Concepts of Hunger

Hunger is usually understood to refer to the distress associated with lack of food. The Food and Agriculture Organization of the United Nations (FAO) defines food deprivation, or undernourishment, as the consumption of food that is not sufficient to provide the minimum amount of dietary energy that each individual requires to live a healthy and productive life, given his or her sex, age, stature and physical activity level.1

Undernutrition goes beyond calories and signifies deficiencies in any or all of the following: energy, protein, or essential vitamins and minerals. Undernutrition is the result of inadequate intake of food in terms of either quantity or quality, poor utilization of nutrients due to infections or other illnesses, or a combination of these factors. These, in turn, are caused by a range of factors including household food insecurity; inadequate maternal health or childcare practices; or inadequate access to health services, safe water, and sanitation.

Malnutrition refers more broadly to both undernutrition (problems of deficiencies) and overnutrition (problems of unbalanced diets, which include consuming too many calories in relation to energy requirements, with or without low intake of micronutrient-rich foods).

In this report, “hunger” refers to the index based on the four component indicators. Taken together, the component indicators (undernourishment, child stunting, child wasting, and child mortality) reflect deficiencies in calories as well as in micronutrients. Thus, the GHI reflects both aspects of hunger.


  1. In estimating the prevalence of undernourishment (FAO, IFAD, and WFP 2015), FAO considers the composition of a population by age and sex, taking into account the range of physical activity levels of the population and the range of healthy body masses for attained height to calculate its average minimum energy requirement. This requirement varies by country—from about 1,650 to more than 1,900 kilocalories per person per day for developing countries in 2014–2016 (FAO 2016c).