For diet results, moderate-fat beats low-fat
June 6, 2000
By Nanci Hellmich, USA TODAY
RESTON, Va. - Dieters lose more weight and have an easier time sticking with a moderate-fat diet than with a low-fat diet, says a pilot study being presented today at a dietary fat conference here.
Exactly how much fat is best for health and weight loss is being discussed at the American Heart Association (AHA) conference, co-sponsored by Oldways Preservation & Exchange Trust and the American Cancer Society.
Currently, the AHA is reviewing its dietary guidelines, including the recommendation on the amount of fat that should be consumed.
In the new study, researchers with Harvard-affiliated Brigham and Women's Hospital in Boston followed 101 adults, mostly women, for 1 1/2 years.
They divided the participants into two groups. Half of the people followed a diet with 35% of calories from fat that was mostly monounsaturated (olive oil, canola oil, peanut butter, avocado, nuts) and some polyunsaturated fats (corn oil, soybean oil). They limited saturated fat (fatty meats, whole dairy products) to about 5% of their intake. It was based on a Mediterranean-style diet. The other half were instructed to limit their diet to no more than 20% of calories from fat.
Those participants did that by doing things such as using non-stick cooking sprays and fat-free salad dressings.
Both groups were asked to watch calories. Women were told to keep their calories to about 1,200 a day; men were told to try to stick with 1,500 calories during the weight-loss phase. After the first six months, both groups began consuming more calories.
After 18 months, 54% of those on the moderate-fat diet were still participating in the study, compared with 20% of those on the low-fat diet.
People who stuck with either plan lost about the same amount: 11 pounds in six months. But at 18 months, those on the moderate-fat diet had kept their weight off, and those on the low-fat diet began to gain some back.
Participants in the moderate-fat group told the researchers that they "didn't feel like they were dieting," says Kathy McManus, director of the department of nutrition at Brigham and Women's Hospital. "They were eating regular, healthy foods and just trying to cut back on the amount."
Those in the moderate-fat group were encouraged to eat nuts in the late afternoon instead of grabbing rice cakes, pretzels or low-fat cookies.
The moderate-fat dieters actually increased the amount of vegetables they consumed by one serving a day, possible because they were able to use olive oil and vinegar or high-fat salad dressings on their salads, and they used olive oil when cooking vegetables, McManus says.
John Foreyt, an obesity researcher at Baylor College of Medicine in Houston, says this is an "important finding, assuming there are more studies that back it up."