Fuelling For Athletic Performance

Fuelling For Athletic Performance


Whether you are a competitive or recreational athlete, everyone should know the basics when it comes to fuelling your body before, during, and after a workout. Although every person’s nutrient needs are individualized to their age, gender, genetics, body composition, health status, and activity level, this blog can provide a general recommendation for eating to achieve optimal performance. 


Carbs, carbs, carbs!

Carbohydrates are fundamental to physical activity because they are the main source of fuel for our body’s “machinery.” When we consume carbohydrate, our bodies store it in two ways, providing us with a short-term and long-term energy supply. Immediately following a meal, chains of carbohydrate are broken down into glucose, absorbed into the bloodstream, and converted to ATP, the body’s main energy currency. This creates a glucose reserve that is readily available during times of increased energy needs. However, as ATP begins to accumulate, the body is programmed to re-assemble dietary glucose into long chains of carbohydrate in the muscles and liver (called glycogen). This provides storage centres for energy that can be drawn from when blood glucose runs low, especially during endurance activity.
In order to maintain adequate blood glucose levels and a constant store of glycogen, athletes need to increase their energy intake according to the duration, frequency and intensity of their workout. In particular, athletes should consume additional carbohydrate and protein. So…bring on the chips, crisps and biscuits? Not quite. It is a common misperception that athletes can eat “whatever they please,” with no health repercussions. Nutrient-dense foods are quite important for repair and recovery post-workout, therefore, extra carbohydrate should come from fruits, vegetables, and whole grains and extra protein should come from low fat dairy products, pulses, leans meats, fish and poultry. Not only will this optimize your performance, but it will also allow you to maintain a healthy body weight and help reduce the risk of injury.
On the other hand, insufficient energy intake, especially from a lack of carbohydrates, is likely to have detrimental effects on athletic performance. When athletes restrict calories over a period of time it forces them to obtain energy through protein oxidation 2. This situation is problematic for the body, which prefers to use carbohydrates as a source of glucose. In response, there is usually a loss of lean tissue followed by a “loss of strength and endurance, and compromised immune, endocrine and musculoskeletal function 2.” 

Lean, mean protein machines

Protein has countless functions in the human body and is especially important for the maintenance and recovery of muscles. For the average man or woman, the daily recommended amount of protein is 0.8 grams per kilogram of body weight – approximately 55.5 g and 45 g, respectively 1. To put this into perspective, an average chicken breast is roughly equal to 30 g. Yet, for endurance athletes (runners, cyclists, swimmers), this recommendation increases to 1.2 – 1.4 g/kg/day and for strength athletes (weightlifting) it increases to 1.2 – 1.7 g/kg/day 2. This may seem daunting, but in fact, most people in the US and UK consume more than the recommended amount of protein on a daily basis 1. Protein utilisation by the muscles plateaus at intakes of around 30 g, so it is better to eat small regular amounts through the day rather than big amounts in one or two sittings 3.  It is best to derive protein from foods like meat, fish, eggs, dairy products, beans, pulses, nuts and seeds. However, protein supplements may be useful in some instances, for example for those that find it difficult to eat protein foods at breakfast, for those with very high daily requirements (e.g. a 120 kg rugby player), or those who may not be able to eat straight after training. However, protein supplements are largely unregulated so the type and amount should ideally be recommended by a nutrition expert. 


Choose a balance of foods that are high in carbohydrates, moderate in protein, and low in fibre and fat.  The timing of the meal is up to your discretion, but should be consumed in a strategic way that will leave you feeling comfortably full before your workout. Here are 4 quick and easy meal ideas that will extend satiety and prevent gastrointestinal discomfort:
  • Banana or apple with peanut butter
  • Greek yogurt with raw oats and berries 
  • 100% fruit juice, an egg, and a piece of wholemeal toast
  • Hot or cold cereal with skimmed milk, nuts, and fresh/dried fruit 
To ensure adequate energy, consume these meals 1 to 3 hours before the start of exercise. For meals eaten 3 to 4 hours before the start of exercise, athletes should strive for approximately 1-4 g/kg body weight of carbohydrate 4. This is a wide range, and requires some experimentation to find out what works best for you and your exercise programme.  As a reference, there are 15 g of carbohydrate in a standard-sized piece of bread. Hydration is also extremely important and can be achieved through the ingestion of fluids and water-rich foods such as fruit, vegetables and salads.

During exercise

Fluids are essential, so stay hydrated by drinking water. If exercise should exceed 1 hour, sports drinks can be useful as they provide electrolytes and a small amount of carbohydrate to maintain adequate blood glucose levels. However, for endurance athletes performing long sessions sports drinks may be better avoided as the added glucose limits fat burning – the very adaptation you are trying to promote in a long session!


Here you have two main goals. First, replenish glycogen stores and second promote muscle repair. Unless you are training again within 8-hours there is no particular need for a specific recovery supplement and the focus should be on eating the right types of food. Carbohydrates and protein should therefore be the main focus of the recovery meal. Strive to eat within 30 minutes post-workout and continue to replace fluids and electrolytes. At this point, it is acceptable to start incorporating more complex carbohydrates and healthy fats. Here are four energy-dense snacks:
  • Wholemeal wrap with chicken and vegetables
  • Smoothie made from skimmed milk and fruit 
  • Cheese on wholemeal crackers
  • Low fat chocolate milk



References & Works Cited
National Health Service (NHS) (2011). Supplements: Who Needs Them? NHS Choices. 1-34. Retrieved from http://www.nhs.uk/news/2011/05May/Documents/BtH_supplements.pdf
2 Academy of Nutrition and Dietetics (AND) (2009). Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the American Dietetic Association, 109 (3), 509-527. Retrieved from http://www.eatright.org/About/Content.aspx?id=8365
3 Areta JL, Burke LM, Ross ML, Camera DM, West DW, Broad EM, Jeacocke NA, Moore DR, Stellingwerff T, Phillips SM, Hawley JA,  Coffey, VG (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. J Physiol; 591(Pt 9):2319-2331.
4 Burke LM, Kiens B, Ivy JL (2004). Carbohydrates and fat for training and recovery. J Sports Sci, 22(1):15-30.

 Tags: nutrition, training, health, vitamins, food

The Institute for Optimum Nutrition is an independent educational charity.
Registered company number 2724405, registered charity number 1013084