In politics, humanitarian aid, and the social sciences, hunger is defined as a condition in which a person, for a sustained period, is unable to eat sufficient food to meet basic nutritional needs. In the field of hunger relief, the term hunger is used in a sense that goes beyond the common desire for food that all humans experience.

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 subsided for many of the world's population. According to figures published by the FAO in 2019, however, the number of people suffering from chronic hunger increased over the prior four years. This is both as a percentage of the world's population and in absolute terms, with about 821 million afflicted with hunger in 2018.

While most of the world's hungry people continue to live in Asia, much of the increase in hunger since 2015 occurred in Africa and South America. The FAO's 2017 report discussed three principal reasons for the recent increase in hunger: climate, conflict, and economic slowdowns. The 2018 report focused on extreme weather as a primary driver of the increase in hunger, finding rising rates to be especially severe in countries where the agricultural systems were most sensitive to extreme variations in weather. The FAO's 2019 report found there was also a strong correlation between increases in hunger and countries that had suffered an economic slowdown.

Many thousands of organisations are engaged in the field of hunger relief, operating at local, national, regional, or international levels. Some of these organisations are dedicated to hunger relief, while others may work in a number of different fields. The organisations range from multilateral institutions, to national governments, to small local initiatives such as independent soup kitchens. Many participate in umbrella networks that connect thousands of different hunger relief organisations. At the global level, much of the world's hunger relief efforts are coordinated by the UN and geared towards achieving the Sustainable Development Goal 2 of "zero hunger" by 2030.