Very low fat diets.

Current dietary guidelines from both the American Heart Association and the National Cholesterol Education Program recommend restricting consumption of fat to an upper limit of 30% of daily caloric intake. This limit translates into 67 g of fat for small or sedentary individuals who need 2000 calories per day and 100 g of fat for larger or more active individuals who need 3000 calories per day. With the exception of the World Health Organization Study Group, which recommends that 15% of total calories be derived from fat, current guidelines do not specify a lower limit on fat intake. Recommending a lower limit is controversial because of the difficulty in balancing the efficacy of a very low fat diet in decreasing plasma cholesterol levels against the risks of nutrient inadequacy or other adverse effects. Some population subgroups, such as growing children, pregnant women, lactating women, and the elderly, have special needs for essential fatty acids and caloric density. Because weight loss frequently accompanies the initial adoption of a very low fat diet and independently affects blood lipid levels and cardiovascular risk, assessing the effect of the very low fat diet alone is difficult. Step 1 and Step 2 diets are effective in lowering blood cholesterol levels and consequently are advocated as the primary dietary strategy for reducing cardiovascular risk. This statement summarizes the evidence regarding the association of very low fat intake with reduced cardiovascular risk, the quality and quantity of results bearing on this issue, and the effect of very low fat diets on blood lipid levels in the context of potential body weight changes. The statement also contrasts the benefits of very low fat diets with the potentially harmful effects on certain subgroups.