June 28, 2006
What do pollution, birth-control pills and air conditioners have in common?
Your expanding waistline, some scientists suggest.
In a controversial new look at the causes of America’s obesity epidemic, 20 researchers from eight states report that 10 often-overlooked factors could contribute to our growing girth. But proving that — and doing something about it, if true — will be another matter.
Pollution? It can disrupt the body’s hormones and cause it to store more fat, they said.
Birth-control pills? Along with steroids, antidepressants and some other medications, they tend to promote weight gain.
Air conditioners? We burn more calories when we’re hot, the scientists said, and tend to eat less then, too.
Even doing good may have a downside: Smokers tend to weigh less than non-smokers. As smoking rates decline, the needle on the national scale creeps up.
Not getting enough sleep can also do dieters in: Sleep deprivation is associated with increased appetite.
The study, which appears in Monday’s International Journal of Obesity, immediately met with praise from some experts who have long argued obesity is probably due to many factors. But it was criticized by others, who said the paper downplays the roles that calorie consumption and exercise play.
“We are not saying for an instant that what you eat and how much energy you expend don’t matter. They are the primary determinants of how fat one is,'’ stressed David B. Allison, director of the University of Alabama at Birmingham’s Clinical Nutrition Research Center and one of the study’s authors. “What we are saying is there are many influences on how fat one becomes.'’
During the past two decades, obesity has become much more prevalent in the United States, with an estimated 30 percent of adults — more than 60 million people — now classified as obese, according to the Centers for Disease Control and Prevention.
Obesity is associated with an increased risk of a number of diseases, including type 2 diabetes, coronary heart disease and some cancers.
As obesity rates soar, attention has focused on the accessibility of snack foods and sodas and the reduced opportunities for physical activity in our society.
But the study authors question whether that is short-sighted, possibly resulting in “well-intentioned but ill-founded proposals for reducing obesity rates'’ at a time when all the causes aren’t clear.
Many of the factors they cite in their report, which is a review of more than 100 obesity studies, aren’t easy to control.
Children born to older mothers may be set up to be overweight. The same may be true if their grandmothers overate before giving birth, the researchers said.
Curvy, slightly overweight women tend to be more fertile than their string-bean skinny counterparts and reproduce more, the study also explains, meaning that future generations of children are more likely to inherit fat genes.
Reason No. 10? People are slightly more likely to choose mates of their own body style — thin with thin, rotund with rotund. Even though the effect is small, the scientists said, this could gradually skew society toward fatness.
“They left out global warming. I’m saying that in jest,'’ said a skeptical Dr. Thomas Robinson, director of the Center for Healthy Weight at Lucile Packard Children’s Hospital at Stanford.
While Robinson said some of the explanations, such as sleep deprivation and smoking cessation, are plausible causes of weight gain, others may have little if any influence. Further, they do little to inform the public on how to lose weight and keep it off.
“These are really far-fetched explanations for something that’s really simple: People are eating more and moving less,'’ agreed Marion Nestle, professor of nutrition at New York University and author of “What to Eat.'’
“I think this is a report that will get a lot of attention because no one wants to talk about calories. Everyone is looking for an excuse.'’
The study doesn’t attempt to address just how much each of the 10 factors influences obesity, Allison said. Nor does it focus on all the possible causes. Working the swing shift and not breast-feeding have been implicated in some studies. So has an increase in childhood depression, a decrease in dairy consumption and eating meat from livestock that were fed hormones.
“We do not claim that all of the additional explanations definitely are contributors,'’ the study authors wrote, but only that they are as plausible as diet and exercise “and deserve more attention and study.'’
J. Justin Wilson, a research analyst for the Center for Consumer Freedom in Washington, agreed. The center is a non-profit coalition of consumers, restaurants and the food industry.
“The media and activists have homed in on a few unfavored food groups — fast food, soda, high fructose corn syrup'’ he said. “They seem to ignore that obesity is far more complicated than that, and this study is an indication of that.'’
Posted by toshko under Mircette News | Comments (0)
