Myth No. 1: Don’t eat after 8 p.m.

The Theory: You burn up the food you eat earlier in the day, while late-night calories sit in your system and turn into fat.

The Reality: Calories can’t tell time. “Your body digests and uses calories the same way morning, noon, and night,” says Mary Flynn, Ph.D., a research dietitian at the Miriam Hospital, in Providence. They may sit around a little longer if you eat, then lie on the couch and watch Letterman, but when you move around the next day, your body will dip into its stores. That said, there are other solid reasons to avoid late-night snacking, not least of which is that snacks you grab when you’re tired tend to be unhealthy ones.

The Best Advice: If you often unwind before bed with a bowl of ice cream or buttered popcorn, try cutting the snack out. The calories saved may be enough for you to lose a few pounds a year. If you’re hungry, “eat something on the light side, like a piece of fruit or some cereal with milk,” says Ellie Krieger, a registered dietitian and the author of The Food You Crave (Taunton, $28., www.amazon.com). Night eaters tend to overeat (which leads to weight gain no matter when it’s done) because often they’ve been skimping during the day and come home famished. Being so hungry that you grab whatever is at hand means you’re more likely to make poor choices. “Don’t go longer than about five hours without eating,” says Jo Ann Hattner, a registered dietitian and a nutrition consultant in San Francisco. Just be careful to keep your meals and snacks small.

Myth No. 2: Eating small, frequent meals boosts your metabolism.

The Theory: If you keep adding small amounts of food to your fire (the fire being your metabolism), you will keep it going strong and burn more calories overall.

The Reality: Food intake has a negligible effect on metabolism. Some foods, including those with caffeine, may slightly and temporarily increase metabolism, but the effect is too small to help you lose weight. What most affects your basal metabolic rate (BMR), the rate at which your body burns calories at rest, is body composition and size. More muscles and bigger bodies generally burn more calories overall.

The Best Advice: Build up your muscles. A pound of fat-free tissue burns about 14 calories a day, while a pound of fat burns just two to three calories. And while that difference may not sound like a lot, it will certainly help over time. Remember, too, that when you lose pounds, part of that weight is muscle, warns Liz Neporent, an exercise physiologist and the president of Wellness 360, a New York City–based corporate-wellness-consulting company. That’s why strength training is even more important if you’re on a weight-loss mission. Try the seven-exercise Muscle Maintenance Workout. And if you hate lifting weights, you can instead maintain your muscles by going to a Pilates, body-sculpting, or power-yoga class two to three times a week.