Low-carbohydrate diets or low-carb diets are dietary programs that restrict carbohydrate consumption primarily for weight control. Foods high in digestible carbohydrates are limited or replaced with foods containing a higher percentage of proteins and fats.

he low-carb, high-fat Atkins diet gets high marks in one of the biggest, longest head-to-head studies of popular weight-loss plans, beating the Zone, the Ornish diet and even U.S. guidelines. Even so, critics say the results show how hard it is to lose weight and keep it off.

The largest and longest-running diet plan study found the low-carb diet was superior to the Zone, the Ornish--and the U.S. nutritional guidelines.

The low-carb, high-fat Atkins diet gets high marks in one of the biggest, longest head-to-head studies of popular weight-loss plans, beating the Zone, the Ornish diet and even U.S. guidelines. Even so, critics say the results show how hard it is to lose weight and keep it off.