Low-fat diet

A low-fat diet is one that restricts fat and often saturated fat and cholesterol as well. Low-fat diets are intended to reduce diseases such as heart disease and obesity. Reducing fat in the diet can make it easier to cut calories. Fat provides nine calories per gram while carbohydrates and protein each provide four calories per gram, so choosing low-fat foods makes it possible to eat a larger volume of food for the same number of calories. The Institute of Medicine recommends limiting fat intake to 35% of total calories to help prevent obesity and to help control saturated fat intake.

Evidence

Reducing total fat intake leads to reductions in caloric intake, resulting in weight loss or less weight gain. The overall benefit is small but beneficial. With respect to weight loss low-fat diets do not appear to differ from other diets that also reduce overall calories.

Low-fat diets have been promoted for the prevention of heart disease. Lowering fat intake from 35-40% of total calories to 15-20% of total calories has been shown to decrease total and LDL cholesterol by 10 to 20%; however, most of this decrease is due to a reduction in saturated fat intake. Saturated fat has been shown to raise total and LDL cholesterol in a large number of studies and has also been correlated with a higher risk of heart disease.