Whether you are semi-professional or a complete novice, knowing the basics of nutrition are essential for every athlete. On a very general level, good nutrition is important for three key areas:
- Repair and recovery of muscles after exercise.
- Building immune system and fighting infection.
- Maintaining vital organs
A good diet will not turn an average athlete into a superstar, but a poor diet may prevent an athlete from achieving their potential. In general, athletes have higher nutritional requirements than those of the general population. This includes higher calorie, fluid and some vitamins and minerals.
Carbohydrates are a key macronutrient for athletes. They are the body’s preferred source of energy and athletes should consider their carbohydrates intake pre-exercise, during exercise and post-exercise.
When we eat carbohydrates, the body breaks them down to realise glucose. Glucose is a sugar molecule which provides the body with energy. After this glucose has been utilised, the body breaks down glycogen to release more glucose. Glycogen is a storage form of glucose that is stored in the muscles and liver. Post-exercise carbohydrates are important for replenishing glycogen stores and should be nutrient-dense.
Endurance athletes such as long-distance runners, swimmers, and cyclists may take gels during events. Gels are quick-release energy sources in the form of liquid pouches or sweets. Current guidelines advise to start taking your gel after one hour of running. This is when your glycogen stores are likely to be going down. Gels typically contain 25-30g carbohydrates per portion and our bodies can digest a maximum of 60g carbohydrates per hour. Therefore, aim for 2 gels per hour after your first hour of running/cycling/swimming.
The main role of protein in the diet is for growth, maintenance, and repair of muscles and tissue. In simple terms, proteins are the building blocks of their body. Protein can be used as a source of energy for athletes. However, this rarely happens as the body’s preferred source of energy is carbohydrates.
The World Health Organisation (WHO) currently recommends that the general public consume 0.8g protein per kilogram of body weight per day (e.g. 0.8g protein X 60kg person = 48g protein per day). Athletes need slightly more protein in their diets than the rest of the population in order to repair and build muscle. However, to avoid stress and strain on the kidneys, one’s protein intake should not exceed more than 2g protein per kilogram of body weight per day.
Achieving protein requirements throughout the day is achievable through diet alone. It is not necessary to consume protein shakes and/or protein bars.
- 1 slice turkey/chicken = 7g protein
- 125g pot of natural yogurt = 6g protein
- 1 small tin of tuna (100g tin) = 19g protein
- 1 egg = 7g protein
- 25g skimmed milk powder (5 heaped tsp) = 9g protein
- 330ml (1/2 pint) low fat milk = 11g protein
- 30g low-fat cheddar cheese = 10g protein
- 60g feta cheese = 10g protein
- 50g cashew nuts = 10g protein
Be cautious with protein powders and food supplements that claim to stimulate muscle growth. Protein powders are highly processed and are often heated to a point that denatures the protein, making it difficult for the body to recognize and use. The result is elevated levels of acidity and toxicity in the body which can lead to unwanted illnesses and diseases.
Fats are a source of energy for the body. However, as previously mentioned, the body will always prioritise carbohydrates as the main source of energy.
It is recommended that fat accounts for 25-30% of total energy intake. It is important to meet these dietary recommendations as fat in the diet provides essential fatty acids for normal body functions such as eye and brain development and hormone and cholesterol production.
When choosing dietary fat sources, one should always opt for unsaturated fats, as opposed to saturated fats. Good sources of unsaturated fats include avocados, nuts, seeds, olive oil and salmon.
Adequate hydration status is of utmost importance for any athlete. Dehydration can impair performance and impact performance. Urine colour is a simple indicator of hydration status – the goal should be pale yellow, not clear and not dark yellow/brown. Don’t wait until you are thirsty to drink, at this point the body is already dehydrated.
In many cases, water is sufficient for post-exercise rehydration. However, if you have exercised for over 60 minutes, if the weather is very hot and/or if you have sweated profusely, sports drinks may be necessary to replace electrolytes (potassium, sodium, and chloride) that have been lost through sweating. For a more natural option, rehydrate with a banana for potassium and a glass of milk or add a pinch of salt to a glass of water/cordial.
Vitamins and Minerals
Food is the best source of vitamins and minerals. In general, the body should be able get enough micronutrients from a healthy, balanced diet. However, athletes can be at risk of deficiencies if they are restricting energy intake and/or excluding food groups from the diet. The most common vitamins and minerals found to be of concern in athletes’ diets are calcium and vitamin D, iron, magnesium, as well as some antioxidants such as vitamin C.
Dairy products – milk, cheese, yogurt
Canned sardines and salmon with bones
Enriched plant milks
Fortified milks and spreads
Salmon, mackerel, and trout
Green leafy vegetables, e.g. spinach, kale
Fortified bread, cereal, and milk
In summary, a healthy diet for athletes should include:
- Plenty of wholemeal/wholegrain bread, pasta, and cereal, lean meat/chicken/fish, eggs, beans and lentils, nuts, dairy, unsaturated fats, fruit and vegetables.
- Limited amounts of alcohol and saturated fat, e.g. confectionary and fried foods.
- Variety – different food types and colour contain different vitamins and minerals.
- Plenty of water – sports drinks only when necessary.
- Vitamin or mineral supplements, only when clinically indicated.
Nutritional and dietary needs and preferences differ from person to person. For bespoke advice on foods for optimizing sporting performance, consultation with a qualified nutritionist/dietitian is recommended.
Amy Meegan, BSc (Hons) Human Nutrition, University College Dublin.