Low-Fat Diets and Heart Health

By Avery Hurt

Tempted to abandon a healthy lifestyle because of recent claims that reduced-fat diets don't lower your risk of heart disease? Don't order that double cheeseburger just yet. Guard your heart by eating sensibly, exercising, and ditching cigarettes.

Celebrating the report that low-fat diets don’t reduce heart disease risk is not a good idea. A study published early in 2006 in the Journal of the American Medical Association (with headlines such as “Another Fad Hits the Wall” and “Maybe You’re Not What You Eat”) gives the impression either the recent emphasis on a low-fat diet was just a passing fad, so we can eat all the fat we want without having to worry about our hearts, and/or that health researchers don’t have a clue what we should or shouldn’t eat, so why even make an effort.

Either message would be a dangerous misinterpretation of the study’s findings. Despite alarming headlines, a close look at the actual study reveals that it supports what experts have told us all along.

The study was a part of the Women’s Health Initiative (WHI), a large, long-term research project assessing disease risk and lifestyle factors in women. This portion of the study looked at the dietary patterns of 48,835 women between 50 and 79 years of age over a period of eight years. One much-talked-about result was that a low-fat diet did not appear to reduce the risk of heart disease. The devil is in the details. Although the women in the study reduced their fat intake, the study did not make a distinction between so-called “good” fats and “bad” fats. The women slightly reduced saturated fat and trans fats (the bad ones, from sources such as meat, full-fat dairy, and in the case of trans fats, processed foods), but they also reduced mono and polyunsaturated fats (the good ones, from sources such as olive oil and nuts).

When it comes to fat, the results of the study seem to say that slightly trimming overall fat doesn’t do much good. It’s actually a more complex story than that, which is exactly what the American Heart Association (AHA), the National Heart, Lung, and Blood Institute, and other experts have been saying all along. The AHA’s current dietary guidelines recommend replacing saturated fats and trans fats with mono- and polyunsaturated fats, a concept supported by the WHI study, says Lori Mosca, M.D., director of preventive cardiology at New York-Presbyterian Hospital and chair of the American Heart Association Council on Epidemiology.

In addition, the women in the study did not increase fruits and vegetables to recommended levels and hardly changed the amount of whole grains they ate, says Richard Stein, M.D., director of preventive cardiology at Beth Israel Hospital in New York. “When you look at all of it together, these results are actually pretty consistent with what we’ve been learning in recent years about the role of diet in the development of heart disease,” Stein says. “A basic Mediterranean diet with an emphasis on the kind of fat rather than the total amount of fat is the way to go.”

It is crucial to remember that heart-healthy living comes down to much more than just fat or even diet. “The heart-healthy lifestyle is a package,” Mosca says. That package includes exercise, a healthy eating plan, and abandoning cigarettes.

“The women in this study made little or no change in their physical activity or weight during the course of the study,” says Robert Eckel, M.D., AHA president. Experts agree that both exercise and weight maintenance are necessary components of a heart disease prevention program.

Don’t abandon a healthy lifestyle because of a few attention-grabbing headlines. The basic advice for a sensible diet hasn’t changed, Mosca says.

Basics of a Heart-Healthy Lifestyle

• Eat a diet rich in fruits, vegetables, whole grains, nuts, and low- and nonfat dairy products. Eat fish at least twice a week. Prepare foods with unsaturated oils, such as soybean, canola, and olive oils.
• Exercise regularly. Thirty minutes of moderate activity at least five days a week is recommended.
• Avoid tobacco products.