Diet crucial to athletes
Optimizing nutrition for athletes is intense work. Cross-country skiers have the highest energy expenditure of any sport in the world and must be regularly tested, said Susie Parker- Simmons, a sports dietitian for the U.S. Olympic Committee. An average woman needs 4,000 calories or more per day to train and compete; a typical man needs 7,000. Ski jumpers, meanwhile, sometimes have to drop 10 kg below their natural weight, while keeping up muscle mass and energy.