Losing as little as a five to 10 percent of body weight and maintaining that loss can significantly improve the health of obese patients by increasing glucose tolerance and lowering blood pressure and cholesterol levels. Therefore, if you are overweight or obese, you should seek medical help to lose weight as well as to maintain it. To be successful at achieving weight loss goals to improve your health, experts recommend losing weight a rate of no more than one to two pounds per week, and then maintaining that loss for six months before losing more. Maintaining weight loss can be more difficult than losing the weight to begin with, so long-term lifestyle change is key.

A 1999 study of 2,800 individuals who lost at least 30 pounds and maintained the weight loss for more than a year reported the following:

* about 55 percent had been involved in a formal weight loss program

* 20 percent succeeded with liquid diets

* 4.3 percent used medications

* 1.3 percent had surgery

* 81 percent reported that they exercised more often and more vigorously than with previous attempts

The good news is that burning off more calories than you’re taking in will cause you to lose weight. The bad news is, there’s no magic formula. Studies have found that if you lose the weight slowly, you’ll be much more effective at keeping it off, especially if you incorporate exercise into your routine and reduce other sedentary behavior, such as watching TV.

The safest way to lose weight is to eat a nutritionally complete diet that is moderate in calories and fat, add exercise to your daily routine and decrease sedentary activities. In some cases, for example, if your health is being immediately and severely compromised because of your weight, faster weight loss may be appropriate. In these cases, your health care professional may recommend drug therapy or surgery.

Changing Your Diet

The first element of treatment is changing your diet. Your health care professional should provide detailed guidance on the number and types of calories you should eat. But as a rule of thumb, if you take in about 250 calories per day less than is needed to maintain your current weight, combined with an exercise regime that burns an additional 250 calories a day, you will lose about a pound per week.

To determine how many calories your body needs to maintain its basic functions-known as your basal metabolic rate, multiply your current weight by 10. For example, a woman who weighs 200 pounds requires 2,000 calories per day to maintain bodily functions such as breathing and digestion. You need additional calories-about 30 to 50 percent more if you are moderately active-to provide energy for daily activities like walking, vacuuming, even sitting at the computer.

It’s difficult to determine exactly how many calories you need to maintain your weight at your current level of physical activity. You may want to take your basal metabolic rate and add about 10 percent if you’re relatively sedentary, 20 percent if you’re lightly active, and 30 percent if you’re moderately active, and then subtract the 250 calories to arrive at your new recommended daily total. A slightly more accurate method is to keep a detailed food diary over the course of a few days to a week during which you maintain your weight. Determine exactly how many calories you eat on an average day-several books and web sites provide calorie counts for thousands of different foods-and use that figure as a starting place from which you would subtract 250 calories.

After you’ve determined how many calories per day you should eat, you need to plan daily menus. A dietitian or nutritionist can help you plan menus that include the types and amounts of food you should eat, which, in most cases, should be based on guidelines developed by the federal government in its Dietary Guidelines and revised most recently in January 2005 (the newly revised Food Pyramid was released in April 2005). The guidelines emphasize calorie reduction as well as balance, moderation and variety in food choices, with a special emphasis on whole grain products, vegetables and fruits.

To satisfy basic nutritional needs, eat a variety of foods including low-fat dairy, healthy protein sources like chicken, fish, eggs, and soy products, vegetables and whole grains- and allow for an occasional treat. While you should try to cut back on excess fats and sugars, all foods and beverages can be consumed in moderation. As soon as you label a food as “off limits,” chances are you will crave and perhaps even binge on it.

The 2005 Dietary Guidelines recommend the following (based on a 2,000 calorie-per-day diet; to find the amounts that are right for you, visit the Food Pyramid website at www.MyPyramid.gov):

Meat and Beans (Protein)

* Eat 5 1/2 ounces of protein every day (vary your choices of meats, poultry, fish, beans, peas, nuts and seeds)

Fruits, Vegetables and Milk

* Eat sufficient amounts of fruits (2 cups daily) and vegetables (2 1/2 cups daily), while staying within your energy needs.