Dietitian Ambler PA

Are low fat diet plans the best for weight loss & lowering cholesterol?

Twenty years ago, when I first started working in the area of vegan nutrition I was a big proponent of very low fat diets, with no saturated fat and little or no unsaturated fat.

At that time, when low fat diet plans like the Ornish diet were especially popular, it really did look like this was the best weight loss diet & diet for lowering cholesterol.

Since then, our understanding about the role of fat in our diet has changed a lot and the situation is far more complex than we originally thought. Anyone who is taking a serious and honest look at the research on diet and heart disease has to question the low fat diet plan approach.

One thing we know (more or less for certain) is that replacing saturated fats in the diet with poly- or monounsaturated fats is as good for lowering cholesterol as removing all fats from the diet. And there is evidence that eating more unsaturated fats is better as far as heart disease is concerned.

Low fat diet plans are associated with a drop in HDL cholesterol, which is the "good" cholesterol. If HDL drops as much as LDL (the bad) cholesterol, there is actually no net gain as far as heart disease is concerned. There are still a lot of questions about how much HDL really matters, but most research suggests that it matters a lot, especially for women.

Reducing all fats in the diet and replacing them with carbohydrates can also boost triglyceride levels. Some studies show that if most of the carbohydrate comes from whole fiber-rich plant foods (as opposed to refined carbs), this doesn't happen. Other studies show it happens no matter what kind of carbohydrates people eat.

Very low fat diet plans also produce a type of LDL-cholesterol that is very small and dense and more easily incorporated into artery-blocking plaque. Because of these effects on HDL levels, triglycerides, and LDL size, many researchers question whether very low fat diets plans are a wise choice for people at risk for heart disease.

Finally, heart disease is not all about lowering cholesterol. There are other diet factors that have nothing to do with blood cholesterol levels but affect the health of the arteries. Some high fat foods-nuts in particular, but also soyfoods - appear to have benefits for heart disease that aren't related to cholesterol levels. Unfortunately some low fat vegan diet plans severely limit these foods or even eliminate them altogether.

And while low fat diet plans have been promoted for weight loss, they tend not to be effective over the long term. Some research shows that including higher fat foods-like nuts or avocado-in meals helps to make reduced-calorie diets more satisfying and actually promotes better long-term weight control.

This isn't to suggest that vegans should have a free...