Low carb diet more effective for weight loss
People who followed a low carbohydrate, high-protein diet lost more weight than people on a low fat, low-cholesterol, low-calorie diet during a six-month comparison study at Duke University Medical
Center. However, the researchers caution that people with medical conditions such as diabetes and high blood pressure should not start any diet without close medical supervision.
"We found that the low carb diet was more effective for weight loss," says lead researcher Will Yancy, MD, an assistant professor of medicine at Duke University Medical Center and a research
associate at the Veterans Affairs Medical Center in Durham, North Carolina. "The weight loss surprised me, to be honest with you. We also found cholesterol levels seemed to improve more on a low
carb diet compared to a low fat diet."
Low carb diet burns body fat
The study is the first randomized, controlled trial of an Atkins-style diet approach, which includes vitamin and nutritional supplements. Along with losing an average of 26 pounds, dieters assigned
to the low carbohydrate plan lost more body fat, and lowered their triglyceride levels and raised their HDL, or good cholesterol, more than the low fat dieters. The low fat dieters lost an average of
14 pounds. Though the low fat diet group lowered their total cholesterol more than the low carb dieters, the latter group nearly halved their triglycerides and their HDL jumped five points.
The low carbohydrate group reported more adverse physical effects, such as constipation and headaches, but fewer people dropped out of the low carbohydrate diet than the low fat diet.
The low carb weight loss plan
The results appear in the May 18, 2004 issue of the Annals of Internal Medicine
. The research was funded by an unrestricted grant from the Robert C. Atkins Foundation. The study authors have no financial interest in Atkins Nutritionals Inc.
The low carbohydrate group was permitted daily unlimited amounts of animal foods (meat, fowl, fish and shellfish); unlimited eggs; 4 ounces of hard cheese; two cups of salad vegetables such as
lettuce, spinach or celery; and one cup of low carbohydrate vegetables such as broccoli, cauliflower or squash. They also received daily nutritional supplements recommended by Atkins -- a
multivitamin, essential oils, a diet formulation and chromium picolinate. There were no restrictions on total calories, but carbohydrates were kept below 20 grams per day at the start of the diet.
The low fat, low-cholesterol, low-calorie group followed a diet consisting of less than 30 percent of daily caloric intake from fat; less than 10 percent of calories from saturated fat; and less
than 300 milligrams of cholesterol daily. They were also advised to cut back on calories. The recommended daily calorie level was 500 to 1,000 calories less than the participant's maintenance diet
-- the calories needed to maintain current weight.
Study participants were encouraged to exercise 30 minutes at least three times per week, but no formal exercise program was provided. Both sets of dieters had group meetings at an outpatient
research clinic regularly for six months.
The study builds on earlier results by the Duke University Medical Center researchers showing a low carbohydrate diet can lead to weight loss -- the first study of the low carbohydrate diet since
1980. Dr Yancy and co-investigator Eric Westman, MD, are currently testing whether a low carbohydrate diet can help diabetics control their blood sugar levels.