4 Popular Diets Heart Healthy
Whether it's Atkins, Ornish, Weight Watchers or Zone, it's the pounds that matter
WebMD News Archive
Low-Carb vs. Low-Fat
Dansinger studied 160 overweight men and women who volunteered to
participate in a yearlong diet study. Forty volunteers were assigned to each
diet, he says. Dansinger says he was "just testing the diets, not any
exercise or other lifestyle modifications that are part of the entire diet
program." The researchers also calculated a score to estimate a person's
heart disease risk -- based on common heart disease risk factors, such as
cholesterol and blood pressure.
The benefits from the diets were limited to those who carefully followed
them -- and following the diets was no easy task since the drop out rate for
each diet was 22% at two months. By one year half of the volunteers assigned to
Atkins or Ornish had dropped out as had 35% of those assigned to Weight
Watchers or Zone diets.
Participants following the Atkins, Weight Watchers, and Zone diets achieved
significant reductions in the heart risk score. Those following the Ornish diet
did not show any significant improvement in the heart disease risk score.
Dansinger tells WebMD that this does not mean that the "Ornish diet
doesn't reduce heart disease risk. I have great faith in the Ornish diet, but
it did not meet the statistical test in this study."
Dean Ornish, MD, founder and president of the Preventive Medicine Research
Institute in Sausalito, Calif., was immediately critical of the results.
Ornish tells WebMD that the people assigned to his diet "lost more
weight, had greater reductions in LDL (the 'bad' cholesterol), and were the
only dieters to significantly lower insulin -- even though the Atkins and Zone
diets claim to be specifically designed to lower insulin." Lower insulin
levels indicate a lower risk of developing diabetes, another powerful heart
disease risk factor.
Dansinger, who joined Ornish in fielding questions from reporters, agrees
that the Ornish diet posted impressive results for those who stayed the course
for a year: a nearly 20% reduction in insulin levels while the Atkins diet
dropped insulin by about 8% and the Zone was associated with a 17% drop in
Likewise, the Ornish diet reduced LDL cholesterol by 17%, while the Atkins
dieters reduced LDL by 9%, followed by Weight Watchers dieters at 8% and Zone
dieters at 7%.
Good Cholesterol: How Important Is It?
But the heart disease risk score is based on the ratio between LDL
cholesterol and HDL "good" cholesterol.
"The Ornish diet does not increase HDL, while the other diets do achieve
significant increases in HDL," says Dansinger. The Atkins and Zone diets
increased HDL by 15%, while Weight Watchers posted an 18.5% gain. But the
Ornish diet increased HDL by just 2.2%.
Ornish says HDL is not really a factor because "HDL is really like a
garbage truck that goes around picking up the garbage, which is bad
cholesterol. When you don't have as much bad cholesterol -- garbage -- you
don't need as many garbage trucks." He adds, "raising HDL is easy: eat
a stick of butter. That will drive up your HDL, but it's not good for