Projecting the future of U.S. health and longevity.

Is the health of the U.S. population improving or getting worse, and how are health and medical costs influenced by obesity? How will anticipated advances in the biomedical sciences influence life expectancy and the cost of health care? The paper by Dana Goldman and colleagues is a daring speculation on the life-extending effects of possible future technologies--a valuable exercise given the speed of technological advances. Darius Lakdawalla and colleagues provide a methodologically solid basis for concluding that not only does obesity kill, it also takes an alarming toll on health and health care spending at levels that require immediate intervention.