Young adults who eat frequently at fast-food restaurants gain more weight and have a greater increase in insulin resistance in early middle age, according to a large multi-center study funded by the National Heart, Lung, and Blood Institute (NHLBI) and published in the January 1 issue of The Lancet*.
After 15 years, those who ate at fast-food restaurants more than twice each week compared to less than once a week had gained an extra ten pounds and had a two-fold greater increase in insulin resistance, a risk factor for type 2 diabetes.
"Obesity and diabetes are on the rise in this country and this important study highlights the value of healthy eating habits," said NHLBI Acting Director Barbara Alving, M.D.
Despite some of their recent healthful offerings, the menus still tend to include foods high in fat, sugar and calories and low in fiber and nutrients," said lead author Mark Pereira, Ph.D., assistant professor of epidemiology at the University of Minnesota.
People need to evaluate how often they eat meals at fast-food restaurants and think about cutting back, according to Pereira.
One reason for the weight gain may be that a single meal from one of these restaurants often contains enough calories to satisfy a person's caloric requirement for an entire day.
Researchers found that the adverse impact on participants' weight and insulin resistance was seen in both blacks and whites who ate frequently at fast-food restaurants, even after adjustment for other lifestyle habits.
The participants, who were part of the Coronary Artery Risk Development in Young Adults (CARDIA) study, received dietary assessments over a 15-year period.
Salads and grilled foods tend to be lower in fat than fried foods, she said.