Secret to Losing Weight: Eat Less Food

It's bad news for the diet book business, because the best way to lose weight apparently comes down to three words: "eat less food." The long version, admittedly, is "eat less food and make sure the food you eat has few calories."  Still, it's a very short book.
The New England Journal of Medicine writes up a study led by Harvard School of Public Health professor Frank Sacks, who assigned 811 overweight people to one of four diets with different percentages of fat, protein and carbohydrates, and tracked their weight for two years. All of the diets reduced the participants calorie intake by about 750 calories a day, and no diet provided fewer than 1,200 calories a day. Sacks found that after six months, every diet group had lost about the same amount of weight–13 pounds, and after two years every diet group had regained the same amount of weight, for an average weight loss of 9 pounds. The big take away, so to speak, is that people lose weight if they lower calories, no matter how they do it.
Read more about it in US News & World Report, or the New York Times. Read an abstract from the study in the New England Journal of Medicine.