As obesity rates soar worldwide, the antidote may seem obvious: Eat less! Move more! But the common-sense approach hasnt been terribly effective, prompting some scientists to question the simplicity of the formula.
Although personal decisions and self-control certainly play a large role in weight gain, a burgeoning area of research suggests that other factors, from air pollution to sleep deprivation, might be subtly helping humans pack on the pounds.
Obesity, it turns out, is a complex condition that involves multiple genes and pathways. Scientists are finding that certain exposures or conditions can change the bodys metabolism, disrupt the trillions of microbes working in the gut and alter hormonal levels in ways that affect a persons weight.
Studies have identified nearly a dozen factors besides overeating and inactivity that can help make people fat, including chemicals in the environment. A recent study in the Journal of the American Medical Association found that children and teens with higher levels of the chemical bisphenol A in their urine were more likely to be overweight or obese than others. Its next to impossible to avoid BPA, which is used to make shatterproof plastics and resins and is found in some food packaging, toys, cash register receipts and thousands of other products.
Its an epidemic of 1,000 paper cuts, said Andrew Rundle, a professor of epidemiology at Columbia Universitys Mailman School of Public Health, whose research explores environmental triggers of obesity. For some people, appeals to personal responsibility will work. For others, we have to think about all the systemic things going on. I dont discount personal choice and responsibility. Its just way more complicated than that.
Current public health initiatives on obesity tend to aim at just two targets: Americans lack of physical activity and the marketing practices of the food industry. That somewhat obsessive focus has come at a cost, said David Allison, director of the Nutrition Obesity Research Center at the University of Alabama at Birmingham.
Though the big two play a role, taking a myopic view has led to the neglect of other plausible mechanisms and (to) well-intentioned but ill-founded proposals for reducing obesity rates, Allison wrote in a 2006 study published in the International Journal of Obesity, one of the first to offer creative explanations for weight gain.
Lauren Brush, of Chicago, is one of many who have tried following the conventional advice with little success. Though she says she sticks to a strict 1,200-calorie diet and exercises regularly with a heart-rate monitor, the 24-year-old is still heavier than shed like to be.
I always thought of weight loss as a simple format calories in and calories out, said Brush, who is 5-foot-4 and weighs 160 pounds. Ive found thats not the case whatsoever.
Brush has been fighting to lose weight since childhood. In college, she worked with nutritionists on portion size and making smart food choices. She has been tested for food allergies and tried gluten- and dairy-free diets. She has counted calories and, when that didnt work, ignored them. Doctors have ruled out thyroid issues and problems with her metabolism, she said.
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New triggers: Researchers focus on air pollution, sleep deprivation as weight gain causes
