Cutting fat alone isn't enough, women advised

If you're a postmenopausal woman, simply trimming the fat from your diet isn't enough to protect against heart disease or breast or colorectal cancer, a government-sponsored study of nearly 50,000 women reports today.

Researchers caution that women shouldn't view the news as an excuse to throw up their hands and go whole hog -- or whole cheesecake or whole bag of chips, for that matter -- with their diets.

If you're overweight or obese, as were most women in the study, you need to not only cut calories but also eat more fruits and vegetables to reduce your risk of heart disease and cancer.

In other words, switching from regular Oreos (160 calories, 60 from fat per serving) to reduced-fat Oreos (150 calories, 40 from fat) won't make much difference. If you must have Oreos, go for the Oreo thin crisps, at 100 calories, 20 from fat, per serving. Better yet, whenever the cookie urge hits, eat an apple or back away from your kitchen and take a walk.

The new findings, which are published in The Journal of the American Medical Association, come from the landmark Women's Health Initiative. The initiative is best known for showing that postmenopausal hormones do not protect against heart attack and stroke.

In addition to the hormone studies, the health initiative also randomly assigned 48,835 postmenopausal women ages 50 to 79 to one of two diet groups. About 60% were told to continue eating what they wanted. The rest were asked to cut fat intake to 20% of total calories, eat at least five servings of fruits and vegetables -- the very minimum set by current government guidelines -- and eat six servings of grains a day. The women were followed for an average of eight years.

Over the course of the study, women in the low-fat group on average reduced their fat intake from about 38% of calories to about 29%. They lost only a pound more than the woman who followed their usual diet, probably because they replaced high-fat foods with lower-fat, simple carbohydrates that contained just as many calories, says Stanford University's Marcia Stefanick, chairwoman of the Women's Health Initiative's steering committee.

Waiting until midlife to cut the fat might be too late as far as cancer risk, says Jacques Rossouw of the National Heart, Lung and Blood Institute and Women's Health Initiative project officer. The hypothesis that a low-fat diet reduces cancer risk arose from studies of countries in which people ate relatively little fat their entire lives, he says.

Other evidence of the importance of early health habits comes from the ongoing Nurses Health Study, which has found that eating too much animal fat is linked to a higher risk of premenopausal breast cancer, says Walter Willett, chairman of the nutrition department at the Harvard School of Public Health.

Dietary advice has changed considerably since the Women's Health Initiative study's launch in 1993. Population studies such as the nurses study have switched the focus from total dietary fat to types of dietary fat and weight, notes Michael Thun, vice president of epidemiology and surveillance research at the American Cancer Society.

For example, the Department of Agriculture's 2005 Dietary Guidelines say it's OK to get as much as 35% of your calories from fat, as long as fewer than 10% of total calories are from saturated fat, and you avoid trans fatty acids.

Says Sidney Smith, a University of North Carolina-Chapel Hill cardiologist: "The dietary strategies are much more than just 'Don't eat fat.' I think it's important to get that message across."

To see more of USAToday.com, or to subscribe, go to http://www.usatoday.com

© Copyright 2006 USA TODAY, a division of Gannett Co. Inc.