Weight Loss Vows: Low-fat diet more effective than restricting carbs

“They’ve shown that that’s bogus”, she says.

In the battle of bulges, the battle between low-carbohydrate enthusiasts against low-fat enthusiasts, this is a clear victory for the proponents of the low-fat diet. However, a new study from the US can settle the score between low fat or low carb diet for weight loss.

Any study trying to accurately answer a nutrition question has to get a little obsessive; nutrition research is notoriously hard to do well. They switched diets during the second visit.

Participants stayed in the unit 24 hours per day for two extended visits, eating the same food and doing the same activities.

During this short-term study, a low-fat diet led to the greatest overall body fat loss.

She agrees with Hall that it dispels the notion that fat loss absolutely requires a low-cab diet. Their daily calorie intake of 2700 was reduced both times by 30 percent, but from different sources (carbohydrates or fat). That didn’t surprise Hall at all. “Furthermore, we can definitively reject the claim that carbohydrate restriction is required for body-fat loss”, said the authors.

That theory focuses on the notion that carb-cutting triggers a decrease in insulin levels, while cutting fat does not.

As analyzed by the National Institutes of Health, low fat and low carb diets both contributed to weight loss, but, people appeared to have lost more when they reduced their fat intake.

How is this possible?

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“Over the long term it’s pretty close”, says Hall.

It seems like everyone is cutting carbs to try to lose weight and barely a day passes without someone touting the benefits of a carb-free life. But they didn’t find it. “It might not exist”, he says. As they were confined in the NIH laboratory, they were given the same amount of calories of low-carbohydrate and low-fat foods respectively.

It is a central dogma of the low-carb lifestyle: that while avoiding carbohydrates will force the human body into fat-burning mode, any diet that fails to suppress insulin will trap body fat in place and thwart a dieter’s hope of shifting to a leaner, healthier body type.

Dr Hall, however, cautioned against making “sweeping conclusions” about how to diet. Dr. Atkins was the one who made the principles of this diet known to people in the early 1970s and since then it has been very popular, while the low-fat diet has been increasingly criticized.

“But interestingly, study participants lost even more body fat during the fat-restricted diet, as it resulted in a greater imbalance between the fat eaten and fat burned”, he said.

More research is needed, Hall says, but “the takeaway for me is that the theory about metabolism that has previously been used to recommend low-carbohydrate diets probably doesn’t hold water”. The other group received a 30 percent cut of calories from fat while the carbohydrates and protein contents are maintained.

If metabolism doesn’t necessarily tip the scale in favor of one diet over another, what else will?

Studying the effects of diet on weight loss is often confounded by the difficulty in measuring what people actually eat-participants may not adhere to meal plans, misjudge amounts, or are not truthful in follow-up surveys.