第155页 | The Big Book of Endurance Training and Racing | 阅读 ‧ 电子书库

Fat Burning

If you want to achieve optimal endurance, then you need to burn more fat. It’s that simple. Your body has plenty of fat stores, where most of the fat you eat is first deposited. This stored fat, even the small amounts in super-lean athletes, represents a tremendous reserve of potential energy. For example, an endurance runner who is six feet tall and weighs 150 pounds has enough potential energy stores from his fat stores to power a run for over 100 hours. Trying to obtain more energy from sugar won’t come close to that feat.

During rest, fat may contribute significant amounts of energy, up to 60 to 80 percent, or more. The same is true during light to moderate workouts, where fat may provide well over half of the necessary energy; likewise during longer training periods and competitions. In well-trained athletes, up to 80 percent or more of their energy needs can come from fat during training. From a standpoint of athletic performance, eating enough fat helps a well-trained aerobic engine burn more fat for energy. And an increased consumption of dietary fat spares stored glycogen during exercise, an important function for endurance and competition.

To maintain efficient fat burning, we also must burn some sugar in the form of glucose. Both fat and sugar are almost always being used for energy at all times. Right now, you may be getting half of your energy from fat and half from sugar. When you improve your aerobic system and fat-burning capabilities, you may be able to obtain 70 percent of your energy from fat and 30 percent from sugar. But many people can only get 10 percent of their energy from fat, forcing a full 90 percent to come from sugar. That’s a very inefficient way to get energy and it could lead to fatigue, increased body-fat stores, and other problems. In fact, it became evident to me decades ago that those who burn more fat for energy are healthier, more fit, recover better, and have less illness and injury.