Older women who ate less
fat and more carbohydrates lost about 2 pounds over seven
years, a large study showed.
While one obesity expert called the results disappointing,
the lead author of the research said it refutes claims
by promoters of the Atkins and Zone diets that low-fat
diets are partly behind America's obesity epidemic.
"It will help people to understand that the weight gain
we're seeing in this country is not caused by the lower-fat
diets," said study author Barbara V. Howard of MedStar
Research Institute, a nonprofit research group.
However, the skimpy weight loss after seven years won't
satisfy people looking for a cure for obesity, said Dr.
Michael Dansinger, an obesity researcher at Tufts-New
England Medical Center who was not involved in the study.
"This is like losing the Super Bowl but claiming a second
place victory," Dansinger said. "The results are disappointing
in the context of a country trying to battle obesity."
The study, appearing in the Journal
of the American Medical Association, included more
than 48,000 women, ages 50 to 79. They were followed for
an average of seven years and six months.
One group of women lowered the fat in their diets while
increasing fruits, vegetables and whole grains. The other
group didn't change their diets significantly.
The target fat content of the diet was 20 percent, but
the women on the diet actually got about 30 percent of
their calories in fat; their previous fat intake was about
39 percent.
The women on the diet increased their carb calories from
44 percent to 53 percent, while the women not on the diet
stayed at about 44 percent carbs.
The low-fat group lost, on average, 4.8 pounds in the
first year, then regained most of that weight. The non-diet
group stayed at about the same weight over the seven years.
The women were part of the Women's Health Initiative,
a research project of the National
Institutes of Health that involves thousands of
postmenopausal women across the country. Other WHI studies
have uncovered the risks of taking hormones.
Weight loss was not the original focus of the study,
Howard said. Other findings on the low-fat diet's effect
on heart disease and cancer will be released this year,
she said.
But researchers realized their data could answer charges
made by popular diet promoters who drew a link between
obesity and recommendations of low-fat eating plans by
health organizations and the government. Low-fat diets
promote foods like grains and pasta, which are mostly
forbidden by low-carb diets.
"The Zone" diet author Dr. Barry Sears, after reading
the new study, said he stands by his belief that the recommended
low-fat, high-carb diet caused Americans to gain weight.
He noted that women on the low-fat diet in the study
lost only a fraction of a pound per year, on average,
and they added 1.6 centimeters — about a half-inch
— to their waist circumferences. The other group
added 1.9 centimeters.
"I was struck by what the study didn't say," Sears said.
Dansinger, who co-authored an editorial that accompanies
the study, said his research has shown that diets like
Atkins and The Zone work, but are hard to stay on.
"People who succeed at maintaining a dramatic weight
loss have changed their mindset and priorities and have
made exercise and healthy eating among the top priorities
in their lives," he said.
