Weight Watchers, the high-fat Atkins diet, the extremely low-fat Ornish diet
and the high-protein, moderate carbohydrate Zone diet all help people lose
weight and all reduce cholesterol, but in different ways, the researchers said.
"On average, participants in the study reduced their heart disease risk by 5
percent to 15 percent," Dr. Michael Dansinger of Tufts University in Boston told
a meeting of the American Heart Association.
"Instead of saying there is one clear winner here, we are saying they are all
winners."
And, as might be expected, the closer dieters followed the plans, the more
weight they lost.
Those who stuck it out for a full year lost, on average, 5 percent of their
body weight -- or about 10 to 12 pounds.
While the dieters reduced heart disease "risk factors" such as cholesterol
levels, overall blood pressure did not drop much and the study did not last long
enough to see if this translated into a lower long-term risk of heart disease.
Instead, the researchers used statistics that show lowering cholesterol by a
certain amount, for instance, reduces the risk of heart disease overall.
Dr. Robert Eckel of the University of Colorado, who heads the Heart
Association's nutrition committee, said the message is clear -- lose weight
however you can to reduce your risk of heart disease.
WEIGHT REDUCTION
"I think weight reduction trumps a lot of other stuff," Eckel said.
For the study Dansinger and colleagues chose 160 overweight people and
randomly assigned 40 to each of four different diets. They weighed an average
220 pounds (100 kg) and needed to lose between 30 and 80 pounds.
All agreed to follow the diets to the best of their ability for two months,
although none were enrolled in the full programs that Weight Watchers and Dr.
Dean Ornish advocate.
They include exercise, group meetings and food diaries for Weight Watchers
and stress reduction for the Ornish diet.
After two months 22 percent of the dieters had given up. After a year, 35
percent dropped out of Weight Watchers and the Zone diets and 50 percent had
quit the Atkins and Ornish plans.
Dansinger and other researchers said the study suggested there is no
one-size-fits-all diet best for everyone.
"The type of person who is going to go for a low-fat, vegetarian diet is not,
in my experience, the kind of person who is going to go for a high-meat diet,"
Dansinger said.
But for people with high cholesterol levels, the Ornish diet might be the
most beneficial, Dansinger said.
"The Ornish diet, low-fat vegetarian, was best for lowering the bad LDL
cholesterol, while other diets were better at raising the good HDL cholesterol,"
Dansinger said. Low density lipoprotein cholesterol is the stuff that clogs
arteries, while high density lipoprotein carries fat out of the blood.
"Atkins reduced LDL 8.6 percent, Zone 6.7 percent, Weight Watchers 7.7
percent and Ornish 16.7 percent," Dansinger said in a statement afterwards. He
said the Atkins and Zone diets diet raised HDL by about 15 percent, Weight
Watchers by 18.5 percent, and Ornish by 2.2 percent.
Ornish said doctors often place too high a value on high HDL levels. "If you
reduce fat, there is less garbage, less saturated fat and cholesterol, so your
body needs less garbage trucks," he said.
But Dansinger said his study was one of several that has suggested the
high-fat Atkins diet, in the short-term, does not raise the risk of heart
disease.
