The Problem with Low-Fat Diets

updated 02/27/2006 AT 01:00 AM EST

originally published 02/27/2006 AT 01:00 AM EST

JoAnne Sether Menard grew up eating healthy meals—fresh vegetables from an uncle's farm, the occasional duck or pheasant her parents hunted. Then, in 1993, she joined nearly 49,000 other post-menopausal women in a long-term study of the benefits of low-fat dieting, and had a stark realization. "I thought I had a healthy diet," says Menard, 64, an administrator at the University of Washington in Seattle. She lists the foods she had to give up in order to hit the target of 20 percent fat in her diet: chips, doughnuts, fries, cheese, sour cream, salad dressing and butter. "I haven't had butter on bread for 10 years," she says. Yet eating healthy gave Menard more energy to cross-country ski and hike with her husband, Bob Boggs, 59. Even more rewarding, she says, was knowing that taking part in the study would "be helpful for other women's health," she says. "That was important."

Thousands of miles away in Fort Washington, Md., Audrey Allen feels the same way. A daycare provider, Allen, 69, volunteered for the study, part of the government-financed Women's Health Initiative (WHI), and began cooking greens without vegetable oil and eating yolk-free boiled eggs for breakfast. White bread gave way to wheat. Today, Allen says she loves the low-fat eating that helped her shed 20 lbs. "My endurance is good, I am full of energy," she says. "I feel great."

Yet rave reviews from participants are not enough to make a success. On Feb. 8, doctors overseeing the massive study reported that women who had religiously policed their consumption of fat for an average of eight years had no lower incidence of breast cancer, colon cancer or heart disease—conditions once thought to be influenced by fat—than women who ate what they liked. So, time to break out the French fries? No way, say many nutrition experts. For starters, the WHI study was designed years ago, before evidence emerged that the type of fats we eat may be as important as the amount. Of particular concern are so-called trans fats found in junk and fast food (see box, page 90). Furthermore, there are signs that the low-fat diets studied simply didn't go far enough, for long enough: A subset of women who reduced their fat intake the most saw a 22 percent decrease in breast cancer. "We can clearly say that you have some control over the risk of cancer," says Aman Buzdar, a breast cancer specialist at M.D. Anderson Cancer Center in Houston who worked on the study. "We can modify our risk of breast cancer in our kitchen."

Audrey Allen takes the doctor at his word and continues her low-fat regimen. "I am as healthy as three horses, and I look good," she says. "When you put on a dress and it fits properly, it really adds to your self-esteem."


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