Diets of elite athletes: has the discipline of sports nutrition made an impact?

Although numerous descriptions exist of special diets and particular foods used by Greek athletes as early as 580 B.C., survey data on diets of Olympians of the modern era are virtually nonexistent. A survey in Helsinki in 1952 reported the diets of Olympic athletes to be high energy, high fat, and high protein. The 1952 Olympians reportedly consumed an average daily energy intake of 18,841 kJ, with 40% of energy coming from carbohydrate, 20% from protein, and 40% from fat. More recent data on elite level athletes reveal wide variation in dietary intake. For example, energy intakes of athletes from four countries ranged from 7699 to 24,845 kJ. Group percentages of energy from carbohydrate, protein, and fat ranged from 33 to 57%, 12 to 26%, and 29 to 49%, respectively. Comparing dietary intake data of athletes on an absolute basis, however, is primarily a comparison of body size. When the protein and carbohydrate intakes of elite athletes are calculated as grams per kilogram body weight, the range for protein is 1.0-4.3 g/kg body wt for protein and 3.5-6.9 g/kg body wt for carbohydrate. Interestingly, variations in carbohydrate intake diminished while protein intake varied by country. Although some data on diets of Olympians exist, the most remarkable finding when reviewing the literature is the paucity of data. The discipline of sports nutrition has arguably had a positive effect on sports performance. However, many unanswered questions remain and great strides remain to be made.