With obesity emerging as a leading health threat to Americans, it’s easy to blame a couch-potato culture addicted to calorie-rich foods. But UC Irvine biologist Bruce Blumberg doesn’t believe lifestyle alone explains this phenomenon; he thinks industrial pollutants play a part too. Blumberg (pictured) is among a growing number of researchers exploring how chemicals used in plastics, food packaging, pesticides and cosmetics can trigger dramatic increases in body fat. He has even coined a word for these compounds that corrupt the normal function of metabolic hormones: obesogens. While it’s unclear to what degree these chemicals contribute to the obesity epidemic, what Blumberg and other researchers around the world are finding is troubling. In ongoing studies, Blumberg has identified how obesogens target signaling proteins to prompt a developing fetus to make more fat cells. This can have lifelong consequences, raising the likelihood of body fat accumulation as a person ages and making it more difficult to lose excess weight.