What constitutes a healthy diet has been more a matter of opinion than of science because there have been few good studies to settle the issue. But in July researchers published a paper in the New England Journal of Medicine that describes a well-designed, randomized, controlled study of human nutrition—with surprising results. They tested three diets: a low-fat diet; the high-fat, low-carbohydrate regimen commonly called the Atkins diet; and the Mediterranean diet, which includes lots of olive oil, grains, fruits, nuts, and fish, and little meat or dairy products.
The scientists found that both the Mediterranean and the low-carbohydrate diets are better for weight loss than a low-fat regimen and have other beneficial effects as well.
The two-year study, partially funded by the Atkins Foundation, included 322 overweight but otherwise healthy men and women. One-third of the participants followed each diet, under the guidance of dietitians who periodically interviewed and counseled them. The lab staff and study coordinators were unaware of which subjects were on which diet.
All three plans produced weight loss, but the low-carb and Mediterranean groups lost more. Low-carb had the greatest increase in HDL, the so-called good cholesterol. C-reactive protein levels, a risk factor for heart disease and other illnesses, decreased in both the low-carb and Mediterranean, but not in the low-fat. In short, the researchers found that both the Mediterranean and low-carb diets are effective alternatives to the low-fat regime for weight loss and are just as safe.
Meir Stampfer, a coauthor of the study and professor of epidemiology at Harvard University, says, “If your low-carb is a cheeseburger without the bun, that’s a bad choice. If it’s fish, olive oil, and other plant-based oils, that’s a fine choice.”