According to a new study from Wake Forest University School of Medicine, trans fats increase fat accumulation at the abdomen, where it does more harm than fat located in other parts of the body. What's more, this accumulation occurs even when total kilojoules are controlled.
Lawrence L. Rudel, Ph.D., professor of pathology and biochemistry and head of the Lipid Sciences Research Program says, "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."
Consumption of trans fats, such as partially hydrogenated vegetable oil raises low-density lipoprotein ("Bad cholesterol"), which increases the risk of heart disease.
In the study, male monkeys were fed two different diets: one with trans fat and one with only mono-unsaturated fats such as olive oil. The group that ate trans fats consumed a similar percentage of trans fats as people who eat a lot of fried food. The kilojoule content and percentage of calories from fat were the same for both groups.
The monkeys that ate trans fats gained 7.2 percent of their body weight, and the monkeys that ate only mono-unsaturated fats gained only 1.8 percent. Interestingly, all the extra weight went to the abdomen, and some fat from other body areas was redistributed to the abdomen. CT scans revealed that the monkeys eating trans fats had significantly more abdominal fat (30% more) than the monkeys eating mono-unsaturated fats.
"We conclude that in equivalent diets, trans fatty acid consumption increases weight gain," said Kylie Kavanagh, DVM.
Trans fats are found in margarine, vegetable shortenings, snack foods like crackers, cookies, and cakes, and anything fried or made with partially hydrogenated oil.