In politics, humanitarian aid, and the social sciences, hunger is defined as a condition in which an individual does not have the physical or financial capability to consume sufficient food to meet basic nutritional needs for a sustained period. In the field of hunger relief, the term hunger is used in a sense that surpasses the typical desire for food that all humans experience, also referred to as an appetite. The most severe type of hunger is when malnutrition is widespread, and when people have started dying of starvation through lack of access to sufficient, nutritious food, this results in a declaration of famine.
Throughout history, portions of the world's population have often suffered sustained periods of hunger. In many cases, hunger resulted from food supply disruptions caused by war, plagues, or adverse weather. In the decades following World War II, technological progress and enhanced political cooperation suggested it might be possible to substantially reduce the number of people suffering from hunger. While progress was uneven, by 2015, the threat of extreme hunger had receded for a large portion of the world's population. According to the FAO's 2023 The State of Food Security and Nutrition in the World report, this positive trend had reversed from about 2017, when a gradual rise in number of people suffering from chronic hunger became discernible. In 2020 and 2021, due to the COVID-19 pandemic, there was an increase in the number of people suffering from undernourishment. A recovery occurred in 2022 along with the economic rebound, though the impact on global food markets caused by the invasion of Ukraine meant the reduction in world hunger was limited.