The one-year intensive weight loss and physical activity intervention involved 130 severely obese (class II or III) adult participants without diabetes.
One group was randomized to diet and physical activity for the entire 12 months; the other group had the identical dietary intervention but with physical activity delayed for 6 months.
Although both intervention groups lost a significant amount of weight at 6 months, the initial-activity group lost significantly more weight in the first 6 months compared with the delayed-activity group.
Weight loss at 12 months, however, was similar in the 2 groups.
However, the reduction of waist circumference, visceral abdominal fat, hepatic fat content, blood pressure, and insulin resistance was greater with the initial-activity gtoup.
The researcher conclude that intensive lifestyle interventions using a behavior-based approach can result in clinically significant and meaningful weight loss and improvements in cardiometabolic risk factors in severely obese persons. They recommend that physical activity should be incorporated early in any dietary restriction approach to induce weight loss and to reduce hepatic steatosis [fatty liver] and abdominal fat.
B. H. Goodpaster, J. P. DeLany, A. D. Otto, L. Kuller, J. Vockley, J. E. South-Paul, S. B. Thomas, J. Brown, K. McTigue, K. C. Hames, W. Lang, J. M. Jakicic. Effects of Diet and Physical Activity Interventions on Weight Loss and Cardiometabolic Risk Factors in Severely Obese Adults: A Randomized Trial. JAMA: The Journal of the American Medical Association, 2010; DOI: 10.1001/jama.2010.1505