Fatness, Mortality, and the Concept of Truth

Is being overweight a risk factor for mortality? Or a protective factor?

Posted Jan 03, 2013

As the holiday season nears to a close, like many people I have been gearing up to return to some self-discipline and shed the extra pounds that were accumulated over these past six weeks of indulgence. Indeed, I have been sharing with my family my belief that we all need to change our ways and eat “healthier”. Although none of us are obese, we are all vulnerable to being overweight and we all know that being overweight is associated with serious health risks. Or is it?

A fascinating study was just released in the Journal of the American Medical Association that did a sophisticated meta-analysis of the relationship between weight and mortality. The study combined the results from 97 studies resulting in a sample size of almost 3 million individuals and 270,000 deaths.

The results? Overweight individuals (individuals who have a body mass index between 25 and 30) were significantly LESS likely to die than normal weight individuals. Even individuals who were mildly obese demonstrated a significantly lower mortality rate than normal rate individuals. It was only for individuals who were moderately to severely obese that the mortality rate shot up rather dramatically.

While conclusions about causation cannot be drawn (i.e., we should not all run out and put on pounds), and there are other studies that have found mortality risks associated with being overweight, the conclusion can be made that the relationship is complicated and certainly not strong and direct—if there were a strong and direct relationship, the study would have found it easily. (See here for a more detailed analysis of what the results might mean).

Prior to today, I thought it was pretty well-known being overweight was a mortality risk factor. But in reality, the data are very mixed, and certainly do not offer strong support for this claim. So where does the “knowledge” about the mortality risks of being overweight come from? Paul Campos, who has an Op-Ed piece in the NY Times on this topic, writes:

“How did we get into this absurd situation? That is a long and complex story. Over the past century, Americans have become increasingly obsessed with the supposed desirability of thinness, as thinness has become both a marker for upper-class status and a reflection of beauty ideals that bring a kind of privilege…Anyone familiar with history will not be surprised to learn that “facts” have been enlisted before to confirm the legitimacy of a cultural obsession and to advance the economic interests of those who profit from that obsession.”

With a minimal amount of self-reflection, there is little doubt that although I justify it in terms of being healthy, my desire for me and my family to be trim and fit is closely tied to vanity and cultural judgments and norms of physical attractiveness.

Perhaps the most significant thing this article got me reflecting on is the concept of the truth, and served as a powerful reminder that the things we know and the things we justify to others are so often a product of our own wishful thinking or the cultural Zeitgeist in which we are immersed.