Eight years after the Atkins version of the low-carb diet hit the media, researchers are finding some results that surprise them. As a low-carber for the last eight years myself, I could not be more pleased. I love to see the new research replacing old assumptions.
A federally funded two year study led by Gary Foster, Ph.D., director of Temple University's Center for Obesity Research and Education is the largest study thus far of its kind. Research was done at three major medical centers in Denver, Philadelphia and St. Louis. The report was published in Annals of Internal Medicine.
The purpose of this multicenter clinical trial was first and foremost to look at weight loss. It also looked at such secondary issues as bone mineral density, cardiovascular risk factors
The two groups were made up of 307 adults, between 60 and 70 percent of them women, and about 70 percent of them white. Approximately 25 percent were obese but without diabetes or cholesterol problems.
The average age of participants was 45. The average body mass index was 36. Average weight was 227 lbs.
There was some attrition as a number of participants in the study dropped out during the two year period. About 58 percent of the low-carbers and 68 percent of the low-fat dieters stayed with it all the way through however.
One group ate a low-carb diet similar to the Atkins diet with carbohydrates being limited to 20 grams a day for the first 12 weeks. Carb intake increased by 5 grams a day each week.
There was no limit placed on amounts of fat and protein that this group could eat.
The other group ate a low-fat low-calorie diet restricted to 1200 - 1500 calories a day for the women and 1500 - 1800 calories a day for the men.
Carbohydrates made up 55 percent of their calories, fat was 30 percent and protein was 15 percent.
All participants in both groups attended sessions aimed at improving eating habits, becoming more physically active and support to stay with their diets.
In the first six months, the low-fat diet brought better reduction of LDL ("bad") cholesterol but this difference levelled off and there was no difference by the end of the study.
Periodic monitoring for any changes in bone density, body fat percentages and blood pressure showed results were the same for both groups.
Each group lost about 24 pounds (about 11 percent of body weight) by the end of the first year. They had lost and kept off about 15 pounds (about 7 percent of body weight) by the end.
Researchers found that those on the low-carb diet had a rapid decrease in triglycerides and VLDL cholesterol. Having high VLDL levels indicate greater risk of coronary artery disease. This can lead to heart attack or stroke.
This difference between the two groups showed up after the first three months. By 24 months the groups were the same again but overall, the low-carbers fared better with VLDL cholesterol levels.
"For many years there have been concerns that the low-carbohydrate approach to weight loss was bad for the heart," Foster said. "This study would suggest those concerns are largely unfounded."
The low-carb dieters had slightly better reductions in total cholesterol than the low-fat dieters. HDL ("good") cholesterol increased by 23 percent for low-carb as opposed to 12 percent for low-fat. The low-carb group performed better here consistently through the study.
Foster said that this increase of HDL as seen with the low-carb diet is the kind you'd get from medicines for HDL.
"For a diet, that's pretty impressive," Foster said. "There have been concerns for years that a low-carb diet could have a number of ill effects on the body, but I think what this shows is that some of those concerns are unfounded."
Eric Westman is an internist and director of the Duke Lifestyle Medicine Clinic in Durham, North Carolina. He is also a co-author of "The New Atkins for a New You".
Westman said, "It's great to see the science confirm what we see clinically." He has done studies on low-carb dieting, and uses it in his practice. "We see people losing 50 to 70 pounds a year."
Resources:
Similar Weight Loss with Low-Carb, Low-Fat Diets
http://www.medpagetoday.com/PrimaryCare/Obesity/21490
Low-carb, low-calorie diets can both result in weight loss
http://www.usatoday.com/news/health/weightloss/2010-08-03-battleofthediets03_ST_N.htm?csp
Low-carb diet beats low-fat on 'good' cholesterol
http://www.msnbc.msn.com/id/38528158/ns/health-diet_and_nutrition
Low-fat, or low-carb? That is the question
http://pagingdrgupta.blogs.cnn.com/2010/08/02/low-fat-or-low-carb-that-is-the-question/?utm_source
Low-Carb Diets Improve Cholesterol Long Term
http://www.webmd.com/cholesterol-management/news/20100802/low-carb-diets-improve-cholesterol-long-term
What is VLDL cholesterol? Can it be harmful?
http://www.mayoclinic.com/health/vldl-cholesterol/AN01335
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