Old Rule: Runners don’t rely as much as non-athletes on diet for weight management.
New Rule: Runners rely more than non-athletes on diet for weight management.
Until recently, exercise scientists believed that variables such as VO2max (or aerobic capacity) and running economy were the most powerful predictors of running performance. But recent research has revealed that body composition is equally important. One study involving elite Ethiopian runners found that those with the least body fat had the fastest race times.
Each runner’s optimal racing weight falls near the bottom end of his or her healthy weight range because excess body fat is dead weight that increases the energy cost of running. A typical runner who sheds just one pound of body fat could see a one-minute improvement in his or her marathon time without any change in fitness.
The runner’s goal of reaching his or her ideal racing weight is more challenging than the average non-runner’s goal of staying within his or her healthy weight range. To reach racing weight, runners have to eat more carefully than non-runners must eat to avoid becoming overweight.
Complicating matters for runners is something called the compensation effect. The more a person exercises, the more his or her appetite increases and the more he or she eats. Simply ignoring the increased appetite is not a viable solution, but neither is an extra-large, double-cheese pizza.
Instead, runners must increase the quality of their diets. High-quality foods such as vegetables are less calorically dense than low-quality foods, satisfying the appetite with fewer calories. The six high-quality food types are vegetables, fruits, nuts and seeds, whole grains, lean meats and fish, and dairy. And the four basic categories of low-quality foods are refined grains, fatty meats, sweets and fried foods.
Take-Away Tip: When training for a marathon, fuel with high-quality foods to reach the starting line lighter. Muscles burn less glycogen at goal pace, meaning you’re less likely to hit the wall.