A new report from the United Nations says that one way to prevent obesity in the future is to cut malnutrition now in pregnant women and children.

The report, from the U.N.'s Food and Agricultural Organization (FAO), finds that hunger during pregnancy programs fetal tissue to get the most out of the scarce food energy available. That leads to over-nourishment later in life when food is more plentiful. When coupled with a sedentary lifestyle, that leads to obesity.

The FAO finds the problem especially acute in developing countries, where food is becoming more cheap and available. These nations cannot cope with the health costs of treating obesity and the chronic diseases it causes, such as diabetes.

"These ongoing changes in nutrition mean that a growing number of developing countries face the 'double burden' of under- and over-nutrition and their associated economic and health-care costs," the FAO says in a statement.