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It's hard to lose more than 1 pound a week without cutting back on calories or increasing exercise. Losing a half pound to 2 pounds a week and keeping the weight off is best done by eating healthy foods in moderate amounts and exercising most days of the week. Talk with your healthcare provider about weight loss. Ask for information on how to choose a safe weight-loss program.

No product can bring about permanent weight loss. Most diets end in failure because people are unwilling to change their lifestyle for the long term. Instead they want a quick fix. Healthy, doable weight loss is 1 to 2 pounds a week. Any more than that without a healthcare provider's supervision may not be safe. No product that is worn (rings, earrings, shoe inserts) or rubbed on the skin can cause permanent weight loss.

With the ketogenic diet, you eat a low-carbohydrate, moderate-protein, high-fat diet. People like this diet because they get to eat "forbidden" high-fat foods, such as bacon cheeseburgers, steak, and cheese omelets. But by limiting fruits and vegetables, you may not get the vitamins, minerals, and other essential nutrients you need. Talk with your healthcare provider before starting any diet.

These diets overwork your kidneys and can cause dehydration, headaches, and bad breath. They also can make you feel nauseous, tired, weak, and dizzy. On these diets, you lose water because your kidneys try to get rid of the excess waste products of protein and fat that your body makes. A buildup of these waste products in your blood can cause your body to produce high levels of uric acid. Uric acid is a risk factor for gout, which is a painful swelling of the joints, and kidney stones. This condition can be risky if you're pregnant or have diabetes.

Low-fat or nonfat foods, particularly snack foods, may still have plenty of calories. These foods often have extra sugar or other ingredients added to make them taste better. Sugar, extra flour, and thickeners all have calories, which can add up if the foods are eaten in excess. The number of calories in a food depends on the amount of carbohydrate, protein, and fat it contains. Carbohydrate and protein have about 4 calories per gram. And fat has more than twice that amount, at 9 calories per gram. Fruits and vegetables are good snack options. Most are naturally low in fat and calories.