
I’ve never been hungrier than I was when I trained for Ironman
Wisconsin in 2002. I trained hard for that race—up to 20 hours a week—and the
harder I trained, the hungrier I became. I like to eat, so for a while I
enjoyed the increased eating I needed to do in order to quiet my tummy. But
eventually my appetite became an outright burden. I would eat a huge dinner at
six o’clock in the evening and 90 minutes later I was hungry again. During the
last few weeks before my taper it seemed as though I was eating pretty much nonstop
between dinnertime and bedtime.
My experience is hardly unique. What’s true for me is true
generally: as the volume or intensity of exercise increases, appetite and food
intake tend to increase as well. Research has shown that chronic exercise
increases the sensitivity of the body’s hormonal appetite signaling system,
stimulates unconscious changes in food preferences, and alters the pleasure
response to food in ways that significantly boost daily calorie intake. Studies
in which overweight, sedentary men and women have been placed on exercise
programs have found that for every 10 calories a person burns through exercise,
three more food calories are consumed as a result of increased appetite.
Scientists refer to the elevation of food intake that follows
increases in exercise as the “compensation effect”. The strength of the
compensation effect varies between individuals. Some people do not eat more
even when their exercise level increases drastically, while others have been
known to gain weight while training for marathons and triathlons.
Obviously, this latter scenario is a problem. Body weight and
body composition have strong effects on endurance performance. Each athlete has
an optimal “racing weight”, which is usually at the lower end of his or her healthy
weight range. The compensation effect often prevents athletes from reaching
their racing weight and thereby hurts performance.
You can’t beat the compensation effect by ignoring your appetite
and continuing to eat as much as you did when you were training less. Resisting
strong hunger pangs day after day through weeks of hard training would require
an inhuman amount of willpower. A more effective way to thwart the compensation
effect is to focus on increasing the quality of your diet.
High-quality foods—namely, vegetables (including legumes),
fruits, nuts and seeds, lean meats and fish, whole grains, and diary—are highly
satiating. This means they satisfy hunger with fewer calories than low-quality
foods: refined grains, fatty meats, sweets, and fried foods. The more you shift
the balance of your diet away from low-quality foods and toward high-quality
foods, the fewer calories will be required to fill you up.
So the next time an increase in training ratchets up your appetite, go ahead and eat more. But at the same time boost the overall quality of your diet. By doing so you will continue to get leaner, lighter, and faster without having to go hungry.