I've written a couple of times about the complex causes of obesity. One prominent factor is too much food (especially junk) and too little exercise: excessive calories taken in and too few of them burned up. Sitting around watching television or the computer screen and eating too many munchies and folks get big. The risk can arise early. A major study in the U.S., published this year, established that a third of children who are overweight in kindergarten are obese by grade eight. And almost every child who is obese stays that way into adulthood.
At the same time there is more to obesity than "calories in/calories out". A recent study has tied body mass index (BMI) to pollutants. That investigation suggests that exposure to second hand smoke and roadway traffic may be linked to increased BMI in children and adolescents. Several other studies and reports also raise fears about pollutants and other chemicals and their links to obesity. Endocrine disrupting chemicals (EDCs) to which individuals may be exposed raise grave concerns. They may be connected to obesity in several ways. For example, these substances may increase the number of fat cells, alter the amount of calories utilized while an individual is at rest, and modify the body's mechanisms for appetite and satiety. The White House Task Force on Childhood Obesity underscored the possible effects of EDCs and urged more investigation.