Views of obesity as a consequence of "lack of willpower" or other behavioral choices, rather than a complex array of biological and other factors, are quite common among undergraduate students. Many undergraduates in prenursing or biology programs have little exposure to the physiology and pathophysiology of obesity, including learning about leptin and other hormones involved in appetite control. I developed materials for teaching about the pathophysiology of obesity in two different pathophysiology courses: one designed as a survey of pathophysiology topics for prenursing majors, and the other designed as an in-depth exploration of the molecular and cellular basis of selected diseases for upper-division biology majors. In the molecular basis of disease course, obesity is covered as part of a unit organized around metabolic syndrome. The discussion includes molecular and cellular mechanisms that link obesity to several other diseases, including type 2 diabetes and atherosclerosis. This article briefly describes the approaches I have taken for teaching obesity to two different undergraduate student populations and lists several resources that may be useful tools for teaching about obesity.