Rice is the primary food staple for about half of the world's people and, along with maize and wheat, provides two-thirds of all food energy. Fruits, vegetables, and animal products provide variety and vital nutrients, but are a relatively small share of the diet in most countries, especially in the developing world, where three-fourths of the Earth's population live. This is well over the minimum daily calorie requirements even for people whose jobs involve hard physical labor. In fact, if everyone adopted a vegetarian diet and no food were wasted, current production would theoretically feed 10 billion people, more than the projected population for the year 2050. But the world's food supply is not distributed equally throughout the world, within countries, and sometimes even within households.
Poverty is the major cause of hunger throughout the world.
Many low-income countries do not grow enough food to feed their residents, and cannot afford to import enough food to make up the difference. Within the developing world, an estimated 843 million people, including 200 million children, do not receive enough calories to ensure physical health and development. Millions more people consume the minimum number of calories, but fail to get the necessary protein and essential vitamins and minerals to lead a healthy life. The number of malnourished often swells during times of drought, or when regular networks of food supply are disrupted by natural disaster or political violence. Famines can occur even when there is plenty of food.