Is Food the Ultimate Performance Enhancer?

Track and field Olympian Marion Jones was America's darling during the 2000 Olympic games in Sydney, bringing home three gold medals and two bronzes. She ran like a lean, high-powered machine, and credited nutrition supplements—including flaxseed oil and iron—for her superstar performances. Later, she admitted to taking steroids. Since then, accusations of using performance-enhancing drugs have become frequent among elite athletes such as baseball pitcher Roger Clemens (who still denies using steroids and human growth hormone) and American cyclist Floyd Landis (who was stripped of his title as the 2006 Tour de France winner after blood tests suggested he took synthetic testosterone). As a result, most sports nutritionists won’t recommend supplements—or even multivitamins in some cases. They’re afraid that a tainted pill could cause an athlete to fail a drug test.

"The risk of product contamination can be as high as one in five or one in six," says Martin Gibala, Ph.D., associate professor in the department of kinesiology at McMaster University in Canada. Besides, "athletes need to eat real foods to enhance performance—not supplements," says Gibala. In fact, experts say, getting the right mix of carbohydrate, protein and fat can mean the difference between an Olympic gold medal in Beijing and going home empty-handed.

Carbohydrates for going the distance

Swimmer Erik Vendt took home silver medals in the 2000 and 2004 Olympics for the 400-meter individual medley and then retired, citing the stress of training. At the time, he loved junk food and would often have a midnight snack of candy or chips. Today he's back, ranked among the top five in the world and competed in Beijing. "Nutrition has helped me tremendously, mostly by elevating my training level—and that has a direct impact on how much time I drop during my races," says the 27-year-old, who now eats an all-organic diet focused on whole foods. "Before a workout, I don’t like to stuff myself with a meal; instead, I eat enough to give me the energy I need to attack the workout properly. I eat a bagel, fruit or a bowl of oatmeal."

Like many athletes, Vendt starts with carbohydrates. Since the 1920s, researchers have known that eating carbohydrates enhances performance. "We’re still recommending carbohydrates to athletes and active individuals, but the amount depends on the sports, the individuals, and their weight and health goals," says Melinda Manore, Ph.D., a professor in the Department of Nutrition and Exercise Sciences at Oregon State University. Carbohydrates break down easily and quickly raise your blood sugar, which fuels your muscles and your brain.

Trouble is, while the body can store large amounts of protein (as muscle) and fat, it has a limited capacity to store carbohydrate. "The typical athlete can store between 400 and 600 grams of carbohydrate [or 1,600 to 2,400 calories] in the muscle as glycogen," says Nanna Meyer, Ph.D., R.D., a research associate at The Orthopedic Specialty Hospital (TOSH) who has worked with Apolo Anton Ohno and other members of the U.S. Olympic Speedskating Team as well as Olympic cycling champions. Because of this, endurance athletes, such as marathon runners, long-distance cyclists and cross-country skiers, can burn through their glycogen stores after about 90 to 120 minutes of exercise. Once glycogen is depleted, the body mobilizes fat, which muscles cannot burn at the same rate as carbohydrate. The resulting fatigue—also called "bonking" or "hitting the wall"—can be so debilitating, athletes can have difficulty moving.

To prevent bonking, long-distance athletes supplement with carbohydrates during a workout—literally, they eat on the run or the ride. Many athletes go straight for specially formulated sports gels or drinks, which provide easily digested simple carbohydrates and electrolytes, such as sodium and potassium (which are lost through perspiration), minerals that help the body maintain a healthy fluid balance and keep the heart working properly. Gels generally are easier to carry than high-carb "real foods," such as bananas or raisins (which contain potassium) or pretzels (which provide sodium). However, according to some nutrition experts, these specialized products aren’t necessarily better at maximizing performance. For example, according to a small San Diego State University study (funded by the California Raisin Marketing Board), eating raisins prior to a workout was just as effective as consuming the same number of carbs in a sports gel.