Weight loss surgery may not only help severely obese people shed pounds, but it may also solve some of the most common health problems caused by obesity -- even if they remain overweight.

A new study showed that gastric bypass surgery reversed the progression of diabetes and, in most, eliminated high blood pressure within two years in severely obese men and women who had the procedure.

Researchers say these health benefits of gastric bypass surgery for weight loss were apparent even though the participants were still considered overweight or obese.

Two years after the procedure, about half of the participants reached a body mass index (BMI, measurement of weight in relation to height used to identify obesity) of 30 or less. Ten percent reached a BMI of 25 or less, which is considered normal.

A BMI of 25-30 is considered overweight, over 30 is obese, and more than 40 is considered severely or morbidly obese.

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Bariatric Surgery Solves Many Health Problems

In the study, researchers followed a group of 107 morbidly obese men and women who underwent gastric bypass weight loss surgery. The procedure involves reducing the size of the stomach and allows food to bypass much of the small intestine, where absorption of nutrients occurs.

Two years after the procedure, the participants had lost an average of 36 percent of their body weight with a 50 percent decrease in their fat mass.

Although most of the participants were still classified as obese, the significant loss of fat and body weight had resolved many of their most pressing health problems.

For example:

Before weight loss surgery, 83 percent of the participants had borderline to severe high blood pressure. Afterward, more than 96 percent had normal blood pressure levels and the remaining 4 percent had mild hypertension, which did not require the use of blood pressure-lowering medication. Before the procedure, 23 percent of the participants had a diagnosis of diabetes. Two years after the surgery, 88 percent of the people with diabetes had regained normal blood sugar levels. Insulin sensitivity increased by 150 percent among the participants after weight loss surgery. A gradual loss of sensitivity to the action of insulin to lower blood sugars leads to type 2 diabetes or prediabetes. Overall, the number of participants with at least one major risk factor for heart disease dropped from 100 percent to 19 percent in men and from 97 percent to 9 percent in women.

Researchers say the results show that many of the health problems associated with severe obesity can be resolved with significant weight and fat loss through gastric bypass surgery, even if obesity persists.

Read WebMD's "Weight Loss Surgery: Is It For You?"

By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCE: Valera-Mora, M. American Journal of Clinical Nutrition, June 2005; vol 81: pp 1292-1297.