Previously, the ADA did not recommend low-carbohydrate diets because of a lack of sufficient scientific evidence.

"The Standards of Medical Care in Diabetes -- 2008" found evidence that the most important determinant of weight loss is not the composition of the diet, but whether the person can stick with it.

"The risks of overweight and obesity are well known. We recognize that people are looking for realistic ways to lose weight," the ADA's Ann Albright said in a statement. "The evidence is clear that both low-carbohydrate and low-fat calorie restricted diets result in similar weight loss at one year. We're not endorsing either of these weight-loss plans over any other method of losing weight. What we want healthcare providers to know is that it's important for patients to choose a plan that works for them."

People following low-carbohydrate diets should be monitored for blood fats, cholesterol and triglycerides, while those on high-protein diets with kidney disease should be counseled about appropriate intake of protein and their kidney function should be monitored, the annual clinical practice recommendations said.