Among the many kinds of advice given to those who are trying to lose weight, exercise usually ranks just below diet. But just as weight-loss advice can be contradictory and confusing, so too are the recommendations for exercise. No one disputes the benefits of physical activity on everything from improved digestion to better cognition. The adverse effects of ignoring the prescription to move ones body are just as compelling: no exercise equates to bad sleep, bad bones, and bad mood, among other unpleasant symptoms.
But many dieters and weight maintainers are reluctant to exercise because they fear the effect on their hunger. Exercise seems like an ineffective, and indeed unworkable, way of losing weight when post-exercise appetite may lead to eating many more calories than those worked off. Anecdotal reports by dieters of feeling ravenous after a stint on the treadmill or weekly Zumba class supports the erroneous belief that exercise while dieting should be avoided to prevent overeating.
Curiously, highly-trained athletes (who, of course, don’t have to worry about their weight) are the least likely to want to eat after their highly intense exercise routines are completed. In a study published a few years ago on appetite among female athletes, the scientists found that intense exercise actually decreased subjective hunger. Moreover, ghrelin, the hormone in the gut and blood that regulates hunger, was decreased and another hormone that shuts off appetite, increased. (“No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women,” Howe, S., Hand, T., Larson-Meyer, D., Austin, K. et al Nutrients, 2016; 8 ) The same effect had been found earlier in studies carried out with male endurance athletes.
Since most of us are not likely to devote a good portion of our lives to training for competitive athletic events, we cannot rely on this for suppressing appetite after exercise. However, it seems that even unfit obese men may also experience a decrease in hunger after intense exercise, at least for 30 minutes after the exercise session completed. Whether they overate several hours later was not reported. (“The Effects of Concurrent Resistance and Endurance Exercise on Hunger Feelings and PYY in Obese Men,” Asrami, A., Faraji, H., Jalali, S., International Journal of Sport Studies, 2014 4; 729-)
But one may ask: what is wrong with being hungry after physical activity? Isn’t hunger a natural and inevitable response of the body after calories are used up? A Food Network show featuring life on a ranch in some unnamed cattle-raising part of the country often features recipes for the “hungry” family and ranch hands after a day of especially hard work. It would be absurd for the workers to avoid physical labor just because they are very hungry when they return home to eat a substantial meal.
But most of us have traveled far from the natural progression of physical activity to hunger to eating to a return of energy, and thus being able to work again. The “I am so hungry that I could eat a horse” (or whatever animal comes to mind) statement after hours of manual labor or recreational physical activity seems to many like a prescription for weight gain, rather than the way nature intended us to feel.
But it is not. Hunger is natural. The hormones causing us to want to eat are there to make sure we do so in order to live. If hunger disappears, as is the case for some with late stage Alzheimer’s disease, the individual will not survive unless others make sure to feed the patient.
In short, we should stop being afraid of being hungry. Hunger means our bodies need food the way being thirsty means our bodies need water. How we satisfy our hunger is what we have to improve if we want to stop gaining weight and begin to lose it. Just as we could, but should not, satisfy our thirst by drinking gallons of champagne or sugary sodas; we should satisfy our hunger not by consuming junk food, but by eating foods that not only supply calories (to replace those used up in exercise) but also needed nutrients into our bodies.
Dieters are told to try to eat fewer calories than needed so the calories in their stored fat will be mobilized to make up the difference. But unless the dieter goes on a drastically low-calorie diet, or a diet that eliminates certain categories of foods, it is possible to eat less, satisfy hunger, and still lose weight. We often eat beyond feeling full, that is, beyond the cessation of hunger; this is why we eat dessert. If eating stops when hunger disappears—even if all the food has not—weight can be lost.
Should you eat before or after exercise? It depends on your body. Some cannot exercise after eating and will eat breakfast after, rather than before, working out in the morning. Others find that they don’t have the energy to play tennis or go hiking unless they have eaten. Therefore, they will eat enough to give their muscles fuel for their workout, but not so much that they feel too stuffed to move.
Sometimes during long bouts of exercise, such as a long bike ride or hike, the first sign that the body needs food is not hunger but fatigue. I remember once when I was cross-country skiing all day, I become too exhausted to move my skis up a hill to get back to the lodge. As I stepped outside the track to let a woman behind me pass, she handed me an energy bar. “You need food,” she said. “Eat this.“ She was right. Within a few minutes I felt my fatigue lift, and I was able to continue moving.
We are told to be in touch with our bodies. Exercising, being hungry, and eating healthfully are excellent ways of communicating with ourselves.