The NIH-funded Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial, published in The Annals of Internal Medicine reports on an unusually large and diverse study of the impact of low-carb eating and finds huge benefits relative to low-fat diets.
Both groups were told to eat a normal calorie load, one group avoided carbs while the other avoided fat. The low-fat group lost muscle mass, while the low-carb group enjoyed an average of 8lbs greater weight-loss, higher muscle-gain, and better cholesterol levels.
By the end of the yearlong trial, people in the low-carbohydrate group had lost about eight pounds more on average than those in the low-fat group. They had significantly greater reductions in body fat than the low-fat group, and improvements in lean muscle mass — even though neither group changed their levels of physical activity.
While the low-fat group did lose weight, they appeared to lose more muscle than fat.
“They actually lost lean muscle mass, which is a bad thing,” Dr. Mozaffarian said. “Your balance of lean mass versus fat mass is much more important than weight. And that’s a very important finding that shows why the low-carb, high-fat group did so metabolically well.”
The high-fat group followed something of a modified Atkins diet. They were told to eat mostly protein and fat, and to choose foods with primarily unsaturated fats, like fish, olive oil and nuts. But they were allowed to eat foods higher in saturated fat as well, including cheese and red meat.
A Call for a Low-Carb Diet (Anahad O'Connor/NYT)
(via Hacker News)