A low-carb diet and a Mediterranean-style diet both helped people lose more weight than a traditional low-fat diet in one of the longest and largest studies to compare the various weight-loss techniques.
The low-carb diet also improved cholesterol more than the other two, even though some critics had predicted the opposite result.
The two-year study was done in a controlled environment -- an isolated nuclear research facility in Israel, where participants received their lunch at a cafeteria (and did not have easy access to fast-food outlets). Each of the 322 participants was assigned to one of three meal plans:
1. The low-fat diet, which restricted calories and cholesterol and focused on low-fat grains, vegetables and fruits as options.
2. The Mediterranean diet, which emphasized poultry, fish, olive oil and nuts.
3. The low-carb diet, which set limits for carbohydrates and urged dieters to choose vegetarian sources of fat and protein.
Although all three approaches achieved weight loss and improved cholesterol, the Mediterranean diet, and especially the low-carb diet, had the most beneficial effects.