The relationship between exercise and weight loss is well-known – in general, the “formula” for weight loss is understood to be that calorie expenditure (through exercise or other activity) should be greater than calorie intake for weight loss to occur. But how does exercise affect that calorie intake – specifically, your appetite?
Exercise and Appetite Hormones
It has been found that exercise can curb appetite by having an effect on hormones related to appetite. Ghrelin is a hormone that increases appetite and peptide YY suppresses appetite. Research has found that aerobic exercise can suppress ghrelin while increasing peptide YY. Anaerobic exercise, such as weightlifting, can also suppress ghrelin but has little effect on peptide YY.
Duration and Intensity Matter
According to the American Physiological Society, aerobic exercise can have an effect on appetite after about 60 minutes of activity while it takes about 90 minutes of anaerobic exercise to affect appetite suppression. The intensity of the workout also matters – more rigorous and weight-bearing exercise reduces appetite more than moderate and light, non-weight-bearing exercise.
Exercise, Appetite, and Weight Loss
The effects of exercise on appetite suppression are strongest directly after a workout. They can last up to 24 hours, especially for individuals who exercise more strenuously. Besides influencing your appetite, exercise can also change the way you think, particularly about food and eating. People who exercise may be more inclined to choose healthier eating options than those who don’t because they feel better about themselves. If weight loss is the goal, the effects of exercise on appetite suppression should not be depended on. Rather, regular exercise paired with healthy eating remains the best and healthiest option for long-term weight loss.
It should be noted that appetite suppression is not the same for both women and men – it seems to be easier for men to feel the effects and for longer than women, meaning that women can more easily get their appetite back. Also, there is always the risk of individuals adopting the thinking that they’ve “earned” a treat following a workout, or that the workout either has already or will burn off those extra calories anyway. This thinking is dangerous because oftentimes, the calorie expenditure is overly estimated, meaning that any progress made during a workout can easily be undone. Low-fat meal options and foods with a low glycemic index are fairly safe for a pre- or post-workout snack.