Lots of us enjoy that pumped-up, supercharged feeling of breaking a good sweat in the gym, and for some, nothing beats that sense of accomplishment when we’ve finished a good exercise session. I personally love to break a good sweat, and if my daily schedule gets too busy to fit in some exercise, I start itching to go back to the gym and burn some calories!

While each one of us has our own favourite workout, drill or fitness class, all of us share one thing in common (to a certain extent): nutrition before, during and after exercise. How do we make sure we’re eating and drinking all the right stuff to maintain and improve our exercise performance? Not all foods are created equal, and while some dietary patterns boost our exercise stamina, others can sure help mess it up. That’s why maintaining good nutrition is crucial for exercise performance. Good nutrition can also help prevent injuries, aid in healing and boost endurance.

We need energy for sports, and we get that from the calories we eat. However, our caloric needs vary according to many factors such as gender, age, weight and height, metabolism, and sports-related factors such as type, duration, intensity and frequency of exercise. It can be quite a challenge for nutritionists to create optimal diet plans for professional athletes, as their energy needs can reach 10,000 calories a day! If you’re training for a competition or major event, it’s best to consult a sports nutritionist for a good diet plan. However, for recreational sportsmen and sportswomen like myself, following a healthy, balanced meal pattern is usually enough to provide the necessary energy and nutrients.

Our body uses any and all of the following as energy sources: carbohydrates, protein and fats. It’s the intensity and duration of exercise that determine which of these are used to generate energy. For high-intensity, low-duration exercise, our bodies need an almost immediate source of energy. The fastest source of getting such energy is through glucose and glycogen (the long-chain storage form of glucose). As a quick rule of thumb, high-intensity exercise burns mostly carbohydrates, low-intensity exercise primarily burns fats, and moderate-intensity exercise burns both fats and carbohydrates at varying percentages. So for those of you who are looking for weight loss, don’t go on sprints but rather aim for slow jogging or fast walking, for example. Another factor is the exercise duration. Longer duration exercise promotes more breakdown of fats to provide energy because our carbohydrate stores start running low.

Pre-Exercise Meal

Generally, a balanced meal containing complex carbohydrates, protein and some fat is recommended. You should give your stomach enough time to digest the meal and prevent indigestion or feelings of discomfort during exercise, so try to eat 3-4 hours before the workout. Good examples of complex carbohydrates include potato, corn, rice or whole-grain bread or pasta. Along with those carbs, get a moderate amount of protein from meat, poultry or seafood, or plant-based sources like beans, lentils or chickpeas. Make sure you also add some good fats in there like oils, nuts, seeds or avocado, but avoid eating a high amount of these fats or a fatty meal, because high fat content delays food emptying from the stomach, which can cause discomfort during your workout.

During Exercise

Endurance exercise lasting for more than an hour causes the body energy stores to dip low. In such cases, replacing some of the energy could improve exercise performance and maintains the blood glucose levels. Aim for 26-30g of simple sugars every 30 mins, which is equivalent to 1g/minute of glucose delivered to the body. The easiest method of getting this amount of carbohydrates is a sports drink that has 6-8% sugar content (that means between 6-8g of sugar per 100ml). Getting a drink or snack with sugar content higher than 10% may cause nausea, stomach cramps and discomfort, and sometimes even diarrhoea.

Post-Exercise Meal

Lots of people seem to think that consuming a meal too long after exercise – or not consuming any meal at all – is helpful. Sadly, this is not the case. Consuming carbohydrates too long after the exercise session has finished can decrease the rate of glycogen resynthesis, which can actually impair the next exercise performance. If you don’t feel like eating a full meal right after exercise, it’s a good idea to get some simple sugars in your system from either bananas, fruit pops, grapes, melons or other fruits. Make sure you still eat a meal around an hour after you’ve finished your training that contains cabohydrates, protein and some fats as well.

How Much Protein?

The protein needs for sportsmen and sportswomen are different according to many factors. Generally, 1.2-1.4g/kg of body weight per day for endurance exercise, while a range of 1.2-1.7g/kg of body weight per day is acceptable for strength exercise. Very high protein intakes exceeding the recommended levels is very unnecessary and does not provide any benefit. In fact, high protein intakes can actually impair carbohydrate status which has a negative effect on exercise performance, and may also cause dehydration.

Cutting out Fats?

Is not necessary. Your body still needs fat for exercise energy. More importantly, some types of fat can help reduce inflammation and heal injuries better than others. A diet high in saturated, trans, and omega-6 fatty acids worsens inflammation, so try to limit foods containing those.  On the other hand, a diet high in monounsaturated and omega-3 fats can help reduce inflammation. Good sources of monounsaturated fats and omega-3 fatty acids include olive, canola, sesame oils, avocado, sardines and salmon.

Water Needs

Hydration status is such an important factor that makes or breaks exercise performance. That’s why you should ensure you’re properly hydrated throughout the day starting with before the training session. Approximately 2-3 hours before your training starts, aim for 400-600ml of water. Then, during exercise, stay hydrated by drinking 150-350ml of water every 15-20 mins. After exercise, lots of water has been lost from your body to sweat. That means, if you weigh yourself before and after exercise, you’re likely to weigh less afterward, but that’s only because of water lost (not because you’ve burned so much fat!). The general recommendation to restore hydration is to drink 450-650ml of water for every 0.45kg of body weight loss throughout 4-6 hours after exercise.

Electrolyte Needs

Lastly, sweat contains mostly water and sodium. Hence, you also need to restore your sodium stores. If you drink a sports drink, you’re good to go because these drinks usually contain good sodium content. If you drink water, just sprinkle some salt on your post-workout meal, and that should provide adequate sodium back into your body.


Mahan, L. K., Escott-Stump, S., Raymond, J. L., & Krause, M. V. (2012). Krause’s food & the nutrition care process. St. Louis, Mo: Elsevier/Saunders.

Laura Jabri, MSc 

Laura has a masters in Clinical and Public Health Nutrition from University College London and a bachelors degree from the American University of Beirut. Her interests include nutrition education, obesity prevention, maternal and child nutrition, undernutrition in developing countries and food sustainability solutions.  Tweet her @laurajabri

Foodtalk blog posts are written by various health and care professionals to showcase a wide variety of opinions and specialisms. 

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