Regardless of how many calories you torched, working out will make you less likely to overeat post-sweat sesh
Sometimes, hitting the gym extra hard can feel like an excuse to splurge later (#afterthisweregettingpizza, right?). But according to a new study, intense exercise will actually make you want to eat less later in the day, which may explain your urge to reach for a green juice over a frapp with extra whip when you leave the gym. (Check out The Best Foods to Eat Before and After Your Workout.)
In the study, published in the journal Medicine and Science In Sports and Exercise, researchers in the United Kingdom looked at how intense exercise impacted hunger. Turns out, it was more effective at reducing calorie consumption than simply cutting calories alone.
They looked at the overall calorie consumption for two groups of people: The first created an energy (calorie) deficit by simply slashing their food intake, and the second created a calorie deficit by doing a moderate-intensity treadmill run for 90 minutes. They then presented each group with an all-you-can-eat buffet to measure how much they consumed (tough job!).
Surprisingly, the group who had just worked out consumed about one-third fewer calories than the group who had been dieting all day (663 vs. 947 calories) The researchers discovered two possible reasons why. When you exercise, the hunger hormone (ghrelin) decreases, while levels of the hunger-suppressing hormone (peptide YY) spike. When we restrict calories (or energy intake) through dieting, the opposite happens. (Psst... Read up on these 4 Nutrition Rules to Combat Running-Induced Hunger.)
The researchers hypothesize that this exercise-inducing effect has to do with blood flow to the stomach. "Since ghrelin is produced in cells within the stomach, a reduced blood flow to the stomach might possibly lead to reduced ghrelin in the circulation," says David Stensel, Ph.D., lead author on the study.
Previous studies by Stensel's team support this idea too. In one study, they found that vigorous intensity exercise (think running or an intense spin class) reduced the hunger hormone, but moderate intensity (like the speed of a brisk walk) did not produce the same effect.
What does this mean for your workout? Exercise intensity and duration are both important, says Stensel. Intense bouts of aerobic and anaerobic exercise (like a kickboxing class or an interval treadmill run) will both suppress your appetite. And the longer you exercise, the longer you'll experience this side effect.
So far, the researchers have only looked at these effects for the first two days following exercise, so they can't say for sure whether the hunger suppression lasts longer than that. But keep up with you regular workout plan, and you'll keep reaping the waist-whittling benefits. And there's be no reason for guilt after that occasional post-gym pizza! (Actually, Please Stop Feeling Guilty About What You Eat.)