It doesn’t matter if I swim for an hour or do an easy 3-mile neighborhood run in the evening. I am usually famished afterward. I may literally work up an appetite, but I don’t want to undo my training and shovel in more calories than I just burned.
Plus, I always though that exercise is supposed to suppress appetite. So how does one fight the post-workout cravings and make your workouts work for you?
You need to focus on three areas: the type of exercise, its intensity and the time of day you work out.
Types of Exercise: Research has shown that both aerobics and weight lifting can suppress hunger by managing hormones that regulate appetite, specifically ghrelin and peptide YY, which increases and quells appetite (respectively). But a study from Loughborough University in the U.K. found that aerobics result in a greater suppression of hunger. If you fight post-exercise cravings, lace up your sneakers and break a sweat more often.
Intensity of Workouts: People who exercise at a mild or moderate level (if you can hold a conversation, it’s too light) tend to experience more cravings afterwards. The reason: Your body recognizes spent calories and wants to replace them, even if you’re overweight.
Intense exercise, however, the kind that makes you huff and puff and sweat and pushes you to near exhaustion, has the opposite effect, says Susan Kleiner, Ph.D, R.D., author of "Power Eating, 4" (Human Kinetics, 2013). “When you push up the intensity, you drive up your metabolic rate and burn more calories,” notes Kleiner. “It places the body in a high stress environment like a fight or flight response where adrenaline surges and your body is on high alert. It doesn’t worry about replenishing calories.”
So, you need to pick up the pace. How much intensity is enough? Kleiner suggests interval training — either running or cycling — as the best metabolic booster. In interval training, you maintain a burst of intense anaerobic exercise for 1-2 minutes — where you almost can’t go any longer or hardly speak — followed by a rest period of equal time length, where you still move, but slow to a pace where you can quickly recover. Repeat this back and forth cycle of intense-rest-intense-rest for 20 minutes total.
If intervals are beyond your current fitness level, you can experience a similar reaction from a brisk walk. Researchers discovered that 60 minutes of continuous walking at a constant pace (about 4.5 mph) did not increase circulating levels of the appetite hormone ghrelin. You have to exercise longer compared to intervals — 1 hour versus 20 minutes — but the constant movement can have the same appetite-controlling effect.
Time of Day: Mornings tend to be better. New research from BYU found that 45 minutes of moderate-to-vigorous exercise (the kind you need) in the morning can reduce your motivation for food. Scientists measured the neural activity of women while they viewed food images both after morning exercise and a morning without. They found attention response to food decreased after the brisk, early workout.
Of course, you need to eat something afterwards to replenish lost carbs and fluids, and feed muscles protein. But you also want to avoid a feeding frenzy. The solution: a liquid snack. “It can help refuel muscles and support recovery, but also delay hunger spikes until regular meal time,” says Kleiner. A protein shake can do the trick. Stick with a recipe of 2:1 ratio (carbs to protein) with at least 25 grams of total protein.
Here’s a simple recipe from Kleiner: 1 cup nonfat milk; ¼ cup calcium-fortified orange juice; ¼ cup frozen strawberries; 14 g whey protein isolate. Blend until smooth.
No time to mix a protein drink? Just down about 2 cups of low-fat chocolate milk. A study from James Madison University found it was as effective as commercial high-carb energy drinks in lowering muscle fatigue and soreness after intense training. And who doesn’t want to reward themselves with chocolate?