TUESDAY, June 13, 2006 (HealthDay News) -- Diets that are high in trans fats may lead to weight gain around the middle, even when calories are reduced, a new U.S. study finds.
Researchers at Wake Forest University School of Medicine studied monkeys given a diet high in trans fats and low in calories to see how it affected their body weight.
"Diets rich in trans fat cause a redistribution of fat tissue into the abdomen and lead to a higher body weight even when the total dietary calories are controlled," Lawrence L. Rudel, a professor of pathology and biochemistry and head of the Lipid Sciences Research Program, said in a prepared statement.
The monkeys were studied for six years, and all were male. Their diets all had the same amount of daily calories and all had 35 percent of calories from fat. One group was fed a diet with 8 percent of calories from trans fat, while the other group received the same percentage from monounsaturated fats, found in foods like olive oil. The diets were modeled after a typical Western-style diet, and the amount of trans fats fed to the monkeys was about the same as an average person eating a diet high in fried foods.
"We believed they couldn't get obese because we did not give them enough calories to get fat," explained Rudel.
Researchers saw the body weight of the monkeys fed the diet high in trans fats increase by 7.2 percent, while the monkeys fed monounsaturated fats only had a 1.8 percent increase in body fat. The extra fat in all of the monkeys was concentrated in the abdomen, and CT scans showed greater concentrations of abdominal fat deposits in the trans-fat diet monkeys -- 30 percent higher than the monounsaturated diet group.
Results of the study were presented Monday at the American Diabetes Association's annual scientific sessions, in Washington, D.C.
"We conclude that in equivalent diets, trans fatty acid consumption increases weight gain," researcher Dr. Kylie Kavanagh said in a prepared statement. "In the world of diabetes, everybody knows that just 5 percent weight loss makes enormous difference. This little difference was biologically quite significant."
For tips on heart-healthy diets, head to the American Heart Association.