Should We Expect Less of Our Longevity?

One of the main topics of Tom Freidman's, Hot, Flat and Crowded, is overpopulation. He discusses in his book the major effects that overpopulation has on the world. Not only is it a problem now, but it is going to be a problem for our future unless we do something about it.
How exactly do we go about decreasing our population size? Or how do we prevent it from increasing at the rate it is growing now? Is it ethical to stop improving our health care and simply ignore the needs of individuals in order for them to live? I was interested to find an article that stated the statistics of longevity of men and women in New York and in the entire nation. By the end of the article the author, Roni Caryn Rabin, explained that the there is a gap in longevity between men and women. According to the directer of epidemiology, Carolyn Olson,

“We want to encourage New Yorkers to incorporate physical activity into their routines, pay attention to their weight and make small changes in diet, like eating more fruits and vegetables, consuming less sodium, and drinking more water instead of soda,” Ms. Olson said. “We want to send a message: we would like our men to be living longer.” 

It was reported that in the US females tend to live to the age of 82 and men only to 76. Although the average person prefers to have a decently long life span, should our expectations decrease in order to help the issue of overpopulation?