Researchers have found that immune cells in the brain may trigger overeating and weight gain in response to diets rich in fat, according to a new study in mice published Wednesday in the journal Cell Metabolism. The researchers from the University of California, San Francisco, and the University of Washington Medical Center found a link between brain inflammation and obesity in mice. Obesity is common and growing in prevalence, especially in segments of the population worldwide that have poor access to healthy nutrition, affordable health care and optimal education to learn how to adopt a healthy lifestyle, says Dr. Suneil Koliwad, assistant professor of medicine at the UCSF Diabetes Center and the Gerold Grodsky chair in diabetes research at the university.