Nutrition before, during and after workouts | EP#100
A research-based review of nutrition before, during and after endurance exercise and competition, looking especially at triathlon nutrition.
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In this Episode you'll learn about:
- Hydration and carbohydrate before exercise
- Hydration and carbohydrate during exercise
- Hydration, carbohydrate and protein after exercise
- Example meals, snacks and supplements
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Background & evidence base
- Follow on episode from two previous podcast episodes earlier this year:
- The research base for all three podcasts is the Joint Position Statement from 2016 called Nutrition and Athletic Performance published in Medicine and Science in Sports and Exercise.
- Most of us know that if you haven't eaten properly leading up to a workout, or during a workout, it can lead to a reduction in your performance, including your power, endurance, and concentration skills.
- The most common reasons for this are glycogen depletion or hypoglycemia, dehydration or electrolyte imbalances.
- Another reason for performance reduction is gastrointestinal discomfort, which may be caused by eating or drinking the wrong things.
- Therefore, it's important to be mindful of how we eat, hydrate and what we supplement with both before and during and after a workout.
Fuelling before a workout - hydration
- Many athletes start workouts in a dehydrated/hypo-hydrated state which can reduce performance.
- If you are dehydrated, your blood plasma volume decreases and that leads to increased cardiovascular strain, increased glycogen utilisation, increased body temperature, as well as altered central nervous system functions.
- You need to hydrate well in the 2-4 hours before exercise.
- Check your urine to test hydration levels, it should be a pale yellow colour.
- It's also important to leave enough time to get rid of excess fluid before you begin the workout.
- Also, include some sodium in your pre-workout fluid or food as this will help with fluid retention.
- People lose a lot of sodium through their sweat - check out Precision Hydration's free online sweat test to get your ballpark number.
Fuelling before a workout - carbohydrate
- It is mostly carbohydrates that must be considered before a workout as a lack of carbs is one of the main causes of fatigue and reduced performance.
- Unless the central nervous system, particularly the brain, has enough carbs available it will also fatigue which can result in impaired pacing, technique, concentration and increased perception of effort.
- Related listening: Brain training and psychobiology of endurance performance with Professor Samuele Marcora | EP#17
- Carbohydrates does not equal grains! You don't need to just fuel on pasta, you can get by on fruits and vegetables but may need to eat more of them.
- You also need to consider the duration of your workout:
- For a low intensity workout less than 60 minutes you can eat what you'd eat on a normal rest day.
- For longer workouts, or short workouts with significant amounts of intensity (e.g. interval workouts), you will need to consume 1-4g of carbs/kg of bodyweight in the 1-4 hours before the workout.
- E.g. If you weigh 70kg and you have a medium duration workout with moderate intensity, you could have 2.5g/kg bodyweight of carbohydrates, which would be 175g of carbs. To fulfill this you may need an actual meal and possibly also a snack containing carbs before the workout.
- 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.
- According to the position statement "neither the glycaemic load nor glycaemic index of carbohydrate rich meals affect the metabolic nor performance outcomes of training once carbohydrate and energy content of the diet have been taken into account".
- So the pre-workout carbs don't need to be high on the glycaemic index, you can get the fuel from clean carbs such as beans, fruit and sweet potato (just to give a few examples).
- However, high glycaemic index foods may be easier on the stomach and thus beneficial for people who have gastrointestinal issues.
- The time you consume your pre-exercise meal does matter.
- If you're eating <1 hour before the workout, go for something like a banana that's got a high glycaemic index and will be easy to absorb.
- If you're eating 2-3 hours before, then something like beans, or any lower glycaemic index source of carbs might be just as good.
- Real life examples:
- Pre morning workouts: Fruit, oatmeal with yoghurt and berries, and coffee.
- Pre afternoon workouts: Salad with lots of fruit and vegetables, plus some protein source like tuna.
- Snack: 1-2 bananas or slice of bread or dates.
- 15 minutes before workout: banana slice of bread or sports drink.
Fuelling during workouts - carbohydrate
- If your workout is 75 minutes or longer, or it's a shorter but highly intense workout, you will improve your performance by taking on carbs during the exercise.
- Reducing perception of effort through the activation of the reward centres in your brain can be done through mouth rinsing without actually consuming the carbs.
- You can take either some sports drink or gel into your mouth, rinse and spit it back out.
- This may be especially useful if you have a very sensitive stomach, you are experiencing GI issues, or you are in a weight loss phase (although in general, you should forget about weight loss when you're actually doing your workouts).
- During exercise the recommendation is to have some sort of sports product - they are designed to be absorbed quickly and to bring the maximum amount of carbs in the shortest amount of time.
- They will stay in your blood stream and your muscle will take up the glycogen and use it to create ATP and move you forwards.
- Therefore, you do not need to worry about "clean" sources of carbs when you're actually doing a workout.
- Carbohydrate requirements:
- <60 minutes workout, minimal intensity: you don't need to take on carbohydrate.
- 45-75 minute workout, high intensity: consume up to 30g/hour of carbs (as an example, a gel has ~22g carbs, sports drinks ~20-30g/500ml).
- 60-160 minute workout: 30-60g/hour of carbs (e.g. bottle of sports drink and one energy gel per hour).
- 160+ minutes workout: up to 90g/hour of carbs (e.g. bottle of sports drink and 2-3 energy gels per hour).
- You won't get any extra benefit from going higher than that because you can't absorb any more than that per hour.
- According to the position statement: it hasn't been conclusively shown that dual carb source gels (e.g. glucose and fructose) are more beneficial/absorbed faster than single source (e.g. fructose alone).
- However recent article by Asker Jeukendrup, world leading nutrition researcher, disagrees with this conclusion. He stated that even if the conclusions about metabolic effects were correct, multiple studies have shown direct performance improvements when using dual source supplements.
Fuelling during workouts - hydration
- Sweat rates vary a lot - they can range anything from 0.3 to 2.4 litres per hour depending on many factors such as the weather, the individual, the workout intensity etc.
- Related listening: Hydration, sodium and cramping with Andy Blow | EP#49
- Losing 2% of body weight to sweat is okay, but losing more than that can negatively affect performance and cause functional impairment in concentration, especially in hot weather.
- There are exceptions but they seem to mostly occur in elite athletes, and even specific subgroups such as East African runners.
- The common average range for sweat loss is 0.4-0.8 litres/hour.
- You can calculate your own sweat loss by weighing yourself in the nude before and after a training session and calculating the difference in weight. Add back any fluid you took in during the exercise and divide the amount of weight lost by the time in hours that you were out to get your hourly sweat loss rate.
- Repeat this test multiple times in a range of conditions (e.g. different intensities and weather conditions) to get your average sweat loss rate across workouts.
- As well as the fluid itself, you lose sodium and other critical electrolytes in your sweat, and the concentration of loss varies from person to person.
- Average concentration ~1g/litre, but it can vary from 0.5-2.0g/litre.
- Losing too much electrolytes can lead to reduced performance and muscle cramps.
- It is helpful to establish the sodium concentration of your sweat to fuel appropriately. The amount of sodium in a sports drink may be enough if you are a low sodium concentration sweater/low sweater, but you may need to supplement with sodium if you are a heavier or saltier sweater.
- Precision hydration offers a free online sweat test which can be really helpful.
- If you are competing at the half Ironman or Ironman level you should discuss your hydration planning with your coach because it's a critical piece of the puzzle.
- Real life example: if I go for a 3.5 hour ride, I use precision hydration electrolyte based on my sweat test and I'll take 2.5 litres (0.8 litres/hour) of electrolyte supplement. I take on 60g/hour of carbs, usually 2 gels per hour and 1 bar (per ride, not hour).
Fuelling post-exercise - carbohydrate
- After exercise you have a window where your body will metabolise energy quickly, and you need to give it plenty of energy to rebuild and recover.
- It's good to time your workouts with your meals, but if you can't it's important to have a post-workout snack.
- Everything you need you can get from "normal" food so you don't necessarily need a shake.
- If you do use a shake, make sure it's specifically for endurance sports as resistance training recovery shakes have too much protein compared to carbs for endurance recovery.
- 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 a snack you'd be having anyway shortly after the workout.
- Carbohydrates are the most important part of post-exercise nutrition as they enable glycogen store restoration.
- Your body's normal rate of glycogen re-synthesis is 5%/hour so as triathletes training a lot, you need to speed up this process by consuming carbs.
- Carbohydrate guidelines:
- 1-1.2g of carbs/kg body weight per hour during the first 4-6 hours after exercise maximises the effective refuelling time.
- E.g. 70kg person: 70-84g carbs/hour for the first 4 hours = 280-332g of carbs. This would probably be a meal but research has shown the sources can vary (e.g. chocolate milk right after the workout, or clean carbs like fruits, quinoa etc. a bit later).
- 1-1.2g of carbs/kg body weight per hour during the first 4-6 hours after exercise maximises the effective refuelling time.
- There is also research on the importance of the first 30-60 minutes, so consider this and try and get some carbs in during this window - maybe even half of the required carb content.
Fuelling post-exercise - protein
- You don't necessarily need as much protein as marketing hype would have you believe, but you do need some.
- Consuming protein shortly after your workout enhances muscle protein synthesis, and consuming it together with carbs may also help glycogen re-synthesis.
- Related listening: Triathlon Nutrition: Calories, Carbs, Fats, and Proteins – Part 2 | EP#95
- Protein guidelines:
- 0.25-0.3g/kg body weight which would be 15-25g of protein for most body sizes, to be consumed up to 2 hours after the exercise (e.g. one scoop of protein is ~20g).
- Higher doses than this will probably not be absorbed.
- Science in Sport has a good carb + protein powder specifically for endurance sports. Alternatively you can mix your own combination of whey protein and maltodextrine to tailor your post-workout snack.
Fuelling post-exercise - hydration
- 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.
- For example: If your sweat rate is 2 litres/hour and you exercise for 1 hour but consume 500ml of fluid, your deficit will be 1.5 litres. So you could aim to consume 125-150% of this deficit (1.9-2.3 litres) in the post-workout phase - 2-3 hours.
- Keep rehydration at a modest rate as this minimizes the need to go to the bathroom, which forces you to get rid of the fluid.
- Also remember to refuel with sodium - either include electrolyte in your fluid (precision hydration drink) or sodium in your food post-workout (e.g. sea salt in smoothie) and this will help with fluid retention.
- Post-workout hydration helps to quickly restore your blood plasma volume.
- Avoid excess intake of alcohol in your post-workout hydration window because it will impair the rehydration process with its diuretic effects.
- Real life example: Tie in workouts so you eat a meal before and after - for my morning workouts I eat a small breakfast before and a larger one after. With other workouts I usually have an early dinner after a long workout, or a big lunch if it's a weekend ride. Smoothies can also be a useful way of refuelling.
- You don't want to add that much fat to your post-workout meal because that can slow down the absorption of carbohydrates. Try and limit fat intake in the first hour after exercise.
Check it out
- If you've enjoyed all this information on endurance nutrition, check out the new Triathlon Nutrition resource page on Scientific Triathlon for other related listening and reading!
Resources and contact
Links and resources mentioned
- Nutrition and Athletic Performance: Position statement.
- Triathlon Nutrition: Calories, Carbs, Fats, and Proteins - part 1 | EP#94.
- Triathlon Nutrition: Calories, Carbs, Fats, and Proteins - part 2 | EP#95.
- Triathlon Nutrition resource page on Scientific Triathlon.
- Asker Jeukendrup: New position statement on Nutrition and Athletic Performance.
- American College of Sports Medicine position stand. Exercise and fluid replacement.
- Dehydration and endurance performance in competitive athletes.
- Nutrition for endurance sports: marathon, triathlon, and road cycling.
- The use of carbohydrates during exercise as an ergogenic aid.
- Pre-exercise nutrition: the role of macronutrients, modified starches and supplements on metabolism and endurance performance.
- Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations.
- The Governor has a sweet tooth - Mouth sensing of nutrients to enhance sports performance.
- Short-term recovery from prolonged exercise: exploring the potential for protein ingestion to accentuate the benefits of carbohydrate supplements.
Connect with host Mikael Eriksson
Hi! I'm your host Mikael,
I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.
I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show.
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