| Research at PennThe study, to be published in the May 22 issue of the New England Journal of Medicine, was led by Gary Foster, PhD, associate professor of psychiatry and clinical director of Penn's Weight and Eating Disorders Program. Samuel Klein, MD, of Washington University in St. Louis and James Hill, PhD, and Holly Wyatt, MD, of the University of Colorado were the lead investigators at the other centers. The study investigated 63 obese men and women who were an average 44 years of age and weighed an average 216 pounds.
All participants met with a registered dietitian at zero, three, six and 12 months. Those in the Atkins group were given a copy of "Dr. Atkins' New Diet Revolution" and asked to follow the diet as described. The conventional diet group was given instructional materials on a 1,200-to-1,500-calories/day (women) or 1,500-to-1,800-calories /day (men) diet that consisted of 60 percent carbohydrate, 25 percent fat, and 15 percent protein based on the USDA food guide pyramid. Atkins participants lost an average of 14.7 pounds compared with 5.8 pounds in the conventional group at three months, 15.2 pounds versus 6.9 pounds at six months, and 9.5 versus 5.4 pounds at 12 months. At one year, Atkins participants had greater increases in HDL cholesterol (18 percent versus 3 percent) and greater reductions in triglycerides (28 percent versus 1 percent) than did those following a conventional diet. Neither group showed changes in LDL (bad) cholesterol at one year.
"Obesity is a national public health problem, and we need to evaluate alternative weight loss approaches aggressively," Foster stated. "Widely recommended low-carbohydrate approaches may be premature, but our initial findings suggest that such diets may not have the adverse effects that were anticipated. The real issue is whether low-carbohydrate approaches help patients maintain their weight loss better than conventional approaches. It will also be important to determine whether the effects of the diet on cholesterol are the same during weight maintenance as they are they are during weight loss."
Results of this first randomized, controlled study of the Atkins Diet suggest that low-carbohydrate diets may not be as harmful as anticipated.
"Larger and longer studies are needed to assess the long-term safety and efficacy of low-carbohydrate approaches in the management of obesity," Foster said. "These preliminary data suggest that weight losses will be comparable to conventional approaches over a one-year period, but there may be some favorable effects of a low-carbohydrate approach in terms of triglycerides and HDL (good) cholesterol."
This study was funded through grants from the National Institutes of Health. Others who participated in the study at Penn were Brian McGuckin, EdM, research coordinator; Philippe Szapary, MD, assistant professor of medicine; and Daniel Rader, MD, associate professor of medicine.
Similar findings for a low-carbohydrate diet by another group of Penn faculty working at Philadelphia VA Medical Center were also reported in the May 22 issue of the New England Journal of Medicine. In this six-month study, Frederick Samaha, MD, and colleagues found that a low-carbohydrate diet was associated with greater weight losses, reductions in triglycerides and improvements in insulin sensitivity compared to low-calorie, high-carbohydrate diet in 132 patients who were an average 53 years old and 288 pounds.
Foster and his colleagues at Washington University and the University of Colorado are currently enrolling participants for a large, NIH-funded, five-year study of low- and high-carbohydrate diets.
"This larger study of 360 participants will help us more fully assess the benefits and risks of low-carbohydrate diets on bone mass, kidney function, arterial function and exercise tolerance," Foster said.
Source: UPHS News
Contact: UPHS Department of Public Affairs at 215-662-2560.