The new thinking on nighttime eating

We’ve heard it a thousand times, a million different ways: Nighttime calories will make you fat. Stop eating after dinner to avoid packing on the pounds. If you want to lose weight, no food after 7 p.m. (thanks, Oprah).

The reason: A recent flurry of research has established a link between eating at night and weight gain. In a 2009 study from Northwestern University, mice that were fed high-fat foods when they should have been sleeping gained significantly more weight than those given the same exact diet during waking hours. Researchers at the Salk Institute for Biological Studies report that evening snacks might promote weight gain by knocking regulatory genes in the liver—a key metabolic organ—off its 24-hour rhythm, possibly disrupting your ability to burn sugars and fats effectively.

But the truth is that after-dinner snacking can actually be good for your weight and health, but with this very important caveat: It must be done right. “Eating small, healthy meals throughout the day can help keep your metabolism burning strong—even if it’s right before bed,” says Jeffrey Morrison, M.D., C.N.S., founder of the Morrison Center in New York City and member of Equinox’s health advisory board. “Studies have shown that it’s not eating before bed that contributes to weight gain, it’s what you’re consuming that matters.”

If night bites are your thing, here’s how to make them work for you.

Zero in on specific nutrients: Evening snacks should top off at 150 calories, says Melissa Wood, a certified health coach with The Morrison Center. "Look for complex carbs, which don't raise your blood sugar and contain healthy fiber,” says Wood. She recommends: a small protein shake with almond milk; two hard-boiled eggs; a bowl of blueberries with almond milk; half an apple with a scoop of almond butter; or a small bowl of fiber-packed unsweetened brown rice cereal or quinoa. Complex carbs, fiber and protein take longer to digest, so you’ll be satisfied—and less likely to reach for junk food thereafter.

Use it to fuel a workout: The protein in these snacks can do more than keep your metabolism revved—it also stimulates muscle growth, making the next morning an ideal time to hit the gym, Dr. Morrison says. Dietary protein helps you build muscle effectively during your workouts, and the leaner you are, the more calories you burn throughout the day.

Time it right: The perfect time for your evening nibble? About an hour before bed, which allows your food to digest properly so it actually supports quality sleep, rather than interfering with it. “When we eat, the metabolic hormone leptin sends signals of satiety through the body and ghrelin contributes to the feeling of being full,” Dr. Morrison says. “People with insomnia have found that eating a healthy snack before bed keeps hormones in balance and helps them sleep through the night.”