The effects of low-fat, high-carbohydrate diets on plasma lipoproteins, weight loss, and heart disease risk reduction.

Although there is consensus about restriction of dietary saturated and trans fatty acids, cholesterol, and sugars, there is debate about what the optimal total fat and carbohydrate content of the diet should be for weight loss and coronary heart disease (CHD) risk reduction. The overall evidence that dietary composition plays an important role in determining caloric intake is limited. Three recent randomized trials have indicated that low-carbohydrate diets are more effective in promoting weight loss in overweight and obese subjects over 4 to 6 months, but not over 1 year. In our own randomized trial no such differences were noted, and compliance with extreme diets was limited. Moreover little attempt has been made to control for the type of carbohydrate used in the low-fat, high-carbohydrate arms of these trials. Available evidence suggests that restriction of sugars and carbohydrates having a high glycemic index would be preferable to total carbohydrate restriction, and that an increased intake of fiber and essential fats (especially omega-3 fatty acids) is also important for overall heart disease risk reduction.