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"The Low Carb Experts!" SM |
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IN A
SMALL but sure-to-be controversial study, researchers at Schneider
Children's Hospital found that overweight teens on a high-fat,
high-protein diet lost more weight than adolescents on a traditional
low-fat diet.
And, in
contrast to worries that a high-fat diet would increase the risk factors
for heart disease, the teens' cholesterol levels improved, said Dr. Marc
Jacobson, lead researcher and director of the Center for Atherosclerosis
Prevention at the hospital in New Hyde Park. The results of the first
randomized study to directly compare these diets in adolescents were
presented yesterday at the Society for Adolescent Medicine meeting in
Washington, D.C.
The study,
which included 22 people ages 12-18 who were 20-100 pounds overweight,
found that those on the high-fat, high-protein diet lost an average of
19 pounds in 12 weeks, compared to those on a low-fat diet who lost an
average of 8.5 pounds.
Overall
cholesterol levels dropped in both groups, according to Nancy Copperman,
the nutritionist who designed the diets. But triglycerides -- a kind of
blood fat -- fell 33 percent in the high-fat, high-protein diet group,
compared to 17 percent in the low-fat diet group, Copperman said. And
levels of HDL, the so-called "good" cholesterol, also increased more in
the high-fat, high-protein diet group, she said. Kidney and liver
functions were also not affected.
"I think
there's an epidemic of adolescent obesity and we don't have a lot of
good tools to help. The idea of controlling carbohydrates has been
around for 20 years but no one has done a controlled trial," Jacobson
said.
Jacobson said
he wasn't surprised by the greater weight loss in their high-fat,
high-protein group, but "was frankly surprised by the lipids. We didn't
expect that," he said.
In the
high-fat, high-protein diet, teens could have any meats or dairy
products they wished, along with two small salads a day but minimal
carbohydrates. Pasta, juices and bread are not allowed. The low-fat diet
consisted of lean protein, fat-free dairy products and as many fruits
and vegetables as they wanted. The dropout rate was high -- about 30
percent of those initially enrolled -- but about the same in each arm of
the study, Copperman said. The average caloric intake was also higher in
the high-fat, high-protein group compared to the low-fat group (1,830
calories a day vs. 1,100). Those in both groups exercised for 30
minutes, three times a week.
Jacobson said
that the diet appears to work because restricting carbohydrates
suppresses insulin levels, which means the body "can't lay down new fat.
It has to go to fat stores."
Dr. Xavier Pi-Sunyer,
chief of endocrinology at St. Luke's- Roosevelt Hospital Center in
Manhattan and a well-known expert in obesity, urged "a lot of caution"
in interpreting the results of a small, short-term study. "I think if
the assumption is that people stay on these diets, we need to know what
happens to the cardiovascular system over the long term," said Pi-Sunyer.
"I worry about telling kids to go on nothing but a high-fat diet. That's
bad news... We're not talking about crash diets; we're talking about
teaching kids over the long term to eat a healthy diet. This kind of
scares me."
But Dr. Louis
Aronne, director of the comprehensive weight control program at New York
Presbyterian Hospital in Manhattan, applauded the study, saying it was
necessary to look at what appears to work. "With weight loss by any
method you're going to see an improvement in these numbers
[cardiovascular risk factors]. You've got to understand it's very
difficult to stick with these diets and completely eliminate
carbohydrates. The question is what's the kernel of truth that people
could apply in their diets by moving away from starches and moving
toward lean protein and vegetables that can work in the long run?"
Copperman said that after three months the adolescents went on a maintenance diet that included carbohydrates. Most, she said, have been able to keep their weight off 6 to 12 months later. Italics and
bolding are mine... - Dr. Bill |
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