Pradeep S. Mehta, secretary general of the center for international trade, economics and the environment of CUTS International, an independent research institute based here, said that if Americans slimmed down to the weight of middle-class Indians, “many hungry people in sub-Saharan Africa would find food on their plates.”

The United States uses — or throws away — 3,770 calories a person each day, according to data from the United Nations Food and Agriculture Organization collected in 2001-3, compared with 2,440 calories per person in India. Americans are also the largest per capita consumers in any major economy of the most energy-intensive common food source, beef, the Agriculture Department says.

And the United States and Canada lead the world in oil consumption per person, according to the Energy Information Administration, an Energy Department agency.