Limiting carbs rather than fat may have a heart benefit for those who are obese
THE QUESTION Over the long run, how do the results of low-fat and low-carbohydrate weight-loss efforts compare?
THIS STUDY involved 307 adults, who averaged 45 years old and weighed an average of 227 pounds. All had body mass index (BMI) ratings in the obese range, with an average of 36 (18 to 25 is normal, 30 or more is obese). They were randomly assigned to consume a low-carbohydrate diet (with unrestricted consumption of fat and protein) or a low-fat/low-calorie diet. Everyone participated in periodic group sessions on behaviors to enhance weight loss, and all were asked to exercise (mainly walk) regularly, increasing to more than three hours a week by five months. People in both groups lost weight, but the amount lost was virtually identical: about 24 pounds, on average, after one year and 15 pounds (7 percent of their starting weight) after two years. Changes in low-density lipoprotein cholesterol and bone density did not differ between the groups after two years. However, levels of high-density lipoprotein cholesterol (the good kind) increased by more, and did so faster, for the low-carb diet group, reaching an increase of about 23 percent by the end of the study.
WHO MAY BE AFFECTED? People who are obese and want to lose weight. Millions of Americans are obese: 34 percent of adults, about 20 percent of kids 6 years and older and 10 percent of younger children. The extra weight and fat makes an obese person more likely to have heart disease, high blood pressure, Type 2 diabetes and some types of cancer.
CAVEATS People who had obesity-related diseases, such as diabetes, were excluded from the study, as were those taking cholesterol-lowering medication and people with high blood pressure; thus, the findings may not apply to them. Whether they apply to people who are overweight but not obese is unclear.
FIND THIS STUDY Aug. 3 issue of Annals of Internal Medicine.
-- Linda Searing
The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.