Different endurance, different nutritional needs...

For both non-endurance athletes such as footballers and for endurance athletes, such as a long-distance runners, carbohydrates makeup an important part of your diet, but for different reasons.

Needs of non-endurance athletes

For non-endurance athletes, such as footballers, tennis and rugby players, and weightlifters, the bulk of their calorie intake (55-60 per cent) should come from carbohydrates - mainly starches and a small proportion from sugars. No more than 30 per cent of their calories should come from fat and the remainder (10-15 per cent) from protein. As with any diet, it should be well-balanced and provide all the necessary nutrients.

Glucose and glycogen for non-endurance athletes

When starches or sugars are eaten, the body changes them to glucose, which is the only form of carbohydrate used directly by muscles for energy. Glucose is also stored in the liver and muscles as glycogen. During exercise, glycogen is broken down to provide energy. There is usually enough glycogen in the muscles for 90-120 minutes of exercise. Most exercise and sport do not use up your glycogen stores so eating carbohydrates during the activity is not necessary.

Here are a few tips for non-endurance athletes about what to eat and drink before, during, and after exercise:

• Before: Have some high-carbohydrate foods like a banana, bagel, or fruit juice. These foods are broken down quickly and provide glucose. Researchers have found that eating something between one and four hours before exercise keeps glucose available for working muscles. It is also critical to drink plenty of water beforehand to keep muscles hydrated.

• During: Perspiration and exertion deplete the body of the fluids necessary for optimum performance and lead to dehydration. Drink plenty of water - at least 120ml (4floz) every 20 minutes of exercise. Replace carbohydrates with a sports drink if the exercise lasts over 90 minutes.

• After: If the exercise was strenuous and lasted a long time, glycogen stores may need refuelling. Foods and drinks high in carbohydrates right after exercise will replenish glycogen stores.

Needs of endurance athletes

Carbohydrates are the most important nutrient for endurance sports, such as marathons and long-distance cycling, swimming, or cross-country skiing.

• Carbohydrate loading: Before an event, some athletes practise “carbohydrate loading”, an approach that maximizes stores of muscle glycogen, which is the first fuel to be used during intense exercise. To achieve this, you limit your intake of carbohydrates for a few weeks before eating a lot of them in the days before the event. The initial reduction in carbohydrates makes the body extremely sensitive to them when they enter the body, allowing glycogen stores to be replenished. See here for a healthy carbohydrate-rich meal to eat the day before an event.

• Day of the event: It is best to eat a light breakfast, such as cereal or toast and fruit juice. After breakfast, drink water in small amounts at regular intervals to ensure you start the race fully hydrated. Since the body's carbohydrate stores become depleted during the exertion of an endurance event, replace them whenever possible. Sports drinks help maintain diminishing stores of energy, water, and nutrients, especially salts lost in sweat, throughout the event. Up to 4-5 litres (7-9 pints) of sweat may be lost when running a marathon. After the event, the body's water and energy levels need to be restored as soon as possible.

• What to avoid: Endurance athletes should avoid coffee, tea, and alcohol because they might lead to dehydration. Some athletes, however, do take caffeine just prior to a race to enhance performance.

Lisa Hark, PhD RD & Dr Darwin Deen

Nutrition for Life Copyright © 2005 Dorling Kindersley Text copyright © 2005 Lisa Hark and Darwin Deen

Posted 14.02.2011

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