You probably think the typical Olympic athlete's big nutritional concern is eating enough to make it through the day's workout(s). That's certainly true for some. Cross-country skiers, particularly women, have a difficult time consuming the 4,000 or 5,000 calories they may need to replace what they're burning off, says Susie Parker-Simmons, a sports dietitian with the United States Olympic Committee.
But then there's the poor Olympic ski jumper.
The physics of that sport dictate that he (a bid to add a women's event in Vancouver was rejected) be tall (5-11 and up) but weigh in the vicinity of 135 pounds, says Parker-Simmons. And because it's a power sport, endless hours of fat-burning running is counterproductive athletically—explosive power demands fast-twitch muscle fibers, not the slow-twitch fibers developed by endurance sports. That means caloric restriction, not extra exercise, is the primary means of keeping body weight low. Is it any wonder eating disorders are common? (Authorities actually require a minimum BMI in order to discourage self-starvation and anorexia.)
Between these two extremes—the ski jumper Jack Sprat and his wife the cross-country skier—lies an incredible diversity of nutritional needs that depend on the athlete's sport, gender, competition conditions, and other factors. The starting point for addressing them is no different from the one for civilians. "Athletes do not need a diet substantially different from that recommended in the 2005 Dietary Guidelines" or the Canadian equivalent, says a 2009 position statement on nutrition and athletic performance issued by the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine. That means a diet that meets at least the RDA for micronutrients such as vitamins and minerals; doesn't eliminate or drastically reduce intake of carbohydrates, protein, or fat; and is generally healthful, centered on plenty of fruits and veggies, whole grains, lean protein sources, and "good" fats such as olive oil.
From that baseline healthful diet, the tinkering starts. Here are some of the eating considerations faced by the athletes in Vancouver. If you're particularly active or athletic yourself, some of them may apply to you, too. A sports dietitian can offer advice.
Sport of choice. Generally, dietitians will prescribe a certain number of grams of carbs, protein, and fat per kilogram of an athlete's body weight to match the particular demands of her workout—i.e., its length, frequency, and intensity. Nanna Meyer, the nutritionist for United States Speedskating and an assistant professor of health sciences at the University of Colorado–Colorado Springs, says an intense training day for a skater demands about 7 to 10 grams of carbohydrate per kilogram of body weight, at least 1.5 g/kg of protein, and about 1g/kg of fat. (Less intense exercise means fewer carbs—more like 5 to 7 g/kg.) For average folks, macronutrient recommendations are usually expressed in percentage of daily calories. The acceptable range is 10 to 35 percent protein, 45 to 65 percent carbohydrates, and 20 to 35 percent fat. For a 2,000-calorie diet, that would mean between 50 and 175 grams protein, 225 to 325 grams carbohydrate, and 44 to 78 grams fat per day. To keep calories constant, obviously, the more you have of one nutrient, the less you'll have of another.
While athletes do follow a balanced diet, Meyer tends to recommend a little more protein for sprinters, especially after an exercise session, to help build the muscle that characterizes their physique. Longer-distance competitors often need more carbohydrates for recovery, she says.
Weight and body composition goals. Athletes whose sports require a relatively small energy expenditure—like ski jumpers—or who are above their ideal competition weight need to lose pounds without chipping away at the muscle that makes them successful. For a skater attempting to drop a few pounds, Meyer says she will continue to match the carbs to training needs, since that's the main fuel for performance, but will increase the protein to 2g/kg and reduce fat consumption. She says that combination will protect against losing lean muscle mass as weight declines.