There is convincing scientific evidence that type of fat have a more important role in determining the risk of coronary heart disease(CHD) than total amount of fat in the diet.(1) However, because of misleading presentation of epidemiological data by some authors(1), the readers might be left with the impression that low-fat, high- carbohydrate diet is the best option for patients with CHD risk.
In fact, high- carbohydrate diets, in the absence of weight loss, can lead to both elevated triglyceride and reduced HDL cholesterol, effects that may be associated with increased risk for CHD.(2) Although these effects may be lessened with dietary fiber and moderate physical activity, they appear to be worse among individuals with insulin resistance.(3)
As reviewed by Kris-Etherton(4) adverse metabolic effects of low fat diet do not occur with substitution of monounsaturated (MUFA) or polyunsaturated (PUFA) fatty acids for saturated and trans-fatty acids. This is also the case for individuals with diabetes, with the added benefit of better glycaemic control.(5)
As predicted by metabolic studies, replacement of saturated fat, and even more so trans fatty acids with either PUFA or MUFA was associated with a larger reduction in risk of CHD than simple reduction of total fat consumption.(6) With respect to weight control, a moderate-fat diet can be as, or even more, effective that lower-fat diet. (6)