At Notre Dame, the number one reason students seek nutritional counseling is for weight loss. On occasion I’ll encounter a client who is reluctant to engage in increased activity or exercise out of fear of stimulating their appetite. They are worried if they exercise longer or harder, their appetites will be increased, therefore making weight loss even harder. So, is there truth in that? How much does exercise impact our appetites, and ultimately our weight loss goals?
We don’t know everything, but the discovery in 1999 of the appetite-stimulating hormone ghrelin helps shed some light. Most research suggests that vigorous exercise temporarily suppresses appetite. The appetite will soon recover, but usually not at a level to fully compensate for the energy expended during exercise. A 2016 study set out to examine the appetite response to either calorie restriction or increased exercise. The results showed that appetite perceptions increase robustly when food intake is reduced, but not when energy expenditure is increased via exercise. In conjunction, it was found that ghrelin (that hunger hormone), was higher during the food restriction trial than during the exercise trial. This hormonal response suggests that appetite is stimulated more so through a calorie-restricted diet than through physical activity. A different study looked at appetite perception, appetite hormones, and food intake responses to exercise. After a one-hour run, appetite perceptions and ghrelin concentrations were reduced and recovered shortly thereafter. Food intake at a subsequent buffet meal did not differ between those that exercised and those that didn’t.
All of this helps point to the conclusion that exercise is an important piece in weight management. Including exercise, even vigorous exercise, is part of a successful approach to weight loss. One need not worry about a heartier appetite when increasing exercise. See ya at the gym!