletes should bear in mind that they are all individuals, and that their bodies will absorb and tolerate foods differently. This is why athletes should always experiment with the size, timing and composition of pre-event/activity meals to determine what will be best tolerated before trying anything in a competitive situation.

Dr. Louise Burke (2022) has shown that athletes that may struggle to tolerate carbohydrate intake within an hour of exercise, but this tolerance can be trained through practice to improve both the tolerance to food in the stomach and the speed of absorption of carbohydrates.

Here is a reminder of some suitable snacks to eat within 30-60 minutes of exercise:

• Sports drink
• Carbohydrate gel
• Cordial
• Sports bars
• Jelly lollies.

Gradually raise the glycemic index of foods as exercise approaches. This helps ensure that higher GI foods are consumed closer to activity, allowing for quicker digestion and reducing the risk of undigested food in the gut at the start of the session.

According to Sports Dieticians Australia (SDA) getting your nutrition plans wrong before a training session or event usually means that you don’t optimise your client’s potential during exercise. Failing to fuel or hydrate properly before exercise can result in:

• Earlier onset of fatigue
• Reduced speed, especially during repeat efforts
• Reduced endurance
• Poor concentration and decision-making
• Skill errors
• Gut upset
• Suboptimal body composition.

Nutrition guidelines during exercise

The purpose of consuming calories during exercise is to help preserve body glycogen stores so that they last for the entire exercise session avoiding a reduction in performance.

Refuelling during exercise may be necessary when training or competing continuously for over an hour. High GI carbohydrates should be consumed at a rate of 30-60g per hour after the first hour of exercise. This is in recognition that muscle and liver glycogen stores are likely to have been somewhat depleted after this time and may fully deplete as exercise continues towards the 90-minute mark. The ingestion of more glucose at this point can have a sparing effect on stored glycogen.

To aid fast absorption and avoid gastrointestinal discomfort, this carbohydrate is best consumed in either liquid or gel form. This can be further enhanced with the inclusion of sodium (for reasons discussed in the last topic).

The only other situation where the consumption of carbohydrates during a workout may benefit an athlete is when there is insufficient time to fully optimise muscle glycogen stores. This may be during an early morning workout, or when a very quick turnaround between workouts or games occurs (such as in a tournament situation).

Regarding insulin in this instance, the body has a natural understanding of when glucose is actively needed for energy. In moments of high energy demand, the role of insulin becomes somewhat redundant. This video demonstrates that muscle contraction initiates a process that opens glucose channels in the muscles, irrespective of insulin levels.

Note: The following video explains this process in detail (sciency!) But the end result is the glucose channels are held open allowing circulating glucose to enter freely.

In ultra-endurance events completed over hours at lower intensities athletes are recommended to ingest some solid food in order to minimise hunger symptoms and gastrointestinal distress that can be caused by high levels of simple glucose ingestion. Other research indicates that gastrointestinal distress can largely be avoided if multiple carbohydrate sources that have different routes and rates of absorption are used. Dr. Louise Burke (2022) suggests combining glucose and fructose forms of carbohydrates for more complete absorption. Most commercial sports drinks contain a mix of these.

Here is a reminder of suitable items to consume during the exercise of over 90-minutes duration:

• Sports drinks 
• Sports gels
• Fruit juice or soft drinks
• Sports bars or muesli bars
• Bananas
• Confectionary.

It is important to note that these approaches are only really necessary for advanced exercisers who are able to maintain high levels of exercise output for long periods of time.

As the duration of the exercise increases there may be more opportunity for inclusion of solid carbohydrate foods, as well as foods containing a little protein and sodium (to replace losses). The consumption of these foods should be practised during training before they are tried in competition.

Nutrition guidelines post-exercise

The purpose of post-exercise nutrition is to stimulate protein synthesis for repair and recovery and to replenish glycogen stores for the next session of exercise. This means post-workout intakes should include protein and carbohydrates and fat should be kept to a minimum (as it can slow the absorption process).

Full recovery requires the right nutrients, fluids electrolytes and adequate rest. This improves performance in the next session and reduces the chance of injury. Getting recovery nutrition right is especially important during periods of heavy training and any time two or more sessions happen within a 12-hour period (Murphy, 2017).

Intense training depletes muscle glycogen. The first 30-60 minutes after an exercise session provides an enhanced opportunity for nutritional recovery due to factors like increased blood flow and insulin sensitivity. This creates a state that boosts cellular uptake and glycogen replenishment (Rosenbloom & Coleman, 2012).

After exercise, the restoration of muscle glycogen occurs in two phases. During the first phase, glycogen synthesis is rapid and does not rely on insulin. This phase lasts around 30-40 minutes and is the reason why carbohydrates are best consumed quickly after exercise. The second phase of glycogen restoration occurs at a slower rate and does depend on insulin. This requires additional carbohydrate intake at regular intervals across waking hours (Murray and Rosenbloom (2018).

Thomas, Burke and Erdman (2016) along with Murphy (2017) suggest athletes replenish glycogen stores by consuming 1-1.2g of carbohydrate per kilogram of body weight within 30 minutes of completing training. If the training is completed early in the day and there is more training to come, this should be followed up by ingesting further carbohydrate-rich snacks 2-4 hours later. If no further exercise is planned for the day, then normal eating patterns can resume. Some athletes will forgo large intakes of carbohydrates post-training for training that finishes late in the day or evening. This is fine provided there is ample time to replenish carbohydrate stores fully prior to the next training session. This approach is not recommended, however, when there is an early training session planned for the next morning.

In terms of the GI of the post-event meal, any GI is ok as there is a demand for glucose in the muscle (to replace what was used in the session) and insulin sensitivity is enhanced post-training. This carbohydrate can be consumed alongside protein (and may even enhance protein uptake by muscle), but fat levels should be kept to a minimum so that digestion and absorption is maximised.

Protein should also be included in the post-exercise meal. Thomas, Burke and Erdman (2016) reported that laboratory studies show that muscle protein synthesis (MPS) is optimised in response to exercise by the consumption of high-quality protein sources providing at least 10g of essential amino acids within a 2-hour period post-training. This translates to a protein intake of 0.25-0.3g/kg of bodyweight or 20-30g of protein across a typical range of athlete body types. Higher doses (e.g. 40g+) have not yet been shown to further enhance MPS and may only be beneficial for the very largest of athletes (Thomas, Burke and Erdman, 2016). Regular protein intakes should then be consumed every 3-5 hours over the course of waking hours to continue to take advantage of elevated post-exercise MPS mechanisms.

Louise Burke (2022) shares some interesting insights about general protein consumption and the way in which protein should be ingested. Her key recommendations include:

• Most people eating Western-style diets eat more than enough protein daily, however, we are not great at eating it across the day, instead eating most of it in one meal at night. This means, that while some athletes may be getting enough total protein in their day, they may not be taking advantage of increased MPS mechanisms across the day.
• We need to consume protein directly after exercise to stimulate muscle re-synthesis. It appears eating a small serving of protein alongside carbohydrates in the post-exercise window can enhance glycogen resynthesis.  Regular top-ups with small intakes of protein (20-25g) every few hours are recommended to continue the rate of MPS.
• All people (but especially athletes with higher total protein requirements) should look for ways to increase protein in meals where they don’t typically eat much (e.g. breakfast) and have more moderate intakes at dinner.
• Increases in MPS have been shown to occur following ingestion of milk products, lean meat and dietary supplements derived from whey, casein, soy and egg. To date, dairy proteins appear to be superior to other tested proteins, largely due to leucine content and the ease of digestion and absorption of amino acids in fluid-based dairy foods.
• When whole food protein sources are unavailable or not convenient, then portable, third-party tested, dietary supplements with high-quality ingredients can serve as practical alternatives to ensure athletes meet protein requirements in a timely manner after exercise.
• In the same way that carbohydrate intake should be adjusted to match daily exercise requirements, protein intakes should also fluctuate. Requirements for protein increase whenever an athlete begins a new form of training, or ramps things up in terms of volume or intensity. Protein needs will decrease when an athlete has settled into a new routine of training.
• In order to get the best out of protein consumed athletes must ensure they eat sufficient carbohydrates to fuel their exercise sessions. This ensures amino acids are spared for MPS rather than being oxidised for energy.

You have now covered the key information related to eating around exercise to optimise exercise performance and recovery. Most of this information is related to the immediate windows of time before and after exercise. The recommendations above are current and will satisfy the requirements of most athletes.

Let's shift our attention to specific nutritional considerations for different types of athletes (i.e. endurance vs. resistance training etc.). Before we do this, we need to take a closer look at glycogen storage, depletion and replenishment, so we can better understand the recommendations to come. In particular, we need to look at the effects of daily training (and multiple training days) on our ability to match our glycogen storage needs for the exercise we do.

Glycogen storage capacity

Humans can store approximately 100g of glycogen in our liver and an average of around 400-500g of glycogen in our muscles, however, the range is actually between 350-700g dependent on muscle mass, body size, gender and training level (Knuiman et al 2015).

This level of glycogen storage suggests that most people can store around 2000 cal of glycogen in their body. This is obviously more than enough for the vast majority of exercise sessions but remember some of this is also needed to fuel the brain and other organs.

So, it appears that if athletes ensure they have full glycogen stores pre-training they should have no problem in supplying enough energy to get through a full session while maintaining optimal intensities. But this is only the case if athletes are fully replenishing glycogen stores following trainings and there is clear evidence that this is not often the case. Murray and Rosenbloom (2018) suggest many athletes do not consume enough dietary carbohydrates to meet current recommendations for the daily carbohydrate intake considered necessary to fully replenish muscle glycogen stores and that this leads to a cumulative reduction in available glycogen for future exercise. These authors believed that this less-than-optimal daily carbohydrate intake is likely a result of demanding training schedules, busy lives, confusion regarding the benefits of dietary carbohydrates, and inadequate understanding of basic sports nutrition concepts.

Glycogen depletion

Glycogen depletion is obviously dependent on the duration and intensity of the exercise you perform. Depletion of full glycogen stores can occur over a few hours of low-intensity exercise, around 80 minutes of constant effort cardio at lactate threshold pace, or in as little as 30 minutes of high-intensity activity. It is also important to note that full glycogen depletion is not required to elicit performance impairment. In fact, impairments to performance can occur far before you empty your glycogen tanks.

Knuiman et al (2015) suggest that there is a critical level of muscle glycogen, below which muscle performance is impaired. This level appears to begin to occur soon after 50% of muscle glycogen depletion has occurred. Murray and Rosenbloom (2016) suggest that a trained well-fed endurance athlete has a typical glycogen store of around 150mmol/kg wet weight and that they may reduce their stores to less than 50mmol/kg of wet weight during a prolonged session of exercise (e.g. 90 minutes running). When muscle glycogen levels fall to below 70mmol/kg of wet weight, calcium release from the sarcoplasmic reticulum is impaired which reduces crossbridge formation and thus impairs muscle contraction. This means most endurance athletes engaged in sessions lasting longer than 90 minutes will likely exhibit performance impairment over the last stages of the activity. It also emphasises the importance of ensuring full glycogen stores at the start of the training session and helps us understand the necessity that these types of athletes consume additional carbohydrates after the first hour of exercise (i.e. to spare muscle glycogen, so this impairment doesn’t occur). But how easy is it to replenish glycogen stores after exercise?

Glycogen replenishment

Full restoration of muscle glycogen takes a lot longer than you might think. It is not simply a case of eating one post-exercise feed containing carbohydrates.

According to Burke et al (2016) an exercise session of around 60 minutes at a moderate intensity will deplete around 50% of muscle glycogen and that this can take between 12 and 15 hours to fully replenish. More substantial glycogen depletion (like that from longer, or high-intensity sessions) can take between 20 and 24 hours to fully replenish.

This makes it likely that many athletes are beginning their next exercise bout with less-than-optimal glycogen stores. The image below shows the cumulative effect of daily training on glycogen levels using the example of an athlete who begins a training week with optimal glycogen levels. You can see that following each session, the athlete was unable to completely restore glycogen levels meaning that they dropped below the critical threshold for muscle impairment in a number of the sessions on later days. You can also see how a full 24 hours of recovery (with associated carbohydrate intake) led to the complete restoration of glycogen stores. This information is critical for athletes and coaches to understand. From a team sport or competitive endurance athlete point of view, it suggests that important high-intensity or volume sessions should be planned earlier in the training week (following a rest day) and that a training taper would be necessary towards the end of the week to allow restoration of muscle glycogen levels before games or competitive events.

Murray and Rosenbloom (2018) have provided a handy set of guidelines for athletes who are involved in repeated days of strenuous, prolonged physical activity and training. These recommendations cover total carbohydrate needs across a day (including pre and post-exercise amounts) and give these athletes the best chance of minimising the cumulative effect of repeated exercise sessions on glycogen storage.

Recommendations for daily carbohydrate intake for athletes involved in repeated days of strenuous, prolonged physical activity and training.

Exercise intecity	Description	Dietary carbohydrates	Comments
Low	Easy activity such as yoga, tai chi, walking, or any exercise done at a light effort (can easily talk or sing during the activity)	3-5 g/kg BW/d	Normal dietary intake is usually sufficient to restore muscle glycogen content
Moderate	One hour or more of activity such as walking, jogging, swimming, or bicycling at a modest effort (can carry on a conversation without problem but cannot sing)	5-7 g/kg BW/d	A diet in which at least 50% of the energy (calories) comes from carbohydrate food is usually sufficient to restore muscle glycogen content
High	one hour or more hard exercise such as interval training running swimming bicycling at a modest effort (can carry on only very brief conversations)	6-10 g/kg BW/d	Postexercise carbohydrate/protein intake with high carbohydrate meals and snacks, is needed to fully restore muscle glycogen within 24-36 h
Very High	Very hard exercise for an hour or more or very prolonged exercise such as interval training, ice hockey, soccer, basketball, running, swimming, bicycling and an intense effort (cannot speak during the effort)	8-12 g/kg BW/d	Postexercise carbohydrate/protein intake with high carbohydrate meals and snacks, is needed to fully restore muscle glycogen within 24-36 h

The recommendations shown in the table highlight the difficulty of replenishing glycogen stores for those athletes performing very hard exercises for an hour or more daily. An 80kg athlete would need to consume 640-960g of dietary carbohydrate a day to replenish glycogen stores and would need 24-36 hours to fully replenish stores. This means full replenishment is unlikely unless a full rest day is taken.

In summary, you should now understand the importance of ensuring optimal stores of glycogen when starting exercise sessions, while also realising that when athletes are training daily (or multiple times a day) it is unlikely that this will always be possible. The previous discussion should also highlight the importance of rest and recovery days.

The next step is to look at specific considerations for different types of athletes. It is pretty obvious that the nutritional requirements for a resistance-trained athlete are likely to be somewhat different to those of a marathon runner or football player given the energy requirement differences that exist within each. The final section of our studies this week will look at the specific considerations we should make for different types of athletes based on the needs of their sport. We will also look at best practice strategies for athletes who need a quick turnaround between sessions or games.

Note: The following nutritional strategies for different sports and activities will focus on carbohydrate and protein consumption. While fat consumption is critical to a balanced diet, it plays no key role in nutrition plans for pre-, during and post-exercise and as such intake of fat should be kept to a minimum around the time of training to avoid gastrointestinal discomfort issues.

For optimising nutrition for athletic performance, it's essential to explore tailored approaches for various types of training. Let’s learn more about specific nutritional considerations for a range of athletic endeavours, including resistance training, endurance activities, ultra-endurance challenges, intermittent sports, and multi-event tournaments. Let's take a closer look at each to ensure your clients are fuelled for success.

Nutrition considerations for resistance training

Carbohydrate

A vast number of studies have proven that carbohydrates enhance performance in endurance sports. There has been far less research into the importance of carbohydrate intake on resistance training performance. This has led to many of these athletes seeking advice from less-than-optimal sources.

The first thing we should always consider when looking at the nutritional requirements for specific training modalities is the energy cost of performing a session of that exercise is. Resistance training is typically characterised by short bursts of near-maximal muscular contractions. When performing resistance exercises, glycogen is crucial to supply energy for these high-intensity muscular efforts (Knuiman et al (2015). This is because muscle contractions during both low-and high-load resistance training rely primarily on the anaerobic glycolysis pathway for energy (Henselmans et al (2022). Therefore, it stands to reason that glycogen depletion could limit resistance training performance. However, due to the work:rest nature of resistance training, total glycogen depletion is actually quite modest during a session.

A single resistance training session typically results in a reduction of muscle glycogen of between 24-40% (Slater and Phillips, 2011). This is supported by Astorino and Kravitz (1999) who reported that 6 sets of leg extensions at 70% of 1RM reduced leg extensor muscle glycogen by 39% and that a group of nine bodybuilders who completed 5 sets each of back squats, and front squats, leg press and leg extensions to fatigue reduced glycogen stores in the key leg muscles by around 30%. The exact reduction in glycogen is determined by the duration, intensity and volume of the exercise bout. The largest glycogen depletion appears to occur during sessions including high repetitions with moderate loads (Knuiman et al, 2015).

The lower glycogen depletion associated with resistance training sessions suggests that carbohydrate intake for these sessions is not as important as for sport or endurance training sessions. Few studies have specifically examined the importance of carbohydrate intake for resistance training. Typical recommendations from these studies suggest a daily intake of between 3-7g of carbohydrates per kilogram of body weight. Slater and Phillips (2011) recommend a moderate 3-5g/kg per day for strength and power athletes and 4-7g/kg per day for bodybuilders. Lambert et al (2004) suggest 5-6g/kg per day (or 55-60% of calorie intake) for bodybuilders. However, evidence does exist to challenge this to suggest that consuming considerably less carbohydrate than this does not impair resistance training performance (Escobar et al, 2016).

Escobar et al (2016) performed a literature review to assess whether the current recommendations for carbohydrate intake for resistance training were reflective of actual need. Here are the main findings from this review:

• The total energy requirements for resistance training sessions are less than for sports and endurance training but experimental evidence has yet to confirm a minimum daily carbohydrate intake for those who only do resistance training. That said, regular resistance training does not appear to lead to significant levels of glycogen depletion, this suggests that even moderate daily intakes of carbohydrates would be enough to replenish stores.
• While very limited studies have shown a reduction in resistance performance with low carbohydrate ingestion, a number of studies have shown that modest (and even minimal) amounts of carbohydrates may maintain resistance training exercise performance. Further to this, data also suggests that hypertrophy, anabolic cell signalling, gene transcription and muscle protein synthesis appear unimpaired by lower carbohydrate consumption.
• Those studies that compared resistance training in a fasted state compared to being fuelled with carbohydrates noted a clear advantage to fuelling before training in terms of muscle power output and repeated strength efforts. Additionally, the presence of muscle glycogen stores prevented the conversion of glucose from protein through gluconeogenesis.
• When no carbohydrate was taken post-exercise, muscle glycogen levels were still somewhat replenished. This was thought to happen due to the conversion of protein stores into glycogen via gluconeogenesis. This was shown to have a negative impact on MPS (growth and repair).
• Replenishment of full glycogen stores should be easily achieved in these athletes with a normal balanced dietary approach. The only time replenishment may become a concern is in the unlikely scenario of exhaustive training bouts on the same muscle groups occurring within 24 hours of each other.
• Based on the limited research currently available and the many limitations observed in the research that does exist, Escobar et al (2016) believe it would be premature to adjust the current recommendations for carbohydrate intake associated with resistance training (i.e. 3-7g/kg per day), but that there was a need for more robust studies to explore the level of need for carbohydrate for this mode of training.

This information was supported by a more recent systematic review by Henselmans et al (2022) who reported that 39 out of 49 studies comparing the effect of high and low carbohydrate intakes on strength training found no significant effects of carbohydrates on performance. The other 10 studies found that carbohydrate intake might enhance strength training performance in specific contexts that included when compared against fasted training, workouts involving 10 or more sets per muscle group and twice-daily workouts.

Taking this information into account, it appears prudent for resistance-based athletes to follow daily carbohydrate intakes of between 3-5g/kg daily. This puts them in the range of low-effort cardio activities, so already appear to recognise the reduced need for carbohydrates by this group of athletes. The low glycogen depletion rate of this form of training also suggests that pre-exercise intakes of carbohydrates should be towards the lower end of pre-exercise guidelines (e.g. 100g in the 4 hours prior) and even less for smaller athletes. Pre-exercise carbohydrate intake is important to avoid the conversion of protein into glucose for energy. Provided the resistance training programme separates the training of the same muscle groups by 24 hours, full muscle glycogen replenishment shouldn’t be an issue. It also appears that a little more carbohydrate may be necessary when performing high-volume resistance training or training twice daily.

Post-resistance training intakes should include carbohydrates to avoid using protein sources to convert into glucose for muscle glycogen replenishment. This can have a negative effect on MPS and recovery.

For sporting athletes that do a combination of cardio, sports-related sessions and resistance training, daily and pre/post exercise intakes of carbohydrate should be adjusted depending on the sessions performed daily, with more carbohydrate eaten on days where cardio and sport is played vs. days where resistance training is done. From a total calorie requirement, days, where resistance training is done in isolation, would require less total calories than days where sport or endurance activities are performed. Using the METs equations will account for these differences as weight training METs are significantly lower than cardio and sport METs. (Note: If using the calorie calculation tables used in level 4 nutrition, there is a provision for reduced carbohydrates in the calculation with the suggestion that the carbohydrate figure be reduced by 1g/kg/day if 50% of training is resistance-based, and 2g/kg/day if almost all training is resistance based.)

Protein

Muscle is primarily composed of protein and water. In order to maintain and improve muscle mass, adequate protein intake is critical. The rates of protein degradation (breakdown) and synthesis (growth) increase in response to high-intensity resistance exercise (Lambert et al, 2004). Obviously, muscle protein breakdown occurs during the exercise session, while protein synthesis rates are significantly increased in the hours after exercise.

Strength-trained athletes have advocated high-protein diets for many years. While the research supports the increased need for protein in resistance training athletes, many athletes consume amounts far exceeding these recommendations in the belief they will elicit additional benefits. This has not been supported by scientific evidence to date. Current guidelines for protein intake supported by the literature recommend that resistance-trained athletes who perform 4 or more sessions of lifting a week should consume twice the dietary protein of the general population. This amounts to 1.6-1.7g per kilogram of body weight per day.

Research clearly indicates that the recent focus on protein ingestion in this athlete population means that the vast majority of these athletes easily exceed these increased requirements. Exceeding the upper range of the recommended protein daily intake offers no additional benefit to MPS over a diet lower in protein (As long as total energy requirements are met). Consuming larger intakes of protein simply promotes increased amino acid use as a fuel (Slater and Phillips, 2011).

A few studies have reported the benefit of higher levels of protein (than current recommendations), however, these studies were usually in the context of calorie-restricted diets and abnormally high volumes of training.

Tagawa et al (2022) performed the most recent meta-analysis on the subject of increased protein intake on strength. This was the first meta-analysis to quantitatively assess the detailed dose-response relationship between total protein intake and muscle strength in both trained and untrained populations. This analysis included 82 randomised controlled trials on the subject. In all experiments, subjects were subjected to traditional resistance training modalities and feed a variety of protein amounts from 0.8g/kg/day to 3.80g/kg/day. The authors of this meta-analysis concluded the following:

• Protein intakes assist significant improvement in muscle strength and mass but only when combined with resistance training.
• Improvements in muscle strength increased proportionally with increased protein intake but only up to 1.5g/kg/day with no additional gains observed in any trials above this amount.

This research clearly suggests that the generally recommended intakes of protein of 1.6-1.7g/kg/day are more than sufficient for protein synthesis requirements in resistance-trained athletes. Eating more than these figures may have benefits when athletes are on a calorie-restricted diet to compensate for conversions of protein into glucose for energy. There is limited evidence that consuming up to 2g/kg/day may be beneficial for those athletes in active growth phases (adolescent athletes) and athletes under unusually high training volumes (e.g. ultra-endurance athletes).

There is also growing evidence that consuming small quantities of protein at regular intervals across waking hours is more beneficial than large intakes post-training and in main meals as is general practice. This is in recognition that enhanced muscle protein synthesis is apparent for up to 24 hours following a session of intense resistance training, with increased sensitivity to the intake of dietary protein during this period (Thomas, Burke and Erdman, 2016). The most common recommendation in the literature is to consume 20-25g (or 0.3g/kg of body weight) of high-quality protein every 3-5 hours across the day.

These authors also suggest that it is probably better to stop categorising athletes as strength, endurance etc., and rather base protein intake on the training they are completing during each micro-cycle. This involves raising protein levels to accommodate increases in training load and intensity and reducing intakes when the initial training change shock has passed.

Another consideration is the training level of athletes. In general, experienced lifters require less total protein intake to maintain and increase strength compared to newer lifters or those entering a new training phase.

Protein: Pre-exercise and during exercise

Recently, there has been more interest in consuming amino acids both before and during resistance training. The thinking behind this is to promote a more anabolic environment that may stimulate muscle protein stimulus and/or reduce muscle damage and protein breakdown during exercise and reduce muscle soreness following exercise. Another school of thought revolves around having freely circulating amino acids in the bloodstream during exercise to reduce the risk of breaking down protein stores for energy.

The results of experiments targeting this approach have suggested that targeted consumption of protein in the pre-exercise window didn’t offer additional advantage over normal pre-exercise eating recommendations (i.e. a mixed meal of carbohydrate and protein a few hours from the start of exercise). There were also concerns that focusing on protein consumption during this window before training may result in less-than-optimal carbohydrate fuelling (Slater and Phillips, 2011). One thing that was observed in studies, was that when insufficient muscle glycogen was present when training began, amino-acid use as a fuel was increased.

All evidence points to the fact that protein ingestion during exercise and during the pre-exercise period seems to have less of an impact on MPS than the post-exercise provision of protein. Limited studies have suggested that consumption of easily absorbed amino acids may have a small enhancement effect on MPS depending on the type of training that takes place. Co-ingestion of protein and carbohydrate during 2 hours of intermittent resistance-type exercise has been shown to stimulate MPS during the exercise period which may in turn limit protein breakdown and may offer benefits that extend into the metabolic adaption window post-training. However, most studies in this area have been focused on ultra–endurance-type exercise bouts rather than normal resistance training approaches (Thomas, Burke and Erdman, 2016).

One line of thinking is that protein ingestion before or during exercise allows post-exercise muscle protein synthesis rates to be elevated more rapidly immediately after exercise because there are greater amounts of amino acid available to the muscle during the early stages of post-exercise recovery (Van Loon, 2014). Schoenfeld et al (2013) dispute this theory on the basis that increases in strength and hypertrophy were unchanged even when protein consumption was withheld for up to 3-hours post training as long as total protein requirements were met. This indicates that having protein available at the muscle cell to start MPS immediately on finishing exercise is not as critical as once thought. What is clear is that more research is required in this area before we can definitively recommend the benefits of protein ingestion during training.

Protein: Post-exercise

While the effect of protein consumption pre-exercise and during exercise is still a matter for debate, there is no question that consuming protein in the post-exercise window has significant benefits for MPS, repair and subsequent strength and hypertrophy improvement. Multiple studies have shown that MPS is optimised in response to exercise by the consumption of high-quality protein providing 10g of essential amino acids (2g Leucine) in the early stages of exercise recovery (0-2hr). This amount of protein translates to 0.25-0.3g of protein per kilogram of body weight or 15-25g to cover a wide range of athlete body sizes (Thomas, Burke and Erdman, 2016).

Higher doses of more than 40g of dietary protein have not been shown to further benefit MPS and may only be suitable for the largest of athletes, or during calorie-restricted diets (Thomas, Burke and Erdman, 2016).

Nutrition considerations for endurance training

Endurance training typically has a higher energy cost than resistance training approaches. This is simply due to the continuous nature and duration of exercise bouts. At the elite level, endurance training is completed for extended durations at high levels of intensity. Evidence is clear that the utilisation of carbohydrates and not fats is crucial to sustaining the exercise intensities observed in elite athletes (Podlogar, 2022). At recreational levels, those performing endurance activities do so at much slower paces and hold lower intensity rates. This means the energy cost of exercise between these two groups will be significantly different and require significantly different fuelling strategies.

While aerobic exercise has the benefit of being able to utilise multiple fuel sources (i.e. carbohydrate, fat and protein) the predominant energy requirement before exercise remains carbohydrates. This recognises that both fat and protein reserves are already to be found in the body, while carbohydrate is an exhaustible commodity.

Carbohydrates

The importance of carbohydrates as a fuel source for exercise and athletic performance is well established. Equally well developed are dietary carbohydrate intake guidelines for endurance athletes seeking to optimise their performance. While these guidelines suggest specific daily intakes for endurance athletes, carbohydrate consumption should be periodised (along with training) to match the energy output of the athlete. This means rather than following a blanket daily consumption guideline, adjustments should be made for different training days to ensure increases and decreases in energy output are mirrored with intake. This recognises that most endurance athletes are not simply repeating the same workout sessions day in and day out, but rather perform a mix of training durations and intensities based on the phase of training they are currently in.

The key considerations for endurance athletes in relation to carbohydrate consumption are:

• Ensuring optimal muscle glycogen stores prior to an exercise bout (or even super-compensating for competitive events) – This encompasses total carbohydrate ingestion and pre-exercise consumption and appears more important for endurance athletes than any other type of athlete due to the prolonged nature of their training.
• Replenishment of muscle glycogen stores before the next bout of exercise – This includes post-exercise consumption and ongoing consumption throughout the day
• Supplementing with energy during longer sessions (over 75 minutes)

Thomas, Burke and Erdman (2016) along with Murray and Rosenbloom (2018) suggest the following current daily carbohydrate intake recommendations for endurance athletes:

Intensity and type of endurance activity	Daily carbohydrate recommendation	Glycogen replenishment comments
Low intensity (e.g. walking daily)	3-5g/kg per day	Normal dietary intakes will be restored over the next 6-12 hours
Moderate intensity (e.g. one hour or more of jogging swimming, cycling etc)	5-7g/kg per day	A diet where at least 50% of total calories come from carbohydrates will restore over the next 12-20 hours
High intensity (e.g. one hour or more of hard exercise – intervals, running, trail running, swimming, cycling etc).	6-10g/kg per day (depending on duration of activity)	Post-exercise carbohydrate-rich meals along with subsequent high-carbohydrate meals and snacks will fully restore within 24-36 hours
Very High Intensity (e.g. very hard exercise for an hour or more, or very prolonged exercise at a more moderate rate – 2.5+ hours)	8-12g/kg per day	Post-exercise carbohydrate-rich meals along with subsequent high-carbohydrate meals and snacks will fully restore within 24-36 hours

This information shows that an endurance athlete should choose from a range of carbohydrate intakes depending on the exercise planned for the day in question. It also shows the importance of recovery after higher intensity (or very prolonged) training as it can take up to 36 hours for muscle glycogen to fully restore.

Carbohydrate pre-exercise

It has been known for decades that pre-exercise carbohydrate stores influence exercise endurance. While starting exercise in a glycogen-depleted state does increase the amount of fat oxidation during exercise, this does not translate to endurance performance gain. Low glycogen availability induces an increase in the systemic release of amino acids while simultaneously increasing fat oxidation, and as a consequence, exercise intensity drops (Knuiman et al, 2015).

A lot of recent interest in endurance circles has focused on the use of low-carbohydrate diets in training. The theory being that if you can teach your body to have a greater reliance on fat as a fuel source, then you will conceivably have a never-ending supply of fuel on board. Here is what the research has to say about this.

To date, few studies have found an improved training-induced performance effect of performing endurance exercise bouts with low glycogen rather than full glycogen stores. Those that have suggested training adaptations (aerobic capacity) were greater following periods of endurance training with low glycogen stores than with full stores. However, these individual adaptations have not been shown to translate to performance improvements in real-world environments. Knuiman et al (2015) believe this is because of limitations in the studies such as the use of well-trained subjects in experiments who have more metabolic flexibility than lesser-trained people due to a better ability to use fat as an energy source. There were also issues with the way improvements were conducted and measured. For example, multiple studies allowed subjects to self-choose exercise intensities and improvements were measured with tests like isolated knee-extensor exercises that have little relevance to an athlete’s performance in real-life sports events (Knuiman et al, 2015).

To summarise, although a few studies have shown that repetitive low-glycogen training can lead to improved markers of performance in well-trained athletes, the models used in these studies do not accurately reflect an athlete’s performance in real life. Additionally, in real-world settings endurance, athletes use a range of training intensities and progressive overload rather than a fixed sub-maximal intensity across all trainings (as was used in these studies). Finally, chronic use of exercise sessions completed in a low glycogen state has been shown to increase the risk of overtraining syndrome along with negative effects on mood and training motivation, which ultimately lead to reduced training capacity (Achten et al, 2004).

Early morning session considerations

It is often overlooked that if competition or training is to be performed in the morning after an overnight fast, or any period of prolonged fasting, liver glycogen stores may be compromised as liver glycogen is used to fuel body maintenance overnight. This means in the morning, an athlete’s liver glycogen can be substantially depleted (Podlogar and Wallis, 2022). Contrary to this, muscle glycogen stores are typically not affected by an overnight fasting period provided glycogen replenishment was achieved the previous night.

Numerous endurance training and competitions are performed in the morning, so it is important that the meals or snacks eaten after the overnight fast are designed so that there is a focus on liver glycogen repletion. It has been suggested that this can be achieved by providing athletes with a mix of different types of monosaccharides. This suggestion is based on previous observations that combining glucose-based carbohydrates with either fructose or galactose offers benefits on liver glycogen synthesis over glucose-based carbohydrates only. A recent study found improved exercise capacity with a breakfast consisting of fructose-glucose-based carbohydrates as compared to glucose-based carbohydrates only (Podlogar and Wallis, 2022). This means a liquid source like an Up and Go, a smoothie containing milk and fruit may be the best approach for early morning fuel consumption.

Carbohydrate loading

Due to the vast number of studies that demonstrate the importance of muscle glycogen availability for endurance performance, strategies for maximising muscle glycogen synthesis in the days leading up to competition events have been explored. This is known as carbohydrate loading. Carbohydrate loading is not simply eating increased levels of carbohydrates in the days leading up to an event. Instead, it involves the systematic depletion of glycogen stores over a few days (via reduced carbohydrate diets and exercise) followed by a very high carbohydrate intake (10-12g/kg/day) over the last 36-48 hours before an event (although Thoman, Burke and Erdman (2016) suggest well-trained athletes with greater muscle glycogen storage capacity may be able to achieve this super-compensation simply by tapering training and eating the amount of carbohydrate suggested above). Carbohydrate loading can result in up to 25% more muscle glycogen being stored (Murray and Rosenbloom, 2018). Interestingly, this approach does not appear to have an effect on liver glycogen stores.

While short, high-intensity exercise also significantly depletes muscle glycogen, the evidence that carbohydrate loading could assist this type of exercise is not as conclusive, so at present, this strategy is currently only recommended for endurance events of over 90 minutes duration. Athletes should also practice this super-compensation strategy as the additional glycogen storage causes water retention and thus increases an athlete’s mass which could hinder performance through reductions in exercise economy (Podlogar and Wallis, 2022). It should be noted however that these impairments should only have a negative impact early in the performance as the additional carbohydrate and water will be utilised as the event continues.

Carbohydrate during exercise

It is now well established that carbohydrate intake during longer forms of exercise improves performance outcomes. There are currently two ways in which carbohydrate ingestion during exercise has been shown to aid endurance performance. The first is that carbohydrates can be sensed in the mouth causing an activation of certain brain regions, leading to stimulation of the CNS. This has been shown in studies that use mouth rinsing with a glucose solution (Carter et al, 2004). Secondly, and most importantly, additional carbohydrates consumed during exercise are able to maintain a stable blood glucose level providing fuel to working muscles and maybe even sparing liver glycogen stores (although this is yet to be proven definitively).

It appears that an exercising body can process around 60g of rapidly absorbed carbohydrates such as glucose and glucose/fructose mixes (the ideal ratio for a glucose/fructose mix is 2:1). Galactose (in milk) has not traditionally been used in this context due to the belief it is not as readily absorbed, but recent research is suggesting that moderate doses of glucose and lactose combined (48g/hr) can be absorbed just as quickly as a glucose/fructose mix provided fat content is kept low (Odell et al, 2020).

For training and events over 2.5 hours, glucose/fructose mix is recommended at a higher rate of 90g/hr. The best way to achieve this is by consuming a solution with both glucose and fructose. Glucose has a typical absorption rate of 60g/hr, while fructose is thought to absorb through a different pathway at a rate of 30g/hr. This is as high as current recommendations go as it is believed that more carbohydrate than this offers no additional benefit (although current research suggests some athletes (elite cyclists) are reporting consuming up to 120g/hr.

Note: All intake of carbohydrates is best taken in fluid form during exercise as this aids absorption and also helps meet hydration needs (Podlogar and Wallis, 2022).

Carbohydrate post-exercise

The main aim of carbohydrate intake following a bout of endurance exercise is to replenish glycogen liver and muscle glycogen stores for the next bout of exercise. The ability to achieve this depends on the time available before the next bout of exercise. Podlogar and Wallis (2022) suggest it takes between 24-36 hours for full muscle glycogen replenishment to occur following a bout of intense endurance training, whereas liver glycogen is typically replenished after 11-25 hours. This means that if another bout of intense exercise is planned within these time frames, it is likely that athletes will enter the subsequent training session with less-than-optimal stores. In this scenario, athletes should plan for an earlier intake of carbohydrates during the next session to compensate.

Post-exercise recommendations for carbohydrate intakes for endurance athletes are essentially the same as for the general training population, i.e. 1-1.2g/kg within the first 4 hours but ideally as soon after exercise as possible. More recently, research is starting to indicate that highly trained athletes with enhanced glycogen storage capacity, may benefit from consumptions as high as 1.8g/kg in this window of time (Betts and Williams, 2023), however, more research is needed to confirm this. This should be followed up with continued consumption of carbohydrates at a rate based on total carbohydrate needs (between 5-12g/kg/day depending on intensity and volume of training to come).

As mentioned earlier a combination of glucose and fructose appears best as it absorbs through different pathways and allows more complete restoration of both liver and muscle glycogen. New research is also exploring the use of galactose into post-workout intakes to see if this offers any further enhancement of glycogen replenishment. Early indications suggest it might. The image below shows the effect of different carbohydrate types on the rapid replenishment of glycogen and supports the ingestion of a combination of sugars.

Protein

Endurance athletes require higher daily protein intakes than the general population. The current recommendation for general endurance training sits at 1.2-1.4g/kg per day. However, this is simply a generalised figure that will cover most endurance athlete’s needs. As with strength training, protein ingestion should be matched to training output. If an athlete is beginning a new phase of training that requires an increase in volume or intensity, they are advised to consume a higher protein intake. Once they settle into the new routine of the training programme, this figure can be reduced. The Australian Institute of Sport suggests the following recommendations for protein intake based on the level of training an athlete is completing:

• Recreational athletes or athletes in a general maintenance phase– 1g/kg/day
• Moderate-intensity athletes completing 4-5 sessions of up to 60 minutes duration – 1.2g/kg/week
• Starting a new training block/heavy training – 1.4-1.6g/kg
• Elite endurance athletes able to maintain high intensities for prolonged periods – 1.6g/kg/week
• Extreme loads, multiple training sessions in a day or very long duration training – 2g/kg/day

Note: Female athletes have less muscle mass on average, so can likely reduce these recommended levels by 15%.

Protein: Pre-exercise and during exercise

There may be an improvement in time to exhaustion to be gained from including a little protein along with carbohydrates during long-duration exercise. Stearns et al (2010) performed a systemic review and meta-analysis on the subject of combining protein with carbohydrates during exercise. Their review included 11 qualifying studies that measured performance enhancement between groups consuming a traditional carbohydrate solution during exercise and groups with varying amounts of protein added to the carbohydrate solution. All 11 studies suggested an average improvement in time to exhaustion of 9%. The amount of protein ingested during the studies ranged from 7 to 45g and protein sources included whey and BCAAs.

More research is still needed in this space as it is not yet clear whether protein or simply the additional calories were responsible for the improvements. Unfortunately, the same approaches have not been found to improve actual race performance. This means ingestion of protein may allow longer exercise durations but will not necessarily result in faster times over a given distance. This was the conclusion of a review of the research by van Loon (2014) who concluded that protein ingestion with carbohydrate during exercise did not further improve exercise performance when compared with the ingestion of ample amounts of carbohydrate only and was backed up by the most recent study by Harrington (2023) who found 8g of BCAAs improved time to fatigue but not performance in a 20km road trial in elite cyclists.

There is compelling evidence to suggest that adding protein to a carbohydrate solution before or during endurance exercise may be more beneficial for reducing muscle damage (potentially by up to 30%) which could be useful for those completing daily hard endurance workouts (Saunders et al, 2004, Kim et al, 2013).

As yet there is no concrete amount of BCAA’s that are suggested during exercise, but most research studies used an approximate amount of 70-80mg/kg of body weight per hour in trials

In summary, adding a little protein into carbohydrate drinks during prolonged endurance exercise will likely not improve performance, but may reduce muscle damage during exercise and allow a faster recovery for subsequent exercise bouts. None of the studies discussed found any issues with gastrointestinal discomfort when consuming a carbohydrate/protein solution. The relevance of this information is for athletes completing over 90 minutes of continuous exercise at levels of intensity that will cause significant muscle damage.

Protein: Post-exercise

Post-exercise consumption of protein is the same for all other training. The consumption of 15-30g of high-quality protein is recommended within 2 hours of completing exercise, with further intakes of 20-25g every 3-5 hours across waking hours.

Additional considerations for ultra-endurance nutrition

Ultra-endurance athletes have a few more considerations related to nutritional intake. Firstly, in an ultra-endurance race (typically at least 6 hours duration) an athlete may expend up to or over 7000 calories.

Current research indicates that ultra-endurance athletes do not consume enough energy during a race, so always end in a state of energy deficit. Routinely, these deficits can amount to 50% of total energy utilisation (Nikoladis et al, 2018) which will have severe impacts on performance. The type of endurance exercise can also impact an athlete’s ability to refuel during exercise, for example, cycling and running races are easier to access food and drink during than a swimming race.

Up to 96% of ultra-endurance athletes report a high incidence of mild and severe gastrointestinal discomfort during events that is most likely linked to a reduced ability to meet energy requirements through food and fluid intake (Costa et al, 2018) along with a reduction in blood flow to the gut during exercise (Schiffer, 2018). This is another factor that needs to be considered when planning event nutrition for these types of athletes.

Carbohydrate

As you would expect, carbohydrates are the main source of energy required for ultra-endurance events. Ultra-endurance athletes should aim to super-compensate glycogen stores via carbohydrate-loading strategies (as discussed earlier). They should then aim to consume 90g (and possibly up to 120g) of mixed carbohydrate sources an hour after the first hour of the event. To achieve this, absorption of these sorts of carbohydrate amounts requires practice (known as “gut-training”). The maximal amount of carbohydrate absorption in the gut appears to be around 2g/minute. Therefore, theoretically, 120g/hour would be the maximum an athlete could achieve. However, research has indicated that the consumption of carbohydrates as fluid during exercise may be more limited and is dependent on a number of factors including body mass, volume of fluid, fluid osmolarity, nutrient content, and ambient temperature (Leiper, 2015).

Attempting to consume carbohydrate levels at rates above individual absorption rates during prolonged strenuous exercise will lead to carbohydrates being left in the gut and associated gastrointestinal discomfort. This is why athletes must “gut-train” to practice ingesting increasing amounts of carbohydrates in training to find their upper limit. Schiffer (2018) suggests a good aim for ultra-endurance athletes is to build up to 1g/kg/hour of carbohydrate for male athletes and 0.8g/kg/hour for female athletes.

What about solid food intake? Most of the literature agrees that events of up to four hours can be performed with the ingestion of liquid carbohydrate sources. This is recommended because liquid sources (of the right consistency) have faster gastric emptying rates than solid foods and therefore should minimise gut discomfort (Schiffer, 2018).

However, if exercising for over four hours it is recommended that athletes practice taking in real (solid) food alongside liquids. Over longer periods of exercise, most athletes begin to have gastrointestinal upsets including nausea due to high intakes of sugar.

Sports Dieticians Australia suggest that every athlete is different in regard to what they are comfortable eating during exercise, but suggests that solid food choices should adhere to the following set of guidelines:

• Foods should be rich in carbohydrates (to top up glycogen stores).
• Foods should be low in fibre (to reduce GI upset).
• Foods should be easy to digest – High GI carbohydrates. Avoid foods overly high in fat as these are slow to digest.
• Foods should be familiar – Athletes should practice food options in training and less important events (don’t try anything new on event day!)

There’s no one “best” option for what to eat during exercise and it will depend on what your individual preferences and requirements are but here are a few suggestions from Sports Dieticians Australia:

• Simple sweet sandwiches (e.g. jam, honey)
• Simple savoury sandwiches (e.g. peanut butter or vegemite)
• Bananas
• Muesli bars
• Fruit buns
• Carbohydrate gels
• Sports energy bars.

Performing on a low-carbohydrate diet

Increasing numbers of ultra-endurance athletes are purposely trying low-carbohydrate ketogenic diet approaches in the belief that they will maximise fat oxidation, prevent glycogen depletion and improve endurance. At this point in time, there is no conclusive evidence to support this. Ketogenic approaches have been shown to consistently double peak fat oxidation rates at exercise intensities of 60-80% VO2 Max, although high fat oxidation rates during ultra distances are apparent regardless of the athlete’s macronutrient intake (Costa et al, 2018). Although the ketogenic approach for ultra-endurance is intriguing, evidence simply does not support improvements in performance. While studies consistently show higher fat oxidation rates with this approach, performance outcomes are typically lower and often attributed to a reduction in exercise economy due to the increased oxygen cost of exercise (Costa et al, 2018).

Protein

In ultra-endurance athletes, protein may provide up to 19% of energy intake during an event which may further promote the idea of consuming amino acids during an event. While this may not necessarily lead to performance improvement, it may prevent the excessive breakdown of lean tissue to fuel during these long-duration events (Nikoladis et al, 2018). With the high training volumes of these athletes, it is suggested that their daily consumption of protein is towards the higher end of recommendations (i.e. 2g/kg/day) when training volumes are high. Costa et al (2018) report that Tour de France cyclists and elite Kenyan ultra-distance runners self-select 2-2.5g/kg/day of protein.

Fat

Given that ultra-endurance athletes will likely convert a larger amount of energy from fat stores during a race, it is suggested that their general diet includes a higher-than-average consumption of dietary fat. This is also recognising that ultra-endurance athletes typically have very low body fat percentages. The suggestion of course is to try and consume the majority of these fats from unsaturated sources to avoid negative effects on the cardiovascular system. There is also a suggestion that consuming higher than usual fat amounts in the days leading up to an event (and even in the pre-event meal) induces an augmentation of intramyocellular lipids in ultra-endurance athletes, which may enhance performance. This, however, requires further research before becoming a mainstream recommendation. The consumption of fat during ultra-endurance races is also something many ultra-endurance athletes engage in; however, field-controlled studies have not shown a correlation between fat intake during a race and performance gains (Nikoladis et al, 2018).

Nutrition strategies for intermittent sports

Sports are typically intermittent in nature. Most involve short periods of intense effort, broken up by either periods of rest, or lower-intensity aerobic movement. The fuelling requirements for specific sports are dependent on the volume and intensity of movement and may be influenced by positional demands.

The key difference between sports athletes and resistance or endurance athletes is the varied nature of the training that they do. Elite sporting athletes will often perform resistance training, cardiovascular-orientated conditioning sessions and skill/tactical sessions all within the same training week. These athletes will also often complete multiple sessions in a day. This means that nutritional approaches will need to vary to reflect the energy expenditure associated with each training mode and will also need to be manipulated for given training phases where the volume and intensity of training are periodised.

All sporting athletes will benefit from beginning training sessions and games with full glycogen stores (although carbohydrate loading is not necessary). They can achieve this by following general daily carbohydrate intake guidelines and ensuring 100-200g of carbohydrates in the 4 hours prior to exercise.

Nutritional intakes should then follow the guidelines for the different training modes above (i.e. resistance training guidelines for resistance sessions, endurance guidelines for cardio sessions).

Sports games or training that have durations of less than 90 minutes typically don’t require re-fuelling during exercise, but for sessions that do extend beyond that time frame, general guidelines for carbohydrate ingestion at a rate of 30-60g per hour after the first hour should be followed.

General post-training nutrition guidelines of 1-1.2g/kg of carbohydrates and 20-30g of high-quality protein will suffice for most sporting athletes.

Multi-event: Tournament nutrition

One area of consideration that can become important for sporting athletes is nutritional approaches for tournament environments, particularly those that require daily competitive matches or even multiple games a day. The key to implementing a successful nutrition strategy during tournaments is preparation. Having the right foods available to eat at the right time is key to ensuring optimal recovery and better subsequent performance.

Consecutive daily competitive fixtures

Tournaments that require competitive fixtures for multiple consecutive days are common in both court and field-based sports (e.g. basketball, volleyball, tennis etc). The first point of focus is ensuring that athletes begin the first fixture with full glycogen stores. This is in recognition that as the tournament progresses, athletes will be unlikely to achieve full glycogen stores (i.e. it can take up to 36 hours to fully replenish glycogen following an intense bout of exercise).

The next area of focus is ensuring that hydration and carbohydrate supplementation are optimal in competitive events that extend beyond an hour. Supplemental carbohydrate ingestion will ensure muscle glycogen is not completely exhausted. Post-training carbohydrate, protein, and fluid intake should be an immediate focus after a match (1-1.2g/kg of easily absorbable carbohydrates and 20-30g of protein). This will likely involve taking these post-event snacks to the event. Regular intake of carbohydrates and protein should be taken every 3-5 hours during waking hours with particular focus given to carbohydrates in the final evening meal if the next competitive event occurs the next morning. The importance of post-event nutrition practices cannot be overestimated, and athletes should be encouraged to eat following these recommendations regardless of whether they feel like it at the time as this will be a key factor in performance towards the back end of the tournament.

Multiple daily fixtures

Some tournaments require teams to play multiple fixtures in one day. This presents athletes with difficulty in following standard pre and post exercise nutrition guidelines due to fast turnarounds and a lack of time for complete recovery practices. In these tournament situations, teams are often required to take all snacks and meals to the venue as they are often present at the venue for the entire day. This requires a good deal of additional preparation. Failure to do this often results in athletes making their own nutritional choices by buying whatever food is available or nearby. Athletes who make food choices at shops or convenience stores need to know how to make the best choices. Most convenience options are high-fat, high-calorie foods that are not designed to maximise performance. It is always wiser for athletes to prepare and bring their meals and snacks to events than to rely on bought food (or even provided food) at tournaments.

Initial pre-exercise nutrition recommendations should be followed for the initial fixture of the day, with appropriate approaches used during the match if necessary. Post-exercise nutritional intakes will be fully dependent on the amount of time athletes have between each fixture. Post-exercise recommendations for different timeline scenarios are detailed below.

One hour or less between events

• Stick with liquid carbohydrate and protein sources. This may include sports drinks, or milk-based products like chocolate milk or Up and GO which also contain important electrolytes.
• Small amounts of easily absorbed solid foods may also be tolerated such as bananas, lollies or muesli bars.

Whatever is consumed must be primarily carbohydrates and water to aid digestion and absorption and limit gastrointestinal discomfort during the next event. Because the amounts athletes can tolerate will be relatively small, re-fuelling with carbohydrates and electrolytes should begin earlier during the next event in recognition that there has not been sufficient time to replenish glycogen stores. Fuelling for Performance, (n.d.) suggests beginning this re-fuelling process after around 30 minutes of activity.

Two to three hours between events

• Foods containing carbohydrates and some protein can be eaten, as there is enough time to digest them before competition.
• Easy carbohydrate and protein-containing combinations include cereal with low-fat milk, muesli bars, beef jerky, fruit, pretzels, chocolate milk, or bread sources such as English muffins or sandwiches including a small amount of protein or peanut butter are appropriate. Avoid high-fat foods.
• The aim should be to consume approximately 0.5-1g/kg of carbohydrates and around 15g of protein during this period (depending on whether 2 or 3 hours are available). The focus should be on getting this food in as quickly as possible after the first event to ensure enough time to digest and absorb it.
• For those who struggle with solid food, supplementing with fluids like sports drinks and milk-based fluids can be a good option. Avoid drinks that contain caffeine, carbonation, and other stimulants.

Four or more hours between events

Athletes can now start to employ standard post-exercise nutritional strategies and may benefit from a more meal approach (than a snack) when this time frame is available. Essentially intakes should reflect standard pre-exercise recommendations by choosing a meal higher in carbohydrates, moderate in protein and low in fat such as:

• Sandwiches with a lean protein source Greek yogurt with fruit.
• White Pasta or rice dishes with lean protein and vegetables.

These can be followed up at the 2-hour mark with other carbohydrate snacks like:

• Fruit.
• Cereal and yoghurt.
• Muesli bars.
• Liquid meal replacements – e.g. Up and Go.

The New South Wales Institute of Sport provides a handy infographic for its athletes to reference during tournaments.

Right, time to apply what you have learned. Head to your assessment for an assessment guide video and instructions on submitting your assessments. This assessment will require you to apply the knowledge you have learned and practised by completing a case study relating to Performance Nutrition strategies.

The assessment guide video explains your assessment task in detail, which requires you to use the information you have learned on this topic to help a case study client.