Controversial Weight Loss Study
Research shows promising results with
By Ridgely Ochs
high-fat, high-protein diet
Staff Writer, Newsday.com
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.
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