All of these steps help. Low-fat diets can cut your risk for heart disease and other problems. But experts say it's not the type of the diet that affects weight loss. It's how many calories you take in and how many you burn. Calorie-burning exercise is vital. But it won't work alone. If a 120-pound woman walks briskly for an hour, she burns about 200 calories. But you must give up 500 calories a day to lose 1 pound a week.

If you eat the same dinner at 6 p.m. or 10 p.m., it won't matter weight-wise. But emotional eating (such as downing a bag of cookies while depressed) often occurs at night. You'll also feel more satisfied and energetic if you eat during the day.

This diet has been around for a century, going in and out of style. It’s really a low-calorie diet in disguise. A high-protein diet burns no more fat than a healthier, low-calorie diet. Carbohydrates aren't more fattening than protein. Both fat and protein have 4 calories per gram. Fat has 9 calories per gram. And despite diet claims, there's no proof that eating carbs makes you store more fat. It's excess food of any kind that packs on weight. Do these diets keep you from feeling deprived? Experts say yes, because they let you eat foods like butter and cheese. But they limit your choices. Over time, they cause food boredom. They can leave you tired and nauseated. And they can make you constipated.

High-fat food like ice cream tastes great, but just half a cup has 230 calories. It goes down fast and has low "satiety." This means you get hungry again quickly. Two carrots are about 70 calories. They make up a bulky, high-fiber snack. This snack fills the stomach in a lasting way. And it raises blood sugar slowly. An ounce of pretzels offers not much bulky fiber. And it raises blood sugar too fast. The orange juice (100 calories) is a setup for dieters. People tend not to swap drink calories for food calories. This is because the fullness doesn't last. A tablespoon of peanut butter offers a satisfying protein. But you have little to chew on. You can add it to celery sticks for a filling combo.

But some fat is good for you. You need polyunsaturated fats for certain body functions. Omega-3 fats in fish are healthy for your heart. So are monounsaturated fats. These fats are found in nuts and healthy oils. Only saturated fat is labeled "bad." This type of fat is found in dairy products and red meats. Fat doesn't burn as easily as carbohydrates during exercise. This is because it takes more oxygen to burn fat. But that doesn't matter. Your workout burns both. Just make sure to exercise at a level that lets you breathe comfortably.

Experts say that fad diets fail because they don't teach you how to manage weight for the long term. When you see you can't stick to a fad diet, you will likely go back to eating the way you did before. The National Weight Control Registry is a record of people who lost 30 or more pounds and kept it off more than a year. The Registry offers clues to what really works. It notes that:

• 98% of people say they changed how much food they ate to lose weight.
• 94% got more exercise. The most common form of exercise was walking.
• Registry members keep their weight off in several ways. Most say they eat a low-calorie, low-fat diet. And they get a lot of exercise.