Nearly 6 million children die because of malnutrition every year, mainly in developing countries, though there exists the availability of relatively cheap solutions that could improve global nutrition.
While low- and middle-income countries bear the brunt of the problem, malnutrition affects some rich countries as well, said the report by the Population Reference Bureau, a Washington policy research group.
The bureau's "2007 World Population Data Sheet" and two companion reports provide up-to-date demographic, health and environmental data for all the countries and major regions of the world.
The report said poor nutrition during the mother's pregnancy and the baby's early years causes severe and irreversible mental and physical damage.
Bill Butz, president of the Population Reference Bureau, said the public often does not consider the deadly toll of malnutrition among children "because it does not kill young children directly, as does pneumonia or diarrhea.
"Many of these deaths could be averted through nutrition measures that are known to be effective, often at low cost," Butz said.
"Malnutrition often increases susceptibility to disease, while ill health exacerbates poor nutrition," the report said. "For countries ravaged by the HIV/AIDS epidemic, malnutrition appears to increase vulnerability to infection and render retroviral treatments less effective."
Despite some important progress, the report said, about 30 percent of children in low- and middle-income countries are underweight. The largest problems are in South Asia and sub-Saharan Africa.
For example, almost half the children are underweight in some Indian states.
To improve nutrition In the short term, the report said, countries should begin monitoring and promoting growth, changing nutritional behavior, improving communication with people at risk of malnutrition and introducing iodized salt.
Later they could establish community-based nutrition programs that target young children, adolescent girls and pregnant women.
Other highlights in the report:
-World population growth will continue. It is projected to rise to 9.3 billion by 2050 from 6.6 billion in 2007.
-Fertility rates may be rising again in some European countries where they have been on the wane. The number of children women are having is increasing in Italy, Spain and Sweden, among others.
-The prevalence of HIV/AIDS probably is lower than earlier estimated but remains an international crisis. More than 4 million people were newly infected in 2006.
-The international refugee population increased during 2006 to 9.9 million from 8.7 million. It attributed the increase in large part to Iraqis leaving for other countries, particularly to neighboring Syria and Jordan.