You’ll be eating less fat on the Pian, but there’s no need to cut all of it—in fact, doing so may be counterproductive. In a study from the University of Washington, researchers put 444 men with high LDL on various diets involving different levels of fat.
The result: Reducing total fat to 30 percent of calories from 35 percent and keeping saturated fats at 7to8 percent was as effective at lowering cholesterol as diets with less total fat. In fact, when fat intake dropped to about 20 percent of calories (as some very low-fat proponents recommend), HDL fell and triglyceride levels rose.