Study: Fast food contributes to obesity
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.
A study published in the Lancet medical journal this week found those who frequently ate fast food gained 10 pounds more than those who did so less often, and were more than twice as likely to develop an insulin disorder linked to 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.
"But there have been very few studies, essentially no long-term studies that have documented the effects of this dietary pattern on the key chronic diseases of Western civilization ¡ª obesity, Type 2 diabetes, heart disease."
"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.
"These findings suggest that fast food as presently consumed can really not be part of a healthful lifestyle," Ludwig said.
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.
"It's quite a powerful message," he said. "I'm happy to see that we have some more solid evidence to substantiate that this is really unhealthy."
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.
While some fast-food chains have begun offering healthier alternatives, including fruit, Astrup said those were only "weak trends in the right direction."
In an essay accompanying the Lancet article, he suggested the chains make a more serious effort to boost the quality of their offerings, by using leaner meats, whole-grain bread, lower-fat fries, low-sugar soft drinks and more vegetables.
McDonald's director of nutrition, Dr. Cathy Kapica, said the issue was not where people ate, but the type of food they chose and the size of portions.
Kapica said McDonald's restaurants had introduced a variety of portion sizes, were serving more salads and fruit, and were providing nutritional information on trayliners, in-store brochures and a Web site.
"The key is to work together to educate and empower people to make smart choices when dining and to encourage physical activity," Kapica said.
Dr. Rudolph Leibel, an obesity expert at Columbia University in New York, said that while the study was sound and its conclusions likely true, it was important not to demonize fast food as the sole cause of the obesity epidemic in wealthy nations.
Fast-food restaurants, he said, are responding to a real societal need ¡ª the inability of many families in which both parents work to find time to cook for themselves.
The restaurants provide a real service by selling cheap, quick food, Leibel said, arguing that the main problem is in the quality and health effects of what they serve.
"I don't think the problem is with fast food per se," he said. "The problem is that it's the wrong kind of food."
The need for improvements there, Leibel said, is the key lesson of the paper, "and the only way to do that really ... is to have an informed consumer."