Mediterranean Diet: Better, Not Best?

Gayl J. Canfield, PhD, RD


March 19, 2013

In This Article

Healthy "Low-Fat" Diets

A substantial body of research exists that has documented the heart-healthy benefits of 2 well-known low-fat diets, Pritikin and Ornish. In fact, the data are so strong that Medicare now covers cardiac rehabilitation programs based on the Pritikin and Ornish plans for people with a history of cardiovascular disease.[2] Both programs also include exercise and lifestyle-change components.

The Ornish Program has been proven to regress heart disease,[3,4] and the Pritikin Program has been proven to significantly reduce many modifiable risk factors for cardiovascular disease, including low-density lipoprotein (LDL) cholesterol, triglycerides, blood glucose, hypertension, inflammatory markers such as C-reactive protein, and excess weight/obesity.[5,6,7]

Both programs recommend an eating plan with about 10% to 15% of calories coming from fat, and both emphasize hearty consumption of fruits, vegetables, whole grains, and legumes such as beans. The Ornish Program is completely vegetarian, whereas the Pritikin Program allows up to 4 oz of animal protein daily, such as omega-3-rich fatty fish, skinless white poultry, or lean meat such as bison.

Both of these programs are a far cry from the "low-fat" diets of the 1980s and 1990s, many of which were anything but healthy. Often, the "low-fat” and "fat-free" products people were eating (remember "fat-free" cookies?) were essentially junk food themselves -- very high in sugar, salt, and/or refined white flour.

Low-fat plans such as Pritikin and Ornish, by contrast, focus on real food -- whole, minimally processed, naturally fiber-rich foods that, as Michael Pollan wrote in his superb book In Defense of Food, "are foods our great grandmothers would have recognized as food."

Another low-fat diet that has proven to be particularly beneficial for blood pressure control is the DASH (Dietary Approaches to Stop Hypertension) diet. Several studies funded by the National Institutes of Health (NIH) have found that the DASH diet lowers blood pressure as well as or better than medications. DASH also promotes menus that are high in fruits, vegetables, whole grains, and beans; low in fats, salt, red meats, and sweets; and moderate in fish, poultry, nuts, and low-fat or nonfat dairy foods.

In one study, NIH researchers found that 8 weeks of following the DASH regimen resulted in reductions in blood pressure in all groups of men and women studied.[8] Even those who started with a normal blood pressure (systolic pressure < 120 mm Hg) saw improvements. The biggest reductions in blood pressure were observed in the individuals who were hypertensive (systolic pressure >140 mm Hg), emphasizing the fact that diet is a major factor in determining blood pressure in most hypertensive patients.

In another DASH study, 3 groups of people followed the diet but took in varying levels of sodium (3300 mg, 2400 mg, or 1500 mg per day). The researchers found that the biggest drops in blood pressure occurred in the group on the 1500 mg/day diet.[9]