A new study gives scientific clout to a conclusion many already see as obvious: Eating lots of fast food makes you fat and increases the chance of developing diabetes.
"Fast food is commonly recognized to have very poor nutritional quality," said Dr. David Ludwig, director of the obesity program at Children's Hospital Boston and the senior author of the study.
"In the absence of such data, the fast-food industry continues to claim that fast food can be part of a healthful diet," he said.
Ludwig's U.S.-based team followed 3,000 young people enrolled in a study of cardiac health over 15 years, giving them medical checkups and asking questions about diet, physical activity and other lifestyle factors.
Even after the scientists used statistical techniques to cancel out the impact of the other factors, those who said they visited fast-food outlets twice a week or more gained 10 pounds more over the course of the study than those who ate fast food less than once a week.
They also had more than double the chance of developing insulin resistance, considered a predictor of Type 2 diabetes, the form of the disease linked to obesity.
Arne Astrup, an obesity expert at the Royal Veterinary and Agricultural University in Copenhagen, Denmark, said the study was the first long-term look at the relationship between fast-food consumption and diabetes.
No time to cook Astrup said the huge portions at most fast-food restaurants and the high caloric density of their food were probably responsible for the obesity link.
Because even small amounts of fast food contain lots of calories, people consume a great deal without feeling full and soon get hungry again and eat more, he said.