The United Nations on Tuesday revised its estimates of the number of chronically malnourished people in the world from 1 billion to nearly 870 million, according to a report from the UN News Centre.

Despite the decline, the State of Food Insecurity in the World 2012 (SOFI) reports that one in 8 people are malnourished, including more than 100 million children who are underweight.

According to the BBC, the UN defines hunger as the consumption of fewer than 1,800 kilocalories a day, the minimum required to live a healthy and productive life.

The new figure is due to "a new measurement methodology," Eric Reguly of The Globe and Mail reported Tuesday. Factors include new thresholds for caloric undernourishment and "episodic" malnourishment.

The report was jointly published by the Food and Agriculture Organization (FAO), the International Fund for Agricultural Development (IFAD) and the World Food Programme (WFP).

New estimates indicate the number of hungry declined more sharpy between 1990 and 2007 than previously believed — by 132 million, or from 18.6 percent to 12.5 percent of the world's population.

The vast majority of the hungry – 852 million – live in developing countries in Asia and Africa. While the number of malnourished people declined by almost 30 per cent in Asia and the Pacific over the past two decades, Africa experienced an increase from 175 million to 239 million people during the same period.

Childhood malnutrition is a cause of death for more than 2.5 million children each year, according to the report's forward.

“In today’s world of unprecedented technical and economic opportunities, we find it entirely unacceptable that more than 100 million children under five are underweight, and therefore unable to realize their full human and socio-economic potential, and that childhood malnutrition is a cause of death for more than 2.5 million children every year,” says the report’s foreword, written by FAO Director-General José Graziano da Silva, IFAD President Kanayo F. Nwanze and WFP Executive Director Ertharin Cousin. “We note with particular concern that the recovery of the world economy from the recent global financial crisis remains fragile. We nonetheless appeal to the international community to make extra efforts to assist the poorest in realizing their basic human right to adequate food. The world has the knowledge and the means to eliminate all forms of food insecurity and malnutrition."