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Study:
Low-carb Diet Best for
Weight, Cholesterol
 (AP) - The Atkins diet may have proved
itself after all: A low-carb diet and a Mediterranean-style regimen
helped people lose more weight than a traditional low-fat diet in one
of the longest and largest studies to compare the dueling weight-loss
techniques. A bigger surprise: The low-carb diet improved cholesterol
more than the other two. Some critics had predicted the opposite.
"It
is a vindication," said Abby Bloch of the Dr. Robert C. and Veronica
Atkins Foundation, a philanthropy group that honors the Atkins' diet's
creator and was the study's main funder.
However, all three approaches — the low-carb diet, a low-fat diet
and a so-called Mediterranean diet — achieved weight loss and
improved cholesterol.
The study is remarkable not only because it lasted two years, much
longer than most, but also because of the huge proportion of people who
stuck with the diets — 85 percent.
Researchers approached the Atkins Foundation with the idea for the
study. But the foundation played no role in the study's design or
reporting of the results, said the lead author, Iris Shai of Ben-Gurion
University of the Negev.
Other experts said the study — being published Thursday in the
New England Journal of Medicine — was highly credible.
"This is a very good group of researchers," said Kelly Brownell,
director of Yale University's Rudd Center for Food Policy and Obesity.
The research was done in a controlled environment — an isolated
nuclear research facility in Israel. The 322 participants got their
main meal of the day, lunch, at a central cafeteria.
"The workers can't easily just go out to lunch at a nearby Subway or
McDonald's," said Dr. Meir Stampfer, the study's senior author and a
professor of epidemiology and nutrition at the Harvard School of Public
Health.
In the cafeteria, the appropriate foods for each diet were identified
with colored dots, using red for low-fat, green for Mediterranean and
blue for low-carb.
As for breakfast and dinner, the dieters were counseled on how to stick
to their eating plans and were asked to fill out questionnaires on what
they ate, Stampfer said.
The low-fat diet — no more than 30 percent of calories from fat
— restricted calories and cholesterol and focused on low-fat
grains, vegetables and fruits as options. The Mediterranean diet had
similar calorie, fat and cholesterol restrictions, emphasizing poultry,
fish, olive oil and nuts.
The low-carb diet set limits for carbohydrates, but none for calories
or fat. It urged dieters to choose vegetarian sources of fat and
protein.
"So not a lot of butter and eggs and cream," said Madelyn Fernstrom, a
University of Pittsburgh Medical Center weight management expert who
reviewed the study but was not involved in it.
Most of the participants were men; all men and women in the study got
roughly equal amounts of exercise, the study's authors said.
Average weight loss for those in the low-carb group was 10.3 pounds
after two years. Those in the Mediterranean diet lost 10 pounds, and
those on the low-fat regimen dropped 6.5.
More surprising were the measures of cholesterol. Critics have long
acknowledged that an Atkins-style diet could help people lose weight
but feared that over the long term, it may drive up cholesterol because
it allows more fat.
But the low-carb approach seemed to trigger the most improvement in
several cholesterol measures, including the ratio of total cholesterol
to HDL, the "good" cholesterol. For example, someone with total
cholesterol of 200 and an HDL of 50 would have a ratio of 4 to 1. The
optimum ratio is 3.5 to 1, according to the American Heart Association.
Doctors see that ratio as a sign of a patient's risk for hardening of the arteries. "You want that low," Stampfer said.
The ratio declined by 20 percent in people on the low-carb diet,
compared to 16 percent in those on the Mediterranean and 12 percent in
low-fat dieters.
The study is not the first to offer a favorable comparison of an
Atkins-like diet. Research published in the Journal of the American
Medical Association last year found overweight women on the Atkins plan
had slightly better blood pressure and cholesterol readings than those
on the low-carb Zone diet, the low-fat Ornish diet and a low-fat diet
that followed U.S. government guidelines.
The heart association has long recommended low-fat diets to reduce
heart risks, but some of its leaders have noted the Mediterranean diet
has also proven safe and effective.
The heart association recommends a low-fat diet even more restrictive
than the one in the study, said Dr. Robert Eckel, the association's
past president who is a professor of medicine at the University of
Colorado-Denver.
It does not recommend the Atkins diet. However, a low-carb approach is
consistent with heart association guidelines so long as there are
limitations on the kinds of saturated fats often consumed by people on
the Atkins diet, Eckel said.
The new study's results favored the Atkins-like approach less when subgroups such as diabetics and women were examined.
Among the 36 diabetics, only those on the Mediterranean diet lowered
blood sugar levels. Among the 45 women, those on the Mediterranean diet
lost the most weight.
"I think these data suggest that men may be much more responsive to a
diet in which there are clear limits on what foods can be consumed,"
such as an Atkins-like diet, said Dr. William Dietz, of the Centers for
Disease Control and Prevention.
"It suggests that because women have had more experience dieting or
losing weight, they're more capable of implementing a more complicated
diet," said Dietz, who heads CDC's nutrition unit.
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