By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

A typical American diet that is high in saturated fat (SFA, which is mainly animal fat) is known to be bad for the heart, and some enthusiasts, such as Dean Ornish, have proposed that all fat is bad, and that a low fat-high carbohydrate diet is the answer. Not only is this unpalatable for many people, but there is mounting evidence that substituting mono-unsaturated fats (MUFA) for saturated fats may produce a greater reduction of risk than simply eliminating all fats.

The Science Advisory Committee of the American Heart Association has endorsed the use of MUFA, which are a major component of the Mediterranean diet (olive oil is rich in MUFA). Several studies have shown that when a high-saturated fat American diet is replaced either by a very low-fat Ornish-type diet or one in which saturated fat is replaced by MUFA; both diets will lower total and LDL cholesterol. But the Ornish diet raises triglycerides and lowers HDL, neither of which is desirable. In contrast, the high MUFA diet does not affect triglycerides or HDL. Poly-unsaturated fats (PUFA) may also have beneficial effects.

High MUFA diets may also benefit patients with diabetes.

Foods that are high in MUFA include olive oil, canola oil, nuts, avocados, sesame seeds, and tahini.

The recommendation is for a diet that contains 15% of calories from MUFA, 8% from PUFA, and 7% from SFA. This gives a total fat intake that is 30% of total calories. The typical American diet has 35-40% of calories from fat, most of which is from SFA.

The bottom line is that you don’t have to give up all fats to avoid heart disease; there are good fats and bad fats.