NEW YORK (Reuters Health) - Obese women who follow low-carbohydrate diets, such as the Atkins diet, may lose more weight in a four-month period than those who go on low-fat diets, new study findings show. The reason for the greater weight loss, however, is not clear.

"The differential weight loss is not explained by differences in resting energy expenditure, thermic effect of food or physical activity," write study author Dr. Bonnie J. Brehm, of the University of Cincinnati, Ohio and her team.

In a previously published study, Brehm and her colleagues compared the effects of a low-carbohydrate diet versus a low-fat diet among obese women. They found that the women on the low-carbohydrate diet lost more than twice as much weight as those in the comparison group during a six-month study period.

The researchers hypothesized that the greater weight loss among those on the low-carbohydrate diet was due to the women's greater energy expenditure. "If it's not calories in, it must be calories out," Brehm told Reuters Health.

Some advocates of low-carbohydrate diets say that such diets promote increased energy expenditure, but this claim has not been formally tested, until now.

To investigate, Brehm and her team randomly assigned 50 moderately obese women to a low-carbohydrate diet group or a low-fat diet group. Only the low-fat group was told to restrict their caloric intake. Forty women completed the study.

By the end of the four-month study, women in both groups had lost weight and body fat, the researchers report in this month's issue of the Journal of Clinical Endocrinology and Metabolism. However, the low-carbohydrate group lost more than 10 percent of their body weight, while the low-fat group lost about 7 percent.

Specifically, the low-carbohydrate group lost 9.8 kilograms (21.6 pounds) of weight and 6.2 kilograms (13.7 pounds) of body fat, while the low-fat group lost about 6.1 kilograms (13 pounds) of weight and 3.2 kilograms (7 pounds) of body fat, the report indicates.

To estimate their level of physical activity, women in both groups were fitted with pedometers, which recorded the number of steps they took daily. At the start of the study, both groups of women had similar pedometer readings, and by the end of the study, there were no significant changes, according to Brehm and her team.

Resting energy expenditure was also similar between the two groups at the start of the study and remained comparable four months later.

The thermic effect of food (TEF), which comprises up to 10 percent of the amount of energy consumed daily, includes the energy expended during digestion. When the investigators obtained TEF measurements after the women ate breakfasts containing a similar number of calories, they found that those on the low-fat diet expended more energy in a five-hour period.

This suggests that the low-fat meal was absorbed more quickly than the low-carbohydrate meal, the report indicates. Yet, even if the TEF of the low-carbohydrate meal had been underestimated, the researchers "would not have approached the amount of energy needed to account for the greater weight loss in this group," they write.

"These results confirm that short-term weight loss is greater in obese women on a low-carbohydrate diet than in those on a low-fat diet even when reported food intake is similar," according to Brehm and her team.

SOURCE: Journal of Clinical Endocrinology and Metabolism, March 2005

© Reuters 2005. All Rights Reserved.
http://www.reuters.com/newsArticle....storyID=7964727

This is great news!
I, myself, am following a relatively high-fat, low-carb diet, but it's the so-called "good fats", unsaturated, from almonds, fish, olive oil, etc.

I do this because I am worried about the effect of saturated fats on my cholesterol.

Which raises the question - what results have you had with your cholesterol - better - worse since going on Atkins? Have you read any research on this?

I would love to hear what you have to say because, frankly, I would love to eat a steak without worrying that my arteries will clog up from it!

I forgot to add - atherosclerosis (hardening of the arteries which is due to cholesterol buildup) runs in my family

I keep saturated fat at about 10%. My perspective is that the jury is still out on this one. My cholesterol improved on Atkins, but I started a statin recently because while my levels are fine for most folks, as a diabetic, they just were not good enough.

This kind of report is crucial to breaking the low-fat logjam among researchers, however the tradition is so established (calorie theory has been unchallenged for over a century?) that scientists won't take note until they see perhaps 30 or 50 or 100 separate studies saying the same thing. Then they might concede that possible calorie theory is questionable...We just have to keep banging their heads against it.

I've seen this in several different studies. Most are done over a year's time and the results say that weight loss is equal between low carb and low fat diets over that time frame. People lose weight faster on the low carb but also quit it quicker than low fat so after a year total weight loss is the same. One of the problems with low carb diets is how quickly the weight comes back if you go back to the old habits.

Which means, of course, it's time for someone--okay, sure, I'll do it--to chime in and say in a flurry of italics, acronyms, punctuation, cliches, and caps: this is why it has to be a change of lifestyle, a WOLF, not just a diet.

As I have learned to my chagrin and great cost, not once, but twice.

I'm slow, but eventually I catch on-- I'm running out of time for being stupid. Thin is not cured.
If I want different results, I need to do something different.
I can't eat white sugar and flour, fried in grease.

And it is hitting me for the first time, maybe that doesn't make me wierd. Maybe the great American junk food diet is the wierd thing. Maybe, just maybe, I'm normal, and my bod is revolting by storing the toxic stuff I eat as fat.

Two words for the cholesterol-heart disease theory: it's bunk. Every major study purporting to show a causal link was severely methodologically flawed or the results "creatively" interpreted. Read Uffe Rasknov's book "The Cholesterol Myths," and you will shake your head in disbelief at the unsound basis of this theory.

The cholesterol found clogging people's arteries during autopsy is a result of the body's trying to bandage blood vessels injured by inflammation. In fact, cholesterol-lowering drugs work not because of their direct effect on cholesterol, but because they reduce inflammation. If you check the fine print on the ads, you can see verbiage that hedges the benefits of reducing cholesterol.

Leading cardiac researchers are now abandoning this theory, though very quietly, so as to save face. Malcolm Kendrick, M.D., recently attended a European conference on cardiac health, and in the keynote speech, the slide showing the leading causes of cardiac mortality omitted cholesterol. I'll post this article on my web site, Nutrition Recovery (www.majicom.com/nr), tonight, with the title "Do researchers believe the cholesterol-heart disease theory?"

My C-Reactive Protein (a measure of inflammation) actually went up substantially over my first six months on LC, even though my cholesterol went down. In a week I'll be tested to see if the statin is lowering it, as well as having my repeat lipid panel.

These are social studies masquerading as scientific ones. When or whether someome "goes back to their old eating habits" has nothing whatever to do with whether a diet medically works. Dropping off the diet is a completely separate SOCIAL issue. So why are they selling a social study as some kind of physical proof of failure? This is an intentional diversionary tactic to confuse a lot of average people.

These studies say, in effect, "there's no physical benefit to dieting because people are weak-willed creatures of habit." This is the most condescending attitude imaginable, as well as completely scientifically irrational. The cigarette makers tried to pull this fast one, too, but it was just too obvious to work (so now they've moved their operations to the under-developed world).

The ultimate message is "Experts have decided you are mentally incompetent to make choices to improve your own health, so we will make all nutritional decisions for you." It's not even clever manipulation, but more like hypnotism. "Go back to sleep or you'll be in grave danger!", and "Don't listen to scientific evidence because EVERYONE KNOWS the Earth is flat, what stronger proof is there than that?" Pay no attention to the man behind the curtain, indeed.

Successful low-carbers dont quit this diet. People who quit do so because they are ridiculed by their doctors, coworkers and "friends". Or they are doing it out of trendy-ness and don't really understand it to begin with. One of the saddest things I've noticed is how willfully ignorant the general public is about this issue. Well, its their funeral.

As for last year's marketing "craze", it was mercenary, mis-guided and over-priced, and we are better off without it. Marketers mistakenly decided it was a "specialty" item which we would pay exhorbitantly for. Half the carbs-coke for twice the price? Wrong on both counts. Then they took our rejection of their bad salesmanship as rejection of low-carbing. We don't need alot of special "processed" products anyway, low-carbing can be considered part of the "whole foods" movement. Though some reduced-carb products are very helpful, like bread and pasta, and I would buy their other products for reasonable prices. (Favorite product - Hood low-carb milk 1%, 2%, whole and CHOCOLATE -2% fat / 2 grams sugar per cup - best kept secret! A guilt-free, side-effect free, large quantity indulgence.)

(Taming, its good that you post your particular info. We don't want to be guilty of reverse brainwashing and ignorance. Individual cases can be unique, respond differently, and have very different causes unrelated to diet. Even about LC, there are many new questions we can't answer yet. But that's the way it should be if we're facing the questions honestly instead of hiding evidence we don't want others to see.)