In this report, "the Economic Research Service estimates and projects the number of food-insecure people globally, regionally, and in each of the 70 developing countries studied. Food-insecure people are those consuming less than the nutritional target of 2,100 calories a day. The report also measures the food distribution gap (the amount of food needed to raise consumption of each income group to the nutritional requirement) and examines the factors that shape food security. Food security is defined as access by all people at all times to enough food for an active and healthy life. The number of food-insecure people in 70 developing countries rose from 849 million to 982 million in 2006-07, USDA's Economic Research Service estimates in Food Security Assessment, 2007. Food-insecure people are defined as those consuming less than 2,100 calories a day, the nutritional target set by the United Nation's Food and Agriculture Organization (FAO)."
USDA Economic Research Service: http://www.ers.usda.gov/