Weight-loss diet recommendations run the gamut from the low carbohydrate Atkins diet to the high carbohydrate Ornish diet.

It’s little wonder most people are confused when even scientists can’t seem to decide which diet is best for weight loss.

Researchers from the Stanford University School of Medicine Prevention Research Center compared the effects of four popular diets (Ornish, LEARN, Atkins, and Zone) on weight loss and heart disease risk factors in 311 overweight premenopausal women.

After 12 months, women following the Atkins diet lost the most weight (10.4 pounds), followed by the LEARN (5.7 pounds), Ornish (4.8 pounds) and Zone (3.5 pounds) diets. Caloric intake during the study was comparable in all the diets.

The Atkins group showed the greatest decreases in resting systolic blood pressure, triglycerides (blood fat) and body fat.

This is the first well-controlled, large-scale study showing that the low-carbohydrate Atkins diet caused greater weight loss at 12 months than balanced or high-carbohydrate diets, while improving several heart disease risk factors. [sources: Journal of the American Medical Association, Fitness RX]