By now we’ve all heard it so often we can almost say it in our sleep: Two thirds of Americans are either overweight or obese, using the standard cutpoints based on Body Mass Index (a measure of weight corrected for height), with a BMI of 25-29.9 being defined as “overweight” and a BMI of 30 or more as “obese.” This is a serious public health problem, right?
Yes, it is well-documented that obesity is detrimental to health. It leads to diabetes and hypertension; it makes exercise difficult and unpleasant (and thus undercuts the benefits that exercise confers). Roughly one third of US adults are obese and that is a problem.
BUT unless it’s a way-station on the road to obesity, then being “overweight” is not a public health problem. It is not an individual health problem. It is not a health problem at all.
In fact, carrying a little extra weight as a buffer against disease and starvation may even have some protective effect. In 2005, and in a followup meta-analysis in 2013, Katherine Flegel, an epidemiologist the US Centers for Disease Control and Prevention, touched off a firestorm by presenting data suggesting that "overweight" adults have lower mortality rates than so-called "normal weight" individuals - the so-called "obesity paradox" - a controversial finding for which she has been roundly criticized but that has not been conclusively disproved.
And yet the one third or so of Americans who fall into this weight distribution have been persuaded that they have a serious health problem that needs to be addressed. Here's the thing: Using “overweight” to refer to BMI 25-29.9 is dishonest and misleading, suggesting as it does that something is wrong, and the term should be stricken from our vocabularies. Yes, I’m a little overwrought on this topic, and here’s why:
1) The term is inaccurate both from a statistical point of view (in fact, the BMI of the average American now falls into this category) and from a health point of view.
2) The term is accurate from a cosmetic point of view only to the extent that we have allowed the judgmental terminology to infect our perceptions. It is a formula for stigmatizing what doesn’t deserve to be stigmatized, for making people, and especially women, feel unhappy about something that should not be a cause for unhappiness. I have no problem with creating standard categories using arbitrary cutpoints for research purposes, but giving these categories tendentious names is something else altogether. (Note that the government is now referring to what used to be labeled "normal weight" as "healthy weight" - solving the problem that BMI<25 is no longer normal but creating a new one by suggesting that BMI>25 is somehow not healthy. The words we use matter!)
And lest you think I’ve forgotten the topic of this blog:
3) It has been repeatedly shown, in my own research and that of others, that smoking is used as a dieting tool, especially by women, and that fear of weight gain deters many women from quitting. Most smokers gain a few pounds when they discontinue tobacco use, and yet 40% of women smokers state that they are not willing to quit if it means gaining a single ounce. Quitting smoking is hard enough without adding the threat of creeping into this stigmatized bracket. And while becoming obese is not desirable, postcessation weight gain in amounts that would offset the health benefits of quitting is unlikely except among "super-gainers" - individuals who may need extra help in managing excessive eating behaviors that they may have held at bay by smoking.
4) Obesity - and in particular, extreme obesity - is a serious public health problem and one that needs attention. That said, it is dishonest to use the “two thirds of Americans are either overweight or obese” mantra to justify the devotion (and in a climate of scarcity, the diversion) of resources to addressing this problem. Based on the arbitrary cutpoints in common use by both researchers and journalists, the most nearly correct statement about the magnitude of the public health problem posed by excessive weight is that nearly one-third of Americans are obese. Period.