You want to exercise more in 2017 but you’re worried that the increased activity will stimulate your appetite causing you to consume more calories than you burned.
Don’t cancel that gym membership just yet.
Contrary to what you might think, there is no evidence to support the notion that working out makes you hungry. Actually, the opposite appears to be true: exercise decreases food cravings. And that’s great news for exercisers looking to not only shape up but slim down.
“Most studies show that exercise itself really doesn’t make you hungrier,” says Martha Henley, a registered dietitian with Christiana Care’s department of weight management.
So what keeps you from going on a post-gym food bender? A 2013 study from the International Journal of Obesity found a relationship between intense physical activity and decreased levels of ghrelin—the hormone that fuels hunger—and higher blood sugar levels—which can stave off hunger pangs.
Moreover, researchers in the UK found that exercise was more effective at reducing calorie consumption than simply cutting calories alone. The study published in the March issue of Medicine & Science in Sports had two groups of subjects reduce their daily calorie totals—one by eating fewer calories and the other by exercising to burn off the calories.
Surprisingly, they found that ghrelin spiked in subjects who dieted all day, making them want to eat more. But there were no ghrelin spikes in those who exercised without dieting. In fact, at the shared all-you-can-eat buffet table, they consumed almost 300 calories less.
Researchers hypothesize that this exercise-induced effect has to do with blood flow. Since ghrelin is produced in cells within the stomach, the reduced blood flow to the stomach during exercise might lead to reduced ghrelin in circulation.
Research also suggests that exercise can change how our brains respond to food cues. A 2012 study from Brigham Young University found that the fitter you become, the less likely you are to crave food after exercise. The study monitored the brain waves of 30 volunteers who were shown food pictures after they’d been sitting for an hour and again after they exercised for an hour. Surprisingly, it was the sitters’ brains that lit up at the sight of greasy and sugary foods, while the exercisers’ did not.
Experts maintain that the relationship between exercise and appetite is a complex one that depends on a variety of biological and psychological factors. If you’ve just finished an intense session and still feel like downing an entire pizza, it could be dehydration. “A lot of people confuse thirst with hunger,” says Henley.
Moreover, actual food intake may be influenced by overestimating the amount of calories burned to things like the “halo effect:” wanting to be rewarded for all your hard “work.” Research shows that those factors occur more often in those individuals who are new to exercise and whose bodies and brains haven’t gotten used to the workout habit yet.
Henley advised clients to consume protein and healthy carbs to take the edge off any post-workout hunger pangs. If it’s close to your regular mealtime, go ahead and eat as you normally would. If it’s something sweet that you’re craving, stick with fruit. “Fruit is one of those carbs that’s going to be hard to overeat,” she says. “It’s hard to eat three or four apples.”