Dear Earthtalk: I've heard that, above and beyond our bad eating and lifestyle habits, some chemicals in everyday products are contributing to the obesity problem. Can you explain?--Alyssa Israel, Fairfield, CT
Obesity is a huge problem in the U.S. and other industrialized countries. According to the U.S. Centers for Disease Control and Prevention, obesity rates have doubled for American adults and tripled for kids and teenagers aged six through 19 since 1980. Today, 31 percent of American adults and 15 percent of youngsters are classified as overweight.
The rise in obesity and related health problems like diabetes is usually attributed to an abundance of high-calorie food coupled with the trend toward a more sedentary lifestyle, but there is more to the story. A growing number of researchers believe that certain chemicals collectively known as "obesogens" may be a contributing factor to the growing obesity epidemic. Exposure to these chemicals has been shown to interfere with the way we metabolize fat, leading to obesity despite otherwise normal diet and exercise.
Bruce Blumberg, a biology professor at the University of California at Irvine, first coined the term "obesogen" in 2006 after discovering that certain tin-based compounds known as organotins predisposed lab mice to weight gain. In the intervening years, hundreds of research studies have found similar connections between weight gain in humans and exposure to organotins as well as several other common chemicals found in everyday consumer products, agricultural pesticides and even some drinking water.
The National Institute of Environmental Health Sciences (NIEHS) reports that as many as 20 synthetic chemicals--from the BPA in plastic food storage containers and the lining of cans to phthalates used in the manufacture of non-stick coatings to the parabens in many personal care products--have been shown to cause weight gain in humans, mostly from exposure in utero or as infants. These early effects can last a lifetime, permanently altering one's metabolic "set points" for...