A controversial study published earlier this year in the Journal of the American Medical Association shows that overweight people have significantly lower mortality risk than normal weight individuals, and slightly obese people have the same mortality risk as normal weight individuals.

This meta-analysis, headed by statistician Katherine Flegal, Ph.D., at the National Center for Health Statistics, looked at almost 100 studies that included 3 million people and over 270,000 deaths. They concluded that while overweight and slightly obese appears protective against early mortality, those with a body mass index (BMI) over 35 have a clear increase in risk of early death. The conclusions of this meta-analysis are consistent with other observations of lower mortality among overweight and moderately obese patients.
Many public health practitioners are concerned with the ways these findings are being presented to the public. Virginia Hughes in Nature explains “some public-health experts fear…that people could take that message as a general endorsement of weight gain.” Health practitioners are understandably in disagreement how best to translate these findings into policy, bringing up the utility of BMI in assessing risk in the first place.
Walter Willett, chair of the nutrition department at the Harvard School of Public Health, told National Public Radio that “this study is really a pile of rubbish, and no one should waste their time reading it.” He argues that weight and BMI remain only one measure of health risk, and that practitioners need to look at the individual’s habits and lifestyle taken as a whole.




