New Research Examines Effectiveness and Weight Loss Maintenance Of the Low Carbohydrate Diet
LONG BEACH, Calif.,
Oct. 30 /PRNewswire
Clinical studies presented today at the annual meeting of the North American Association for the Study of Obesity (NAASO), show that most obese people who are able to achieve successful long-term weight loss eat a low-fat, high carbohydrate diet. However, a low-carbohydrate, high-protein/fat diet can also help people lose weight.
"Obese people are bombarded with conflicting approaches to losing weight," said George Blackburn, M.D., Ph.D., immediate past president of NAASO, associate professor of surgery and associate director of the Division of Nutrition at Harvard Medical School/Beth Israel Deaconess Hospital, Boston, Mass. "These three studies show that marked differences in diet composition will lead to weight loss as long as less calories are consumed than are expended by the body."
A group of investigators at the University of Colorado Health Sciences Center, Denver, Colo. and Brown University, Providence, R.I. established the National Weight Control Registry (NWCR), a group of approximately 3,000 individuals who have maintained a weight loss of 30 pounds or more for at least one year. Data from this registry found that only 204 of 2,681 NWCR subjects reported eating less than 90 grams of carbohydrates a day. Of those only 25 subjects reported eating a diet that was less than 24 percent carbohydrate.
"What we found was that most people who achieved long-term weight loss success did so by consuming a low-fat, high-carbohydrate diet," said Holly Wyatt, M.D., assistant professor of Medicine, University of Colorado. "Very few successful weight loss maintainers ate a low-carbohydrate, high-protein/fat diet."
A prospective study, funded in part by the Atkins Center for Complementary Medicine, was conducted to evaluate the effect of a low carbohydrate, high-protein/fat diet in achieving short-term weight loss. Researchers at the Center for Health Services Research in Primary Care, Durham, N.C. reported data from a six-month study that included 51 individuals who were overweight, but otherwise healthy. The subjects received nutritional supplements and attended bi-weekly group meetings, where they received dietary counseling on consuming a low-carbohydrate, high-protein/fat diet. After six months, subjects experienced an average weight loss of 10.3 percent and an average decrease in total cholesterol of 10.5 mg/dl.
Twenty patients chose to continue the diet after the first six months, and after 12 months, their mean weight loss was 10.9 percent and their total cholesterol decreased by 14.1 mg/dl.
"This study of overweight individuals showed that a low carbohydrate, high-protein/fat diet can lead to significant weight loss at one year of treatment," William S. Yancy, M.D., fellow, Health Services Research, Center for Health Services Research in Primary Care, Durham, N.C.
The reason for losing weight by eating a low-carbohydrate, high-protein/fat diet was explained by the results from another clinical study, supported by a grant from The E. Donnall Thomas Resident Research Program. In this prospective study, 18 overweight and obese adults, including nine males and nine females, were instructed to follow the low-carbohydrate, high-protein/fat diet. Dietary intake was evaluated before and two weeks after starting the diet. On average, subjects consumed 1000 kcal less per day two weeks after than before starting the diet. The reduction in calories correlated highly with each subject's weight loss.
"Our study demonstrates that low carbohydrate diets can cause a decrease in total calorie intake. Therefore, obese persons who lose weight by consuming this type of diet, do so by consuming less calories, not by altering body metabolism that allows weight loss despite high calorie intake," said Bernard V. Miller III, M.D., the lead investigator of this study from The Research Institute and Clinical Pharmacology Research Center in Cooperstown, N.Y.
"The results from these studies underscore the need for additional research to directly compare the effectiveness and safety of a low-carbohydrate, high-protein/fat diet approach with the traditional high-carbohydrate, low-fat diet," said Dr. Blackburn.
The North American Association for the Study of Obesity (NAASO) is a leading scientific society dedicated to obesity. NAASO is committed to encouraging research on the causes and treatment of obesity, and to keeping the scientific community and public informed of new advances, as it becomes more widely recognized as a disease and public health threat.