Is there such a thing as a good time or bad time to eat? Will your body add pounds if you feed it at the wrong time, or will you binge if you miss the window of time to stave off a craving? Because everybody has a theory about when and when not to eat, we asked our team of nutrition experts to separate the myths from the facts and to define mealtime.

The Theory: Don’t eat carbohydrates after 8:00 P.M. because you’ll never burn them off.

The Reality: The rationale here is that, at night, our bodies won’t use up the fuel we eat because we’re not very active (in fact, we’re usually asleep). To some extent this is true. If we don’t use the calories we take in, they are temporarily stored in the muscles or liver, whether they come from carbohydrates, protein, or dietary fat. Luckily, the calories in/calories out ledger doesn’t close every night and start afresh the next day; you can use the calories the next morning. (You won’t experience weight gain unless you consistently take in more calories than you use.)

The Practice: “If you exercise after work, you should definitely refuel your energy stores with carbohydrates like grains, fruits, and milk products and not worry that it will end up as fat,” says Lori Marcotte, R.D., director of food and nutrition programs at the Center on Hunger and Poverty at Tufts University. “The key is,” says Susan Kleiner, Ph.D., R.D., nutritionist for the Seattle SuperSonics, “try not to eat for the last two or three hours before bed.”

The Theory: Eat constantly to keep your metabolism revved up.

The Reality: While a person’s metabolism (the rate at which the body uses food for energy) is determined by age, sex, height, weight, and amount of physical activity, it can be heated up by the “thermic effect of food.” When you eat, your body uses energy to process the food. However, this process only amounts to an extra 150 or so calories being burned per day.

The Practice: “Eat every two to three hours to stay anabolic [a state in which your body is consuming energy to build up things like protein], maintain constant blood sugar levels, and avoid feeling hungry and fatigued,” says Kleiner. “Having low blood sugar,” explains Marcotte, “can entice many people to overeat or grab sugary, high-fat snacks.” Of course, the best way to keep your metabolism running fast is to stay active and fit.

The Theory: Eat something in the morning to wake up your metabolism.

The Reality: Although just rolling out of bed will send a signal to your body to use energy, “the process of digestion and absorption [of breakfast] does increase your metabolic rate,” explains Kleiner. “Besides,” says Tracy Stopler Kasdan, R.D., president of the Nutrition E.T.C. consulting firm in Plainview, New York, “you need breakfast because it won’t take long for your body to use up any leftover calories from the night before and need a refueling.”

The Practice: Stopler Kasdan recommends eating a balanced breakfast that contains some carbohydrates (from fruit, juice, cereal, or toast), protein (from milk or eggs), and fat (from low-fat dairy products or margarine); it will take a while to digest and therefore will provide energy for several hours.

The Theory: Eat some fat early in the day to keep yourself from overeating later.

The Reality: Eating fat in the morning may help you feel full longer, but it won’t buy you immunity from cravings. “If you don’t eat early in the day, you are likely to overeat later due to hunger,” says Kleiner. “I wouldn’t say that having fat will keep you from overeating, necessarily, but it does help satisfy.”

The Practice: “Spread out your nutrients evenly throughout the day and try to combine carbs with protein and/or fat to slow down absorption,” says Kleiner. This will give you timed-release energy rather than a surge. You should be starting to see that it’s not only when you eat but also what you eat that makes the biggest difference in your diet. Here are the major points to remember.

“Eat five to six small meals, consisting of protein, carbohydrate and fat, per day,” says Stopler Kasdan.

Try to eat every few hours.

An hour or two before exercise, eat a combination of protein and carbs (200-250 calories total).

If you’re working out for an hour or more, use a sports drink for fluid replacement and an energy boost, suggests Kleiner.

After exercise, combine protein and carbs again (this time about 80 of carbs to 20 protein) within 15-30 minutes of finishing and again two hours later to enhance muscle recovery and development.