Dietary counseling has resulted in weight loss of approximately 6 percent of initial body weight (approximately 10-15 pounds) after one year, compared with people not involved in formal weight loss programs.
The authors analyzed 46 trials that included 6,386 people who were participating in dietary counseling-based weight loss programs and 5,467 people not involved in formal weight loss programs. Programs with more frequent meetings and greater calorie restrictions tended to produce greater weight losses over time.
Approximately half the weight loss remained at three years, but almost none of the weight loss remained at five years. Obesity-related problems are among the most serious health problems facing U.S. adults. Nearly two-thirds of U.S. adults are overweight (BMI over 25), and approximately half of overweight adults are obese (BMI over 30).
Overweight and obesity are known risk factors for diabetes, coronary heart disease, high blood pressure, stroke, hypertension, degenerative joint disease of the knees and hips, and some forms of cancer, among other conditions.
Dietary and lifestyle modifications are the primary methods for treating and preventing obesity but the net effect of dietary counseling for weight loss had not been published until now.
"We did not know how much weight people lost on average through weight loss programs or how long it took them to gain it back," said Michael L. Dansinger, MD, MS, one of the study authors and a physician at Tufts-New England Medical Center's Division of Endocrinology, Diabetes and Metabolism and Assistant Professor of Medicine at Tufts University School of Medicine. "This study shows that lifestyle changes need to be for the long-term.
"Moderate weight loss -- 10 to 20 pounds -- has a dramatic effect on most of the medical problems caused by obesity. Diabetes, cholesterol, blood pressure, and stroke risk all appear to be nicely reduced by a moderate amount of weight loss. People don't have to lose 100 pounds to make a big difference in their health."
The study, "Meta-analysis: Effect of Dietary Counseling for Weight Loss," appears in the July 3, 2007, issue of Annals of Internal Medicine.
To reach Dr. Dansinger, contact Catherine Bromberg, Tufts-New England Medical Center (617-636-0206 or CBromberg@tufts-nemc.org).