What we eat before a workout or training session can have significant impact on performance during your session. The wrong foods, consuming too little or not timing a meal efficiently can dramatically affect performance.
Carbohydrates (carbs) are our body’s main source of fuel for daily living and for physical activity. Carbs are stored as glycogen in our muscles and liver. Glycogen in our liver is used to regulate blood sugar levels, whereas glycogen in our muscles predominantly fuels physical activity. Having readily available carbs will allow you to exercise at a higher intensity for longer.
The majority of nutrients in a pre-workout meal should come from carbs. Some protein should be consumed, but not too much as protein takes longer to digest and doesn’t serve an immediate need for the beginning of an activity. Fat and high fibre foods should also be moderate to reduce the risk of stomach discomfort during activity.
Pre-workout meal
Depending on exercise intensity and duration, a meal 3-4hrs before exercise can be beneficial to top up your muscle glycogen (carbohydrate) stores ahead of your activity. This is especially important if your activity will be longer than 1 hour in duration and/or will be high intensity. This meal should be high in carbohydrates (1-4g carbohydrate/kg body weight) and contain moderate amounts of protein and fat to ensure full digestion ahead of your activity. This could be your breakfast or lunch meal. Example meals could be:
Rice/pasta, chicken (or other protein) and vegetables
Oats with semi-skimmed milk, fruit and nut butter or seeds
Chicken/tofu stir fry with noodles
Sandwich with choice of protein filling
Baked potato with tuna or baked beans and cheese
Pre-workout snack
To top up your liver glycogen ahead of your activity, about 30-60min before your workout starts, aim to have a smaller, easily digestible snack high in carbohydrates (0.5-1g/kg body weight), low in protein and fat. This should be around 100–300 kcal. For example, for someone with a bodyweight of 60kg, a snack with approx. 30g of carbohydrates (0.5g/kg of their bodyweight) could be:
A banana + a glass of orange juice
A slice of white toast with jam
A handful of jelly sweets
Around 4 dates
If working out first thing in the morning, some people prefer to not eat anything i.e. training fasted. If your workout will be less than 1 hour and low intensity, then training fasted is generally okay. However, if continuously training fasted for higher intensity exercise and sessions of longer duration, this can increase the risk of poor performance, strains, sprains, stress fractures and other injuries from exercise-related fatigue. (1) Furthermore, letting the body get too depleted may lead to overeating afterwards. Having a high carb snack (such as the above examples) ahead of your workout would be better.
You can trial and error your eating windows before training to see what works for you. Do not try new foods or try something you've never done before an important event/competition!
Hydration
Finally, you should ensure you’re adequately hydrated before your workout! Pre-workout fluids are essential to prevent dehydration. Aim for around 400-600ml of fluid at least 4 hours before your workout. Keep hydrated throughout the day, and if training in the morning, have water first thing and up until your session. You can use the colour of your urine as an indicator of how hydrated you are. Aim for urine that's pale and light in colour. If you're not producing urine or your urine is dark in colour before your workout, continue to drink fluids.
References:
Bean, A. The complete guide to sports nutrition. Eighth edition. Bloomsbury. 2017