Conventional wisdom says that weight gain or loss is based on the energy balance model of "calories in, calories out," which is often reduced to the simple refrain, "eat less, and exercise more." But new research reveals a far more complex equation that appears to rest on several other important factors affecting weight gain. Researchers in a relatively new field are looking at the role of industrial chemicals and non-caloric aspects of foods -- called obesogens -- in weight gain. Scientists conducting this research believe that these substances that are now prevalent in our food supply may be altering the way our bodies store fat and regulate our metabolism. But not everyone agrees. Many scientists, nutritionists, and doctors are still firm believers in the energy balance model. A debate has ensued, leaving a rather unclear picture as to what's really at work behind our nation's spike in obesity.
Bruce Blumberg, professor of developmental and cell biology and pharmaceutical sciences at the University of California, Irvine, who coined the term "obesogen," studies the effect that organotins -- a class of persistent organic pollutants that are widely used in the manufacture of polyvinylchloride plastics, as fungicides and pesticides on crops, as slimicides in industrial water systems, as wood preservatives, and as marine antifouling agents -- have on the body's metabolism. Organotins, which he considers to be obesogens, "change how your body responds to calories," he says. "So the ones we study, tributyltin and triphenyltin, actually cause exposed animals to have more and bigger fat cells. The animals that we treat with these chemicals don't eat a different diet than the ones who don't get fat. They eat the same diet -- we're not challenging them with a high-fat or a high-carbohydrate diet. They're eating normal food, and they're getting fatter."