• February 27, 2006
• Vol. 65
• No. 8

The Problem with Low-Fat Diets

By Bob Meadows

A Landmark Study Suggests They Don't Work for Cancer and Heart Disease. But Don't Reach for the Ice Cream Just yet

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."

FOR MORE INFORMATION, GO TO: www.americanheart.org www.cfsan.fda.gov

• Contributors:
• Macon Morehouse/Washington,
• D.C.,
• Melody Simmons/Washington,
• D.C..

More From This Article

The Low-Fat Diet Study

What You Need to Know

I seem to read about a big diet study every week. What's important about this one?

It tells us that simply cutting fat from your diet (which, as we all know, is not that simple) is not enough to protect you from breast cancer, colon cancer and heart disease. Experts say we must do more: watch our calories, eat a balanced diet and stay active.

But didn't the new study say a low-fat diet isn't worth the effort?

The diet examined in this study was designed more than a decade ago. Today, nutritionists suspect that certain fats, particularly those found in processed foods, are more damaging than others (see box, right). "A big hamburger with cheese every day is going to get you into trouble, not just with cancer but with other diseases too," says Len Lichtenfeld, deputy chief medical officer of the American Cancer Society.

Do the study results apply to younger women? To men?

Most likely. Researchers in this study looked at post-menopausal women over the age of 50. But previous diet studies haven't revealed differences based on age or gender.

Are there any lifestyle changes I can make to prevent these diseases?

Absolutely. "Don't eat red meat more than two times a week, don't smoke, exercise moderately, take a multi-vitamin and no more than one alcoholic beverage a day," says Charles Fuchs, medical oncologist at the Dana-Farber Cancer Institute.

Does how much I eat matter more than what I eat?

Probably. Everyone should strive for a balanced diet, but limiting yourself to smaller portions of junk food could also help your health. "The bad things you are eating have less of an impact if you're not eating too many calories," says New York University nutritionist Marion Nestle.

What does this study mean for diets like Atkins, South Beach and Weight Watchers?

People turn to those other diets primarily for weight loss, not protection against disease, and none of them have been studied this extensively over the long term. The WHI diet did cause women to lose a small amount of weight and produced no health problems.

The Skinny on Trans Fats

Since Jan. 1 federal law requires foodmakers to list the quantity of trans fats—which form when liquid cooking oil is converted into solid shortening—on food labels. If the new labels sound like a good idea, they are. Trans fats lower the amount of good cholesterol (HDL) while raising the amount of bad (LDL). But the labels can also be tricky. The FDA allows foods with fewer than 0.5 percent grams of trans fat per serving to be labeled free of the fats. "So when people choose snack type foods that are easy to overconsume," explains nutritionist Elisa Zied, "this can lead to a sizable helping of trans fats." Solution: Watch out for another ingredient—"partially hydrogenated oil"—on labels. If it's present, trans fats are too.