Diet study: Hold the carbs, not the fats
By Neil Munshi, Globe Correspondent
Low-carbohydrate and so-called Mediterranean diets may be more effective than low-fat diets, according to a major new study published in tomorrow’s New England Journal of Medicine.
Researchers studied 322 moderately obese employees of a research center in Israel, randomly assigning them to three diet groups, and providing them with encouragement and instruction over a two-year period.
Members of the low-fat group lost an average of 6.4 pounds, while those in the low-carb and Mediterranean groups lost about 10, said Dr. Meir Stampfer, associate director of the Channing Laboratory at Brigham and Women's Hospital, and the paper's senior author.
While there has been concern that low-carb diets can be harmful to cardiovascular health, Stampfer said that the participants who followed the low-carb and Mediterranean diets actually had better cardiovascular health than those in the low-fat group. (The study was funded in part by the Dr. Robert C. and Veronica Atkins Foundation, which supports independent scientific research. The late-Robert Atkins was known for promoting a low-carbohydrate diet.)
For people with cholesterol problems, the low-carb diet seemed best; for those at risk for diabetes, the Mediterranean diet provided more health benefits.
"The take-home message should be that we should abandon the idea that low fat diets are the number one way for people to lose weight –- it wasn’t the best diet, it can be helpful for some people, but overall I think the first choice should be the Mediterranean or the low carb," he said.
Study participants generally ate lunch at the same cafeteria, where foods were color-coded with stickers to correspond to the different diets; they also met with dietitians periodically throughout the two years. People in the low-fat group were advised to eat low-fat grains, vegetables, fruits, and legumes, and were told to avoid sweets. In the low-carb group, participants were advised to choose vegetarian sources of fat and protein, and to limit carbohydrate intake. And those on the Mediterranean regimen were advised to eat a diet high in fish and poultry, as well as olive oil and nuts.
Participants, 86 percent of whom were men, were encouraged to continue the eating patterns at home. Calories were not limited in the low-carb group, but in the other groups, women were expected to eat 1,500 calories a day and men, 1,800.
One of the study’s great strengths, Stampfer said, was that after one year, 95 percent of participants were still following the diet, and 85 percent stayed on after 2 years. Most people have trouble sticking with regimens for that long.
This suggests that diets connected to the workplace may be particularly effective, according to Susan Roberts, a Tufts University nutrition professor.
“Whether Americans would want this is another story of course," she said in an e-mail. "It seems fairly invasive to have overweight people in your company selected out for dietary instruction and monthly weigh-ins.”
Business groups agree that workplace diets pose ethical problems.
“We would never ever say we’re putting our employees on a diet," said LuAnn Heinen, vice president of the non-profit National Business Group on Health. "But companies have really connected the dots -- we’re paying for healthcare costs, our employees are paying for healthcare costs and we’re serving them Krispy Kremes every morning.”
Instead of diets, she said, businesses are now taking steps to write caloric limits or nutritional guidelines into their contracts with food service providers.
Still, Stampfer said he would like to see businesses apply the study's findings. “It’d be nice if employers institute this kind of thing more broadly,” he said. “It’s really in the employer’s interest in having healthy employees and a modest investment in nutrition and support would benefit everyone.”
Roberts, of Tufts, said it's not clear from the research whether an individual, dieting without the workplace support provided by the study, would have the same weight-loss success.
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Could you fill in some details? How low was low for each of these diets? For the low-fat, what percentage calories from fat? For the low-carb, what percentage calories from carbohydrates? What sorts of carbohydrates were involved in each (simple sugars vs. complex carbohydrates)? Without this sort of information, this article is not terribly useful. What I consider "low-fat" and what the American Cancer Society considers "low-fat", for instance, are very different from one another.
I have been following a very low carb diet for 3 months and have lost about 26lbs. I find it to be easier than anything else that I have tried. I have not watched caloric intake at all. After the first two weeks, I found that I really didn't miss the carbs very much. I feel I have more energy than ever. I eat mostly eggs, cheese, nuts, mostly lean meats, low carb vegetables and fruits. I do take a multivitamin and a calcium supplement. I used to have a lot of difficulty with heatburn and stomach irritability, but I rarely do now. I even feel less moody. I can definitely see myself sticking to a low carb way of eating.
new thinking.....i agree....based on my experience
The following quotes are from an interview with Walter Willett, chair of the department of nutrition at Harvard School of Public Health.
This study is questionable due to the small sample size, the funding of Atkins, and most importantly the following quotes from an recent interview with Walter Willett, chair of the department of nutrition at Harvard School of Public Health:
"From many kinds of studies conducted over years, we are quite confident now that a calorie from fat will cause a similar amount of weight gain as a calorie from carbohydrate. There are some interesting questions about whether eating carbohydrate calories versus fat calories will make you eat more calories, but based on what you put into your mouth, it's pretty clear that the source of the calories is really not important."
Additionally, from an recent interview with Walter Willett, chair of the department of nutrition at Harvard School of Public Health:
"The best way to get to the bottom line is to look at long-term studies where we randomize people to a high-fat/low-carb diet or to a low-fat/high-carb diet and follow them for at least a year or more. That kind of study takes into account the possibility that one kind of diet provides more satiety; so, over the long run you would see more weight loss on that diet. But those studies - half a dozen or more such studies have been done - show quite clearly that the percentage of calories from fat has very little effect on long-term weight loss."
If companies stop serving 'junk food' then I would bet that 2/3 of the people who used to eat so-called "empty calories" on the job would stop. The ready availability of the high-sweet and fat content items is part of the problem.
Obesity per se is not the problem. The real issue is the health and mortality consequences which follow from obesity. In November Harvard Medical School studied obese mice. The team of researchers gave one group biotivia transmax resveratrol extract, a commercial version of a compound found in red wine, and the other a placebo. The group receiving transmax resveratrol lived 31% longer and did not contract the normal diseases of aging such as diabetes, tumors, and cardiac diseases. Their endurance and energy levels also improved dramatically. Resveratrol is clearly no substitute for a good diet, exercise and a healthy lifestyle but it may augment all of these and extend the potential for ultimate life span. We need to first concentrate of the prevention of the disease of obesity and treat the excess weight as a separate issue. This approach will result in a reduction of suffering and huge health care cost savings.
The only surprise for me in this article is that it has taken so long for some people to wake up to the myth of the low fat approach to losing weight.. I've been a holistic nutritionist for 10 years and people in my field have known this for at least 8 of those 10 years. The fact is, there was never any scientific evidence for the low fat approach to weight loss
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