A study appearing today in the New England Journal of Medicine provides evidence that low-fat, low-carb, and high-protein diets all can lead to successful long-term weight loss, as long as they reduce a person’s calorie intake. While previous research has suggested that one type of diet may be better than another, the present study followed people for two years and found that lasting weight loss was similar among participants who followed diets that were similar to popular specialty weight-loss programs.

Researchers from the Harvard School of Public Health followed more than 800 overweight adults on one of four diets, each with a different distribution of nutrients: low-fat, high carb; low-fat, high-protein; high-fat, low-carb; and high-fat, high-protein. Though the diets were similar to commercial plans, the study did not directly compare popular diets. All four diets contained healthy fats, were high in whole grains, and were low in cholesterol.

Each dieter was encouraged to cut 750 calories a day from their diet, exercise 90 minutes a week, keep an online food diary, and meet regularly with diet counselors to chart their progress. After two years, the results showed that all four groups had the same average weight loss of 9 pounds and all lost an average of 2 inches off of their waistline. Most risk factors for cardiovascular disease improved for dieters as well including increases in HDL ("good") cholesterol and decreases in LDL ("bad") cholesterol, triglycerides, blood pressure, and insulin resistance.

The study also found that people who made good use of diet counseling saw better results. Those who attended the most meetings lost an average of 22 pounds, far more than the overall average of 9 pounds.

The researchers conclude that it does not matter what the nutrient composition of a diet is, as long as a diet reduces calorie-intake and remains heart healthy (high in fiber and low in saturated fats). They stress that following a restricted-calorie diet that is good for the heart allows dieters to eat a variety of foods and reduces monotony, which makes it easier for people stick with their diets. Instead of eliminating several foods from your diet, dieters just need to be reasonable about portion control. The key to successful weight loss is simply: eat less.

One researcher not involved in the study provided a different take on the results. In an accompanying editorial, she notes that after two years of very focused effort on the part of motivated participants who had access to several weight-loss resources, the average weight loss achieved was very modest. This leads her to conclude that the key to reversing the obesity epidemic may not lie in the hands of individuals. Instead, community-based programs that start in childhood and help encourage schoolchildren to eat better and move around more may be the best way to combat obesity.

Want to learn more about how to cut calories and maintain weight loss? See How can I control my weight? in the Healia Health Guide to Weight Management, or join the Healia Health Community for Weight Management.

_{Photo: davitydave, Flickr, Creative Commons}