In the largest and longest study to date of weight loss maintenance strategies, researchers at Duke University Medical Center found that personal contact -- and, to a lesser extent, a computer-based support system -- were helpful in keeping weight off.
"The results of this study send a strong signal to those who seem to believe that obesity is such an intractable problem that nothing can be done about it," says Dr. Laura Svetkey, professor of medicine at Duke and the lead author of the study. "Our research shows that is not true. A large majority of the participants in the Weight Loss Management study lost weight and kept weight off for two and one-half years."
Svetkey and researchers at four institutions around the country studied 1685 overweight or obese adults who were being treated for high blood pressure, high cholesterol, or both. Scientists asked participants to increase their activity level, reduce their calorie intake and follow the DASH diet (Dietary Approaches to Stop Hypertension) for a period of six months. The DASH diet emphasizes fruits, vegetables, low-fat dairy products and whole grains, and has been proven to lower "bad" cholesterol and blood pressure.
In the first phase of the study, participants attended 20 weekly group meetings with a trained interventionist who coached them on making these lifestyle changes. Only participants who lost at least nine pounds were admitted to a second phase of the study; 61 percent met that goal, with weight loss ranging from nine to 66 pounds.
In the second phase, 1032 participants were randomized to one of three groups: a self-directed control group, where they were left to their own devices to manage their weight; a personal contact group, where they received monthly coaching and support from a counselor assigned to them; or a computer-based, weight loss maintenance program that offered the same counseling that personal contact offered, but in a virtual, interactive format.
More than 70 percent of the participants weighed less at the end of the study than when they started. Those in the personal contact group were the most successful, with 77 percent maintaining some weight loss. The computer intervention group had a 69 percent success rate and the self-directed group had 67 percent.
"In addition, 42 percent of the personal contact group was able to maintain weight loss of at least 5 percent of their starting weight, an amount of weight loss that has clear health benefits," Svetkey said. "In the other groups, about 35 percent were able to maintain this much weight loss."
Overall, however, the effects of the interventions were modest. At the end of the study, the personal contact group had regained 3.3 pounds less than the self-directed group. Those in the computer-based support program fared almost as well -- at least for the first two years. After that point, the virtual intervention lost its edge, and by the end of the study, their efforts at maintaining weight loss were similar to those enrolled in the self-directed control group.
But Svetkey, director of clinical research at the Sarah W. Stedman Nutrition and Metabolism Center at Duke, points out that even modest success paves the way to major victory.
"We didn't set out to cure obesity, but we did want to offer participants a set of tools they could use to change their lives," Svetkey said. It's not easy to counteract all the forces around us that encourage us to overeat and be sedentary, but we think this study moves us in the right direction."
Svetkey stresses that every pound lost can lower blood pressure and risk of developing diabetes. "Our patients have shown that under the right conditions, long-term weight control is an achievable goal worth pursuing," says Svetkey. "It's also important to understand that it's not necessary to reach a normal weight to improve your health. The focus needs to be on changing a lifestyle and sticking to it. Every pound lost improves health."
Journal reference: JAMA. 2008;299:1139-1148
The study was funded by the National Heart, Lung, and Blood Institute. Svetkey says it its notable that, unlike most other weight loss studies, the Weight Loss Management study included a large number of African-American participants (38 percent) and large n numbers of men and women. Studies show that obesity is more prevalent among African-Americans and the consequences of obesity are more serious for blacks than whites.
Researchers from Duke who contributed to the study include Carmen Samuel-Hodge, Lillian Lien and Kathleen Aicher. Additional work came from scientists at The Kaiser Permanente Center for Health Research, Pennington Biomedical Research Center and Johns Hopkins Medical Institutes.
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