September 2, 2021 | A McMaster University (Canada) study published in Nature Communications demonstrates exposure to the organophosphate insecticide chlorpyrifos promotes obesity development, even at low doses. Obesity generally occurs following a caloric imbalance between food intake, absorption, and energy expenditure. Although various factors can promote obesity, the study results indicate that chlorpyrifos negatively affects metabolic function, playing a role in inhibiting calorie burning or thermogenesis. The suppression of thermogenesis allows calories to accumulate in the adipose tissue rather than convert to energy. Besides genetics, exposure to obesogenic compounds like pesticides can promote obesity development. These compounds routinely cause reproductive, cardiovascular, and endocrine (hormone) issues among exposed individuals, especially farmers. Bruce Blumberg, Ph.D., professor of Developmental and Cell Biology, University of California, Irvine, defines obesogens “as chemicals that inappropriately stimulate the development of fat cells or the storage of fat into those cells, either directly by fiddling with how the cells work, or indirectly altering appetites tied to metabolism.” This study is the first toxicological assessment to investigate obesity and obesity-related illnesses in rodents under thermoneutral conditions, or the temperature at which an organism does not need to regulate body heat. Thermoneutral conditions enable a better prediction of health effects among humans associated with chemical exposure. [Wang, Bo et al. The pesticide chlorpyrifos promotes obesity by inhibiting diet-induced thermogenesis in brown adipose tissue. Nature Communications. 12:5163, 2021.]