train for just an hour a day , whereas an endurance athlete will train for three hours or more . To sustain that level of training , sprinters need to eat around 5g of carbs per kg of body weight every day , whereas endurance athletes need at least 7g per kg . For Jamaican sprint sensation Usain Bolt , that means consuming some 450g of carbs a day , whereas , while Ethiopian distance demon Haile Gebrselassie would need at least 380g . Despite doing less training , Bolt would have to eat more carbs simply because he weighs more . So what 's the fuel of choice for these elite athletes ? `` In general , endurance athletes are better about getting a variety of carbs , just because they have to eat so many they get bored . They 're good at mixing up pasta , rice and potatoes , '' says Stear . Because `` strength-and-speed '' athletes do less training than endurance athletes , they have to watch their weight . Stear says sprinters often favor low glycemic-index carbs to help them keep their weight in check . What is the glycemic index ? Carb
-LRB- CNN -RRB- -- Just what is it that separates a champion athlete from the also-rans ? Natural talent , hard work and determination are all essential , but athletes and coaches are becoming increasingly aware of the crucial role diet plays in sporting success . Olympic athletes are fueled by high-carb diets . Dr Samantha Stear is national lead for performance nutrition at the English Institute of Sport -LRB- EIS -RRB- and helped make the Beijing Olympics Britain 's most successful games for a century . `` A good diet is n't going to turn a mediocre athlete into a champion , but a champion eating a bad diet may just miss out , '' she told CNN . Training is the key to improving athletic performance , and the right diet is the key to sustaining a punishing training regime . Your body uses glycogen stored in the muscles to provide the energy needed for exercise , and the body makes that glycogen by breaking down the carbohydrates you eat . So carbohydrates are the vital fuel needed for training , and the more training an athlete does , the more fuel they need . Sprinters will often