Many experts believe that the potential benefits and risks of popular diets have not been adequately studied. Four popular diet plans including Atkins (a very low-carb, high-fat diet), Zone (a low-carb diet), LEARN (a low-fat, high-carb diet based on U.S. guidelines) and Ornish (a very high-carb diet) were recently compared. The study found that overweight and obese women on the Atkins diet lost the most weight.
The randomized study, published in the Journal of the American Medical Association, investigated the effects of four popular weight loss diets on weight loss. Researchers at Stanford University in California administered either the Atkins, Zone, LEARN or Ornish diets to 311 premenopausal overweight and obese women. The participants attended weekly diet classes for two months. The participants then followed the diets on their own for the following 10 months. The researchers obtained body composition measurements and blood samples from the participants.
The researchers found that the Atkins group had an average weight loss of 10.4 pounds, the LEARN group lost 5.7 pounds, the Ornish group lost 4.85 pounds, and the Zone group lost 3.5 pounds. Findings also revealed that all four groups had improved blood pressure, cholesterol levels and insulin sensitivity, although the Atkins group had increased LDL (bad) cholesterol. However, critics of the study claim that the participants were not strictly following their assigned diet plans.
"In this study, premenopausal overweight and obese women assigned to follow the Atkins diet, which had the lowest carbohydrate intake, lost more weight and experienced more favorable overall metabolic effects at 12 months than women assigned to follow the Zone, Ornish, or LEARN diets," the study authors write. "While questions remain about long-term effects and mechanisms, a low-carbohydrate, high-protein, high-fat diet may be considered a feasible alternative recommendation for weight loss."
REFERENCES:
1. Gardner CD et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA 2007 Mar 7;297(9):969-77.
Posted by Elaine Gavalas on March 27, 2007 02:35 PM
