Ravenous After Exercise? It Might Be Your Workout Timing

Timing Is Everything: You’ve heard that before, but did you know it may apply to your workouts, too? If you exercise to support a healthy weight, timing may play a big role in your success. New research investigates whether the time of day — and whether you’ve eaten beforehand — also affects how hungry you become and how much you eat afterward.

The Study: Researchers recruited 35 healthy young adults for a randomized crossover trial. Participants completed 30-minute treadmill runs under different conditions: in the morning after an overnight fast or in the evening after either a 12- or 6-hour fast. A subgroup completed the same workout in the morning or evening after eating. After each workout, researchers measured appetite, calories consumed at a meal, and total food intake over the next 24 hours. Evening fasted exercise led participants to eat about 400 more calories immediately afterward and roughly 550 more calories over the next day compared with morning fasted exercise. Those who exercised in the evening, fasted or not, experienced greater hunger and appetite.

The Takeaway: Morning workouts may be less likely to trigger “compensatory eating” than evening sessions, though there are other factors to consider, too: for instance, the hormone ghrelin, which stimulates hunger, naturally rises in the later hours of the day.

Keep in Mind: This was a small study of healthy young adults completing 30-minute runs. The findings are intriguing, but one thing remains true: the best time to exercise is the time you’ll show up consistently.