Once considered a great danger to health and mortality, smoking will likely pale in comparison to the threat of obesity, according to an article published in The New England Journal of Medicine (2009; 361 [23], 2252–60). The article suggests that, if the current obesity trend continues, its disadvantages will “increasingly outweigh the positive effects gained from declining smoking rates.”

The University of Michigan Health System and Harvard University study forecasted life expectancy from 2005 through 2020, assuming a continued reduction in smoking rates. Trends in body mass index (BMI) were also considered. “The negative effects of increasing BMI overwhelmed the positive effects of declines in smoking in multiple scenarios,” stated the study authors. “In the past 15 years smoking rates have declined by 20%, but obesity rates have increased by 48%. If past trends continue, nearly half of the population—45%—is projected to be
obese by 2020.” The authors also suggested that if all U.S. adults became
normal-weight nonsmokers, life expectancy could increase by 3.76 years.