Issue 129 Item 13 Score One For Low-Carb Diet

Atkins diet trimmed significantly more pounds and body fat in obese but otherwise healthy women than a traditional low-fat diet. According to a report released last week at the annual meeting of the American Dietetics Association, in a head-to-head comparison between two popular and distinctly different eating plans, the Atkins diet trimmed significantly more pounds and body fat in obese but otherwise healthy women than a traditional low-fat diet.

The study enrolled 53 women, aged 31 to 59, for six months. Half followed a low-fat approach, eating 30 percent of calories from fat. The other half ate according to the very-low-carbohydrate diet popularized by physician Robert Atkins.

Those in the Atkins group shed on average 18.5 pounds — about 10 of it from body fat. (The rest was due to loss of water and lean muscle.) By comparison, the low-fat group lost about nine pounds, about five of them from body fat.

Despite the results, the study’s lead author cautioned against drawing too many conclusions or abandoning a low-fat approach to weight loss. "I’m not sure that there is a take-home message from this study, except that there is more research needed," said registered dietitian Bonnie Brehm, assistant professor in the College of Nursing at the University of Cincinnati. This is one, relatively short-term study. Our conclusions are that in the short term, a low-carbohydrate diet produces loss of weight and body fat. We by no means are recommending the Atkins diet from this one study."

During the two-week induction phase of the Atkins diet, carbohydrates are limited to 20 grams a day — about the amount found in one medium apple and less than a sixth of the 130-gram daily minimum recently set by the National Academy of Sciences. Prohibited are carbohydrates rich in fiber, vitamins and minerals such as fruit, bread, grains, starchy vegetables and any dairy products other than cheese, cream or butter.

Researchers found that the women randomly assigned to follow the Atkins approach, who had an average BMI of 34, did go into ketosis, as documented by daily urine tests performed at home and by a blood test run by researchers at the three-month point of the study. Daily food records indicated that at three months, "women were taking about 41 grams of carbohydrates a day, or about 15 percent of their total calories.

By comparison, food records showed that the low-fat diet group, while consuming about the same number of calories, took in about 169 grams a day of carbohydrates. We were surprised that women could adhere to the Atkins diet as well as they did.

For the second three-month phase, both groups of women were told to adhere to their diets, but were left on their own to do so. During the second three-month phase, the low-fat group maintained their nutrient intake, while the low-carb group began to add back carbohydrates, in other words, the Atkins group found it more difficult to stay with their low-carb regimen than the low-fat dieters did with theirs.

The findings also showed that people in both groups ate the same amount of calories daily — about 1,200 to 1,500 calories a day. The groups adhered to the calorie limits equally well, but the low-fat group lost about half the weight as the those in the Atkins group.

Why Atkins participants lost more weight and body fat than women on the low-fat diet is a question that they hope to answer in a follow-up study.

Nutrition experts cautioned that these and other recent findings should not be viewed as the answer to the obesity epidemic. Still unstudied is whether long-term use of the Atkins diet may result in higher rates of illness — cardiovascular disease and kidney disease. Source: American Diabetes Association
Publication date: 2002-10-29