It's Not What You Eat, It's How Much

Feb. 26, 2009— -- Dieters everywhere -- yo-yo dieters, crash dieters, fad dieters, dejected and jaded dieters -- may take heart.

A new study offers a flexible take on what it means to diet while underscoring fundamental rules about weight loss.

The study, published in the New England Journal of Medicine, suggests the type of weight-loss diet doesn't matter as much as sticking to it.

Researchers compared a low-fat, average protein diet, a low-fat, high-protein diet, a high-fat, average-protein diet, and a high-fat, high-protein diet in 811 middle-aged obese people over two years. Each group lost an average of 13 pounds after one year, though slowly started to gain it back in the second year, bringing the average lost after two years to nine pounds.

"In the end, all the diets produced weight loss to the same extent," said Dr. Frank Sacks, lead author of the study and professor in the department of nutrition at the Harvard School of Public Health. "It really doesn't matter what particular amounts of fat, carbohydrates or proteins you eat."

The diets for each group were calibrated to the calories necessary for each participant to reach their ideal body-mass index -- which meant restricting calories overall.

"There really wasn't magic revealed in the specific composition of the diet," said Dr. Howard Eisenson, executive director of the Duke Diet and Fitness Center. "I thought their conclusions made sense and jibed with what many of us in the field have long been thinking."

In addition to weight loss, subjects reduced their risk of heart disease and diabetes and improved their blood pressure.

The researchers used daily food reports, as well as one-on-one and group sessions with a dietician, to keep participants on track.

"All of that created a kind of synergy for keeping you motivated and informed," said Rudy Termini, 69, one of the study participants who ate a high-fat, moderate-protein diet totaling 1,800 calories each day.