Food plays an essential role in performance and well-being. Apart from its physiological necessity, food is also a source of pleasure. Since both biological needs for food and psychic satisfaction from food vary considerably among and within populations, coming up with precise, operationalizable measures of food security have proved problematic. Furthermore, the concept of food security encompasses not only current nutritional status but also vulnerability to future disruptions in one’s access to adequate and appropriate food. The complexity of the concept of food security has given rise to scores, if not hundreds, of different definitions of the term “food security.” As a result, there have also been variations in thinking about the proximate manifestations and direct and indirect causes and consequences of “food insecurity,” the complement to “food security.” Food security is commonly conceptualized as resting on three pillars that are inherently hierarchical: availability, access, and utilization. Some agencies, such as the United Nations Food and Agriculture Organization (FAO), have added a fourth dimension: stability. Food insecurity is often used interchangeably with the terms “hunger,” “undernutrition,” and “malnutrition.” Threats to food insecurity may be classified as either “covariate” or “idiosyncratic.” Based on these threats, various interventions have been implemented to promote food security by means of increasing availability (improving agricultural productivity), promoting access (economic growth and assistance programs such as food stamps or vouchers, food aid delivery, food banks, school lunch programs), or improving utilization (supplementary feeding programs, therapeutic feeding programs).