The honest-to-goodness truth about how to keep your weight under control.

Myth No. 1: 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. That's why strength training is even more important if you're on a weight-loss mission.

Myth No. 2: Eating Protein and Carbs at Different Meals Will Help You Lose Weight
The theory: Protein and carbohydrates require different enzymes for digestion; if you eat the two separately, you improve digestion and further weight loss.
The reality: Your digestive tract can handle a variety of food groups at the same time. There is no proof that eating protein and carbohydrates separately aids digestion or weight loss. Indeed, it's healthier to combine protein and fiber-filled carbs than to separate them—they fill you up the most and give you the most energy. Also, some of the best foods for you—nuts, seeds, legumes—are made up of both protein and carbohydrates.
The best advice: Eat protein along with carbs, but choose with care. The best protein choices are lean meats, poultry, low-fat dairy products, and tofu, because they have little (if any) saturated fat. The best carbs are whole grains, fruits,
and vegetables.

Myth No. 3: To Lose Weight, You Need to Cut Calories Drastically
The theory: Eat much less; weigh much less.
The reality: Sure, if you subsist on 1,200 calories a day, you'll take off weight, but it won't be for long. Consider an analysis of 31 studies of long-term diets, where the diets averaged 1,200 calories a day. The report found that within four to five years the majority of dieters regained the weight they had lost. Psychologically, it's difficult for people to adhere to strict diets over a long period because they feel deprived and hungry.
The best advice: Don't starve yourself. If you want to lose weight and keep it off forever, you need a modest calorie restriction that you continue and never stop. But what's the right number of calories for you? Use this easy formula: First, find your activity level below ("And Your Number Is..."). Multiply your weight by the number indicated. (If you fall between two categories, adjust the number by adding a point.) The result is the number of calories you need to maintain your weight. Let's say you weigh 135 pounds and do light exercise one to three days a week. Multiply 135 by 13.5 to get, approximately, 1,800 calories. To drop some pounds try cutting out 250 calories a day. In a year, if you make no other changes, you could be 26 pounds lighter.

And Your Number Is...
You exercise: Almost never
Multiply your current weight by: 12

You exercise: Lightly, one to three days a week
Multiply your current weight by: 13.5

You exercise: Moderately, three to five days a week
Multiply your current weight by: 15.5

You exercise: Vigorously, six to seven days a week
Multiply your current weight by: 17

You exercise: Vigorously, daily, and you have a physical job
Multiply your current weight by: 19

Myth No. 4: Eating Fat Makes You Fat
The theory: Fat has nine calories per gram, whereas carbs and protein have only four per gram, so to lose weight you have to avoid fat.
The reality: Fat is not the enemy. Although fat-laden products can be full of calories, a modest amount of fat may help you feel full (so you eat less overall) and make healthy foods, like vegetables, taste better (so you eat more of them). Fat also helps with the absorption of certain vitamins.
The best advice: Eat fat, but don't go overboard. Choose monounsaturated and polyunsaturated fats, found in liquid oils such as canola, safflower, and olive; most nuts; and fish. These fats don't raise blood cholesterol levels and may reduce your risk of cardiovascular disease. Limit or avoid saturated fats, found mainly in beef and dairy products, and trans fats, which are in a lot of packaged foods, fried fast foods, and margarine. These are less healthful than good fats, as they increase the risk of heart disease.