Two randomized trials of low-fat versus low-carbohydrate weight loss diets, published in the May 18 issue of the Annals of Internal Medicine, found greater weight loss among the low-carbohydrate dieters at six months.
One study ended at six months, however, the other study continued for 12 months, and found no difference in the amount of weight lost. Both studies found a greater reduction in triglycerides and a modest difference in high-density lipoprotein (HDL, the "good cholesterol") among the low-carbohydrate dieters. High levels of triglycerides, a type of blood fat, may be linked to an increased risk of coronary heart disease.
In addition, both studies were small and had a high drop-out rate of study participants, underscoring both the difficulty in performing diet trials and of maintaining a weight loss program that is based solely on diet.
"These comparison studies again show that although weight loss may be greater on a low carbohydrate diet at 6 months, there appears to be little difference between the two diets at one-year," says Robert Bonow, M.D., past-president of the American Heart Association and chief of the Division of Cardiology at Northwestern University Feinberg School of Medicine in Chicago.
"In fact, in the six month study, 30 percent of the participants in the low carbohydrate group showed an increase in the low-density lipoprotein (LDL, "the bad cholesterol")." Robert H. Eckel, chairman of the AHA Council on Nutrition, Physical Activity and Metabolism, and Professor of Medicine at the University of Colorado Health Sciences Center, says "how an individual splits the consumption of carbohydrates, fats and proteins is not the most important issue - long-term health is."
Hundreds of published studies have shown that diets high in saturated fats have been strongly associated with an increased risk of heart disease, and diets high in fruits, vegetables, whole grains and low-fat dairy products have been associated with a lower risk of heart disease. "Individuals who are trying to lose weight should consume a dietary pattern that has abundant scientific evidence behind it.
A reduced calorie diet rich in fruits, vegetables and whole grains, restricted in saturated fat and cholesterol can help individuals lose weight and lower their risk of cardiovascular disease. It is important to get at least 30, and preferably 60 minutes of aerobic activity, such as brisk walking daily. It's the long haul that really matters," says Eckel.
For more information on heart disease and stroke, visit the American Heart Association's Web site at http://www.americanheart.org.