Food insecurity is increasingly recognized as a major health crisis in the U.S. More than 42 million persons were food insecure in 2015, far higher than the levels preceding the 2007 Great Recession. Decades of research demonstrate that food insecurity diminishes individuals’ overall well-being. The recognition of food insecurity as a health crisis, however, stems from a more recent appreciation of the multiple negative health outcomes and, thus, higher health care costs, attributable to food insecurity. An extensive literature from multiple fields, including agricultural economics, economics, medicine, and nutrition, has emerged in recognition of food insecurity as a health crisis. Among other findings, food insecurity among children is associated with increased risks of some birth defects, anemia, lower nutrient intakes, cognitive problems, and aggression and anxiety. Food insecurity is also associated with higher risks of being hospitalized, poorer general health, worse oral health and with having asthma, behavioral problems, depression, and suicidal ideation. For adults, studies have shown that food insecurity is associated with decreased nutrient intakes; increased rates of mental health problems (including depression), diabetes, hypertension, and hyperlipidemia; being in poor or fair health; and poor sleep outcomes. Food insecurity and poor health are likely linked bi-directionally; that is, it is true both that living in a food insecure household predisposes an individual to poor health, and that poor health predisposes one to living in a food insecure household. After describing how food insecurity is measured, we turn to the multiple causes of food insecurity and potential pathways through which food insecurity leads to these negative health outcomes. Finally, we describe two recently articulated interventions designed to address both food insecurity and its health impact. The first is a targeted increase in benefit levels for supplemental nutrition assistance program (SNAP, formerly known as the Food Stamp Program) enrollees and near eligible households, and the second provides tailored support for food insecure individuals with diabetes.