Obesity Epidemic: Supersized Nation Still Rules (cont.)

This year's diet research backs up Hill's finding:

Thumbs Up: Thin People Worldwide Eat 'Good' Carbs

A four-continent study showed the same pattern: The thinnest people in the world eat the most carbs. This comes from a survey of 4,000 men and women living in the U.S., U.K., Japan, and China.

"Without exception, a high-complex-carbohydrate, high-vegetable-protein diet is associated with low body mass," reports researcher Linda Van Horn, PhD, of Northwestern University in Evanston, Ill. She presented her findings at the 44th American Heart Association Annual Conference on Cardiovascular Disease Epidemiology and Prevention this year.

This high-carb diet is full of high-fiber vegetables, fruits, beans, and whole grains -- not french fries, not white rice, and certainly not doughnuts. Also, those who exercised more tended to be lighter -- even though they ate more calories, Van Horn reports. High-protein diets were associated with higher body weight, she says.

Thumbs Up: Low Fat for Slow Weight Loss

This year, two studies pitted a low-carb diet against a low-fat diet. The upshot: Low-carb is good for a quick, six-month weight-loss program. But over one year's time, both diet groups lost similar amounts of weight -- 11 to 19 pounds on the low-carb diet and 7 to 19 pounds on the low-fat diet.

One big difference: The low-fat group simply lost weight more slowly, reports study researcher Frederick F. Samaha, MD, with the Philadelphia Veterans Affairs Medical Center. Both groups of dieters had difficulty, however, sticking with their diets.

Thumbs Up: Choose Carbs, Fats Wisely

This year, many of us also learned -- the hard way -- that many low-carb diets don't have staying power. Therefore, it's difficult sticking with them long term, reports Arne Astrup, MD, PhD, head of the Institute of Human Nutrition at the Centre for Advanced Food Research of the Royal Veterinary and Agricultural University in Copenhagen, Denmark.

Astrup reviewed the scientific literature on low-carb diets like Atkins. For up to one year, a low-carb diet is more effective for weight loss than a low-fat diet. However, after one year, low-carb dieters begin regaining weight, he notes. Also, there were side effects: headache, muscle weakness, cramps, and diarrhea.

Thumbs Down: High-Fat Diet Never Good

When is a high-fat diet ever a good thing? Never, nutritionists say. There's big evidence that, when cutting carbs, beefing up fat just won't work. A poll involving 1,200 Minnesota residents found that, from 1999 to 2000, people's diets got better in terms of eating fewer high-fat foods and in daily cholesterol intake. But in 2001 and 2002, those diets got worse and worse.

The culprit? Likely it was the low-carb, high-fat diets that became increasingly popular during those years, says Mayo Clinic researcher Randal J. Thomas, MD. Any plan that increases the amount of saturated fat in your diet is "a problem," he writes. Saturated fat, which comes mostly from animal products, has been strongly linked to heart disease as well as weight gain.

But cut back too much on carbs, and your body -- including your brain -- "is probably suffering from the lack of glucose to burn, and that is disturbing the normal function of tissues," says Astrup.

"Everyone's writing the death certificate on low-carb," Hill tells WebMD. "People who have tried it say they just got tired of if. Eating a 25%-fat diet is something you can do in real life. But you also need one hour of exercise a day. That's the reality, if you want big weight loss. It's the price you pay for obesity. One hour a day keeps off 70 pounds a year."

SOURCES: Kathleen Zelman MPH, RD, director, nutrition, WebMD Weight Loss Clinic. James O. Hill, PhD, director, Center for Human Nutrition at the University of Colorado Health Science Center at Denver. North American Association for the Study of Obesity Annual Scientific Meeting, Las Vegas, Nov. 14-18, 2004. USA Today, Dec. 15, 2004. The New York Times, Dec. 5, 2004. WebMD Medical News: "Low-Carb Diets Work, but Safety Still an Issue." WebMD Medical News: "More Carbs, More Exercise = More Weight Loss." "Low-Carb Diet War: High-Protein vs. High-Fat." Low-Carb, Low-Fat Diets Get Similar Results."

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