Sep 6, 2022

Many of you start workouts in a dehydrated or under-fuelled state which can reduce your performance.  Ask yourselves, do you put the same kind of effort and attention into the food and meals you eat each day as you do your workouts? This might seem like a strange concept, but if you think about it, our encounters with food are far more frequent throughout the day than the time we spend exercising. If we didn’t have a plan for our workouts each day and had to come up with them on the spot, we likely wouldn’t accomplish as much as we otherwise could if it were all planned out. Similarly, with nutrition, our food choices are likely to be poorer when we wait until the last minute to decide what to eat rather than plan ahead.

The intensity at which you are exercising is going to dictate whether you are utilizing mostly fat or carbs as your primary fuel. Carbohydrates are the body’s preferred and most efficient fuel source, so at higher intensities, particularly when we are anaerobic (think Z3 and above), carbs are a necessity. Fat, on the other hand, requires more oxygen and multiple steps to be converted to usable energy, making it the primary fuel for lower-intensity exercise (Z2, Z1). With this understanding, it makes sense why carbohydrates are essential for performance.


If you wish to perform at a high intensity in your training or race, it is important to supply your body with sufficient carbohydrates beforehand. Your muscles and liver can store a finite amount of carbohydrates before they’re completely depleted. Since these stores are rarely at full capacity, it’s important to fuel with carbohydrates beforehand. The timing of your food intake prior to exercise will determine the quantity of carbohydrates, as well as, the quality or type of carbohydrate (complex vs simple/Low GI vs High GI). ‘Complex/Low GI’ carbs provide more sustained energy but take longer to digest and process, while ‘simple/High GI’ carbs provide more immediate energy, digesting and absorbing rapidly into the bloodstream.

Most pre-workout meal options should include a variety of both simple/low GI and complex/high GI sources, while smaller snack options closer to workouts should consist of mostly simple/high GI sources. When it comes to amount, this is where it can be important to trial and error for yourself to determine what your body can comfortably tolerate prior to exercise. The larger the meal or snack, the more time needed for digestion. Keeping fat and fibre content low will aid in faster digestion.

*High GI foods may be easier on the stomach and more beneficial for those of you who have gastrointestinal issues.

When glycogen stores become depleted, fatigue and reduced performance start to happen.  Unless the central nervous system, particularly the brain, has enough carbs available it will also cause fatigue which can result in impaired pacing, skill concentration, and increased perception of effort. Simply put, fuelling with carbohydrates during longer bouts of exercise is essential for optimal performance. A common mistake is fuelling too late. Whether it be a race or long training session, intra-workout fuelling recommendations start in the very first hour. To space out carbohydrate doses and minimize GI upset, a good rule of thumb is to consume 15-30 grams of carbohydrate every 15-30min.

You also need to consider the duration of your workout:

Duration of CompetitionExercise IntensityFuelling RecommendationsOther notes
<45-60min<75% VO2 MaxWater is often adequateConsider additional fueling if extremely intense or important session
45-75minHigh Intensity; >75% VO2 MaxBegin to take in some carbohydrates to maximise performance.Consider rapidly absorbable carbohydrate sources
1-2hrAny intensity, but especially if >75% VO2 Max30g of carbohydrate/hrSport Drinks, gels, energy chews/blocks. Can break this up to 15g/30mins
2-3hrAnyAim for up to 60g of carbohydrate/hrPractice fueling in training to test gut tolerance & palatability.  Again break that amount up into smaller amounts every 15-30mins.
>3hrAnyExperiment with taking 60-90g up to 120g of carbohydrate/hrInclude multiple carb sources (glucose/fructose + maltodextrin) for absorption of >60g/hr (this is dependent on how well your gut responds to fructose & maltodextrin). Higher carb intake is associated with improved performance, better recovery & lower RPE during prolonged sessions & races.  Add protein up to 0.25g/kg/hr.

*These suggestions are nutrition for endurance performance, not just “getting through” a workout, but actually performing better during it.

In general, you want low fat and fibre content, and low-moderate protein content pre-workout as these can all potentially cause gastrointestinal difficulties and promote gastric emptying! 


Choose low-fat, low-fibre, moderate protein carbs that you have eaten in practice and know settle well for you when you are nervous.

Low GI Foods v High GI Foods – consuming either of these before exercise yields similar performance results but some can have issues with consuming too many low GI or high fibre foods too close to training/racing and struggle with abdominal cramping, gas or diarrhoea and subsequently decreased performance.  So, maybe leaning to more high GI or lower fibre, easier-to-digest foods before key workouts or races might be the better option. 

Adding protein to your pre-exercise carbohydrate intake increases the body’s natural glycaemic response (meaning slows down the carbohydrate absorption), compared to carbohydrates taken alone.  The amino acids arginine, leucine, and phenylalanine have been shown to stimulate the pancreas, help increase glycogen synthesis and promote glycogen sparing during exercise.  Try adding 8-10g of protein with your pretraining meal (1 egg, 4oz of Greek Yoghurt, 1-2 oz of chicken, 3 oz tofu are all options with this amount of protein) with your carbohydrates.


Between 1990’s & 2004 it was recommended that athletes should aim to ingest 30-to 60 grams of carbohydrate per hour during exercise, and this is still quoted now.  Newer science shows we can and should train our guts to take in more.  The more we can take in and absorb the longer and faster we can go.  Since fructose is absorbed by different transporters than glucose, ingestion of both carbohydrate energy sources leads to an absorption rate of 1.5g of carbs per minute during exercise (up to 90g/hr).  Once we train our guts to accept this higher carb intake, we can reap the benefits including a lower rating of perceived effort (RPE), better maintenance of cycling cadence, and reduced fatigue.

Additional research has shown that as you become dehydrated, reliance on carbohydrate stores for energy only increases, more reason to stay on top of meeting your carbohydrate needs, especially if in the heat.

Fuelling during events should not be based solely on body weight, as maximum absorption rates are gut-dependent rather than body weight-dependent.

When fuelling for long-distance triathlons (70.3, Ironman) or ultras, fuelling becomes the 4th discipline, you simply cannot swim, bike, and run for anything from 8-17 hours without carbs, fluid, and sodium to keep your body moving forward and your brain functioning enough to push you to the finish.

All of this should be tested in training, trying out different types of foods (eg. PB&J sandwiches, energy bars, gels, chews, dried fruit, rice balls, waffles, salted boiled potatoes, pretzels etc etc etc) to determine which type of carbs, flavours sit well and taste good for each of you.

*Be careful not to over fuel during races, and be aware of the symptoms, if you are burping a lot, feel bloated, or getting a stomach ache, these are the signs that your nutrition is not getting absorbed from your gut, try easing off the nutrition and drink some plane water or electrolytes to help dilute your gut so absorption can take place.  It is best to get your less sugary calories in early on and save your sugary ones for later as these will be quicker to absorb when your gut is under stress due to fatigue and dehydration.

*Symptoms of under-feeding can be feeling tired, and reduced performance, try to re-fuel with small amounts regularly and with some water to make it easier for absorption to take place in your gut.

MOUTH RINSING: this is taking some sports drink or gel into your mouth, rinse and spit it back out. This may be useful if you have a very sensitive stomach or you are experiencing GI issues.  What this does is activate receptors on the tongue and in the central nervous system that lead to increased performance but a downside that research has noted from some athletes’ studies, is higher reported RPE.  So I would stick to the use only if you are experiencing stomach issues with your normal fuelling.

Sweat rates vary a lot and they can range from 0.3 to 2.4 litres per hour depending on things like the weather, the individual, and the work intensity.  Losing 2% of body weight to sweat is ok, but losing more than that can negatively affect performance and cause functional impairment in concentration, especially in hot weather.  The common average range of sweat loss is 0.4-0.8 litres/hour.  As well as fluid itself, you lose sodium and other critical electrolytes in your sweat, and the concentration of loss again varies from person to person.  Losing too many electrolytes can lead to reduced performance and be a contributor to muscle cramps.  Hydration was discussed at length in my post last week.


After exercise, you have a window where your body will metabolize energy quickly, and you need to give it plenty of energy to rebuild and recover. You have depleted your muscle glycogen stores to some capacity, depending on the intensity and duration of your workout. In order to minimize muscle soreness and maximize recovery, replenishing these stores through carbohydrate ingestion is key.

Adequate carbohydrate intake after exercise is imperative for you to repair your body and maintain a high level of performance. Your carbohydrate portion should be 2-3 times more than your protein portion (20-40g age dependent) for your post-training and post-race meal.  As glycogen levels decrease your ability to work also declines as does the ability to exercise at the desired intensity.  Rates of tissue breakdown have also been shown to be higher without adequate intake of both carbohydrates and total energy. Restocking muscle glycogen is considered a primary goal for all athletes following training and racing.  Then also protein intake after exercise is also important when muscle-damaging exercise has occurred or when gains in muscle size and strength are desired.  It can take up to 72 hours after prolonged or exhaustive exercise for your body to restock its much-needed supply of muscle glycogen in your muscles.  Recovery nutrition studies have shown 50% faster glycogen depletion when cyclists consumed recovery carbohydrates within 30 minutes after exercise versus delaying that recovery nutrition by two hours.

All recommendations stress the fact that restoring muscle glycogen is a primary goal and triggering muscle repair and muscle protein synthesis. 

It is best to use moderate to high GI carbohydrate as it is absorbed more quickly by our bodies immediately after exercise (eg. white rice, pancakes, bagels, potatoes, yoghurt, smoothies, pasta, ripe banana). AVOID ANY TYPE OF ANTI-OXIDANT FOOD (VITAMINS A, C & E) AFTER EXERCISE AS THESE BLUNT THE ADAPTATIONS FROM THE EXERCISE (eg. berries, and other citrus fruits and some vegetables).

PROTEIN – depending on your age depends on how much you need in post recovery, 20 grams might be adequate in younger athletes to stimulate muscle protein synthesis, but as we age we will require more like 35 to 40g of total protein after exercise. Females need to start upping theirs as they start going through peri to post menopause hitting the 40g mark and for men 40g, over the age of 50.  This is due to the inability to synthesize muscle protein after exercise as we age.  But taking in carbs and protein within 30 minutes after exercise helps optimize recovery and adaptations needed before the next training session.  This after-exercise recovery is even more important for women as our bodies go catabolic after exercise (which means we start eating our own muscle) and we need to get out of this stressed state as soon as possible so we can get the adaptations and muscle strength from the exercise we have just done.

The best source of protein optimal for recovery is rapidly absorbing leucine which is found predominantly in dairy or whey protein.

If your workout isn’t intense and is less than 60 minutes, you may not need a post-workout snack, however, because this is when nutrients are least likely to be converted and stored as fat you might want to have the post-workout snack anyway, plus it gets you into good habits.

These are the recommended guidelines for post-workout carbohydrates:

1.2g of carbohydrates per kilogram of body weight as soon as possible and then every two hours for four to six hours or 0.8 grams of carbohydrate per kilogram of body weight plus 0.4 grams of protein per kilogram of body weight for maximum glycogen repletion and muscle protein synthesis.

Carbohydrate Source15g carb serving size30g carb serving size45g carb serving size
Cereal½ cup1 cup1 ½ cup
Pasta½ cup1 cup1 ½ cup
Rice1/3 cup2/3 cup1 cup
Beans/lentils1/3 cup2/3 cup1 cup
Sweet Potato½ cup1 cup1 ½ cup
English Muffin1/211 ½
Banana (large)½11 ½


You will likely have lost around 2% body weight, and your sweat and urine loss will continue at a greater rate than normal after workouts so you need to consume a greater amount of fluid to make up for this deficit.  Keep rehydration at a modest rate and think about the maple syrup and salt recipe I put in the hydration post as this will aid absorption and minimize the volume response which creates more bathroom visits and dehydration.

Post-workout hydration also helps to restore your blood plasma volume quickly.  

Avoid excess intake of alcohol in your post-workout hydration window because it will impair the rehydration process with its diuretic effects.


Eat a meal before and after workouts and during if over 60 minutes or intense. 

A final note: you don’t want to add that much fat to your post-workout meal because that can slow down the absorption of carbohydrates. Try to limit fat intake in the first hour after exercise.

I hope this was informative for you to help improve your performance during your training and racing.