For some, there’s nothing like a vigorous workout to prepare yourself for a hearty meal. But in fact, the contrary may actually be true: Exercise can stifle hunger. New research points to the science behind how exercise — one type of exercise in particular — can curb the desire to eat.
A new paper published today in the Journal of the Endocrine Society by researchers at the University of Virginia (UVA) found that intense exercise modulates our sense of hunger, especially in women. The small study involving 14 healthy people looked specifically at the relationship between physical activity, perceived hunger, and a hormone that controls our appetite. The findings show that this type of workout can affect hunger and potentially aid in a healthy, long-term weight loss program.
The study looked at eight men and six women between ages 18 and 55. Participants completed three days of testing, in which they fasted the night before. At each visit, the participants performed either no exercise, moderate-intensity exercise, or high-intensity exercise. The researchers observed them for 3 hours each time, taking blood samples and administering surveys on appetite, hunger, satisfaction, fullness, and desire to eat.
Most crucially, the researchers used blood samples to track two molecules. One is lactate, which the body produces during exercise. Lactate levels in the blood serve as a measure of fitness, or how well a person can tolerate an intense exercise and for how long. The other is the hormone ghrelin, which comes from an empty stomach and signals to your brain when it’s time to eat.
The team found that appetite scores were the same between both types of exercise, and while men showed higher hunger scores during moderate exercise compared to vigorous, women had higher scores during moderate compared to no exercise. However, the women had significantly reduced ghrelin levels following high-intensity exercise. The researchers posit that there could be a lactate level that must be crossed in order to trigger ghrelin suppression.
While larger studies that dive into sex differences regarding lactate and ghrelin are necessary, this study offers an initial insight on how exercise can influence weight loss and the mechanisms through which that works.
“Exercise should be thought of as a ‘drug,’ where the ‘dose’ should be customized based on an individual’s personal goals,” said the study’s first author Kara Anderson, an endocrinology postdoctoral researcher at the University of Virginia School of Medicine, in a press release. “Our research suggests that high-intensity exercise may be important for appetite suppression, which can be particularly useful as part of a weight loss program.”
