Need one good reason to lose weight? Your heart.

Want six other good reasons? Diabetes, stroke, arthritis, cancer, gallstones and sleep apnea.

Although peeling off pounds won't guarantee that you'll escape these diseases, it will give you much better odds. Or it could help you stop or cut back on medications to control such disorders as high blood pressure or diabetes.

Dropping just 10 percent of your body weight (for example, 18 pounds if you weigh 180) can put you on the path toward a longer and healthier life, especially if you integrate regular physical activity into your routine. Studies show that blood pressure declines, along with blood glucose levels, even in individuals who are not hypertensive or diabetic.

To retain the health benefits, keeping the weight off is most important. It's best to lose weight slowly - no more than 2 pounds a week - and make permanent lifestyle changes, including regular exercise and a healthy diet.

Even losing 5 percent of body weight helps, says Dr. Laurence Sperling, director of preventative cardiology at the Emory Clinic.

``Modest weight reduction can make a huge difference for your heart,'' Sperling says. ``People who have to lose 50 pounds may see it as an insurmountable mountain, and it's overwhelming to them. But for most people, even 5 to 10 pounds will have a significant benefit. It's really modest ... weight loss that appears to be critical to improve blood pressure, lower blood cholesterol and improve the body's ability to handle blood glucose.''

Obesity causes an estimated 300,000 premature deaths per year among Americans and is the second leading cause of preventable death, after smoking. More than half of U.S. adults are considered overweight, and 22 percent of them are obese.

But despite all the scientific studies connecting weight loss and health, the magic motivator seems to be looking better at poolside or the beach.

``People are more concerned with the cosmetic benefits of losing weight,'' observes Dr. William Dietz, director of the division of nutrition and physical activity at the Centers for Disease Control and Prevention. ``And generally, physicians don't counsel patients when they are overweight about the health risks. We know that when they do, patients are more likely to control their weight.''

Obesity is also a co-culprit in some cancers. It may increase the risk of breast, uterine, ovarian and gallbladder cancer in women and colon and prostate cancer in men, according to the American Cancer Society.

And weight control is vital in avoiding Type 2 diabetes; estimates are that 75 percent to 95 percent of Type 2 diabetes cases are linked to being overweight. Asthma, sleep apnea, osteoarthritis and gallbladder disease have also been linked to excessive weight.

For Chris Jernigan, losing 50 pounds has helped him get his z's. The 38-year-old Marietta, Ga., computer support specialist was diagnosed with sleep apnea last fall. He enrolled in the Weight Reduction Clinic at Northside Hospital, a yearlong program that uses weekly nutrition, exercise and health psychology classes to help people make permanent changes in their lifestyles. Maintaining the weight loss is emphasized.

``Now that I've lost weight, the apnea has improved,'' says the 6-foot-1 Jernigan, who'd like to slim down more, from his original 274 pounds to 200. He doesn't want to end up like his parents, who have both suffered heart attacks. ``My blood pressure was elevated, and my cholesterol was getting up there,'' he says. ``But now my resting heartbeat has gone down with exercise.''

Sedentary people with high blood pressure or high blood sugar can see beneficial changes without dieting if they move their bodies more.

``Any activity at 30 minutes a day - and it can be moderate, such as gardening, biking, walking - at least five times a week helps,'' Dietz says. ``Additionally, physical activity seems to play a very important role in weight maintenance after losing weight. About an hour of walking every day will maintain weight losses.''

Keeping weight off requires dedication. Prepackaged diet products may give you a jump start in losing 10 of the 20 or 30 pounds you want to drop, but you can't eat those foods forever.

``People can't learn on their own if they come to rely on prepackaged foods,'' says Kim Glenn, a registered dietitian and the coordinator of a weight-reduction clinic in Georgia. ``They need to learn how to prepare their own foods and how to eat out. And you need to exercise. You can't lose weight and keep it off without exercising. ... You need a lifestyle change.''

What should you weigh?

The body mass index, or BMI, which uses a height-weight ratio, determines a person's status of underweight, normal, weight, overweight or obese. A BMI under 18.5 is underweight, 18.5-24 is normal, 25-29 is overweight, and 30 and above is obese.

To calculate your BMI: Multiply your weight in pounds by .45 to get kilograms; convert your height to inches; multiply that number of inches by .0254 to get meters; square that number (multiply it by itself); divide this into your weight in kilograms, and the answer is your BMI.

Or visit the National Institutes of Health Web site for BMI calculations and information on risk assessment and losing weight: http://www.nhlbisupport.com/bmi/bmicalc.htm

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Related MEDLINEplus Pages:

• Heart Diseases (General)
• Obesity
• Weight Loss/Dieting