Monday October 30, 10:01 am Eastern Time
Press Release
SOURCE: North American Association for the Study of Obesity
New Research Examines Effectiveness and Weight Loss Maintenance Of the Low Carbohydrate Diet
Studies Suggest a Contrast Between Scientific Findings and Dieter's Actions
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.

For more information on the NAASO 2000 Annual Meeting, visit http://www.naaso.org .

SOURCE: North American Association for the Study of Obesity

Hi Wa'il and all,

Very interesting report; I noticed though that there was no evidence presented as to why many following a lowcarb regimen did not maintain the weight loss. Did they regain the weight even though they were still lowcarbing (doubtful) or did they regain after returning to a high carb/high fat WOE??? Some people do give in to cravings and/or the popular hype.

I went back through the archives of NAASO; from July '99, a study they published re "Predictions of Weight Loss Maintenance" (Passman and Westenterp-Plantenga) showed a variability of over 50% in weight gain following a reduced-energy (read calorie) regimen, INCLUDING lowcarb. The following were the priority factors, and had NOTHING to do with low carb VS high carb/low fat. The greatest factors for predicting lack of success at maintaining weight loss, were #1) frequency of previous dieting attempts, ie, chronic yo-yo dieters were least successful, also earlier age of beginning the diet-then-gain-cycle. #2) family history of obesity. #3) change in BMR, ie lowered metabolic rate due to chronic dieting or other health factors. #3) personal hunger score, ie, did the diet not provide satiety for the client?

A good study, but still inconclusive, I think.

from Doreen

Nice research Doreen!

What I didn't believe in this is that low-carb diets are lower in calories. However, the study was not the usual anti low-carb propaganda.

Wa'il

This article is really interesting, partly, I think, for what it leaves out.

So what if only 25 subjects out of 3000 maintained a weight loss on a low-carb diet? That figure is only meaningful if we know the percentage of low-carb dieters at the _beginning_ of the study. If only, say 1% of the study participants consumed a low-carb diet to begin with, even if not one of them gains back a pound, there will still only be 1% of low-carbers at the end of the study! It's obvious!

To accurately compare the low-fat and low-carb diets, we would need to do a controlled experiment, with 50% of subjects randomly assigned to the low-fat diet, and 50% randomly assigned to the low-carb diet. Diets and weight would have to be monitored over a period of, say, a year. Only then could you even begin to hypothesize about the causal effects of diet.

I haven't read the original study, but it sounds screwed to me.

As to eating fewer calories on a low-carb diet: I keep track of calories on and off, and it's true, I do eat a lot less on a low-carb diet. But so what? What I'm _not_ eating is the stuff that everyone knows is bad for me - sugar, white rice, etc, etc, etc. I don't even _want_ to eat it. Somehow I don't see why that's a problem, or a valid critique of the low-carb diet. Frankly, I don't care why this WOE works - metabolic changes, fewer calories, or the tooth fairy waving a magic wand over me in my sleep - as long as it works!

And notice how they slipped the decrease in cholesterol figures in there? Why isn't this being trumpeted in the headline?

OK, end of lecture!

Rachel

The trouble with these published reports is that most of the lay public don't bother to read the meat of the studies, they just read the headlines (kinda like how I read the newspaper :-) Once again, it all comes down to size - whichever headline is BIGGER and LOUDER, is the one that gets noticed. It would be interesting to see just who provided the funds to back the study, though.

Doreen