For many Americans, the New Year is often a time to look back on both the successes and failures of the past. More importantly, it is also a time to look forward and to think about the changes we want or need to make in order to live happier and healthier lives.
Given that two-thirds of Americans are now classified as overweight or obese, is it any wonder that the top resolution for 2013 (and for 2012, and 2011, and 2010) is to lose weight. For most of us, this means eating less and exercising more. For some, this is a much more radical undertaking that can involve rather invasive procedures like gastric bypass surgery or (in the near future) the use of an AspireAssist: a mechanical pump that actually drains the stomach contents through a hole inserted through the abdominal wall.
We are a nation of fat people, and every year we resolve to do something about it. I’m no different. Despite the best of intentions last January, I left 2012 about five (well, maybe ten) pounds heavier than when I entered. I’ve again resolved to do something about it, and am two weeks into a dietary program that involves a rather brutal but effective herbal cleanse.
Our desire to lose weight is driven in part by media images of what healthy men and women are supposed to look like, namely the muscle-bound hunks and reed-thin waifs that appear in magazine and television ads. The multi-billion dollar weight-loss industry pushes a similar message of thinness. Finally, we are told time and time again by the medical establishment that it is dangerous to be fat.
For decades now, doctors and public health experts have been warning that those of us who carry a few extra pounds are likely to die at a younger age than our fit and trim counterparts. But is that actually the case? A new study published in a recent issue of the Journal of the American Medical Association suggests otherwise.
That widely publicized study, released just in time for our annual migration to the gym, reviewed data from nearly a hundred previously published epidemiological studies looking at the relationship between weight and mortality risk. Surprisingly, these data — collected from almost three million study participants in twelve different countries — suggest the exact opposite of what we’ve always been told.
It turns out that people who would be classified as overweight by current standards actually had a 6% lower risk of death than those who would be considered to be a normal healthy weight. For the average 5’10” American male, it is better to tip the scales at a weighty 220 pounds than at a slender 160 pounds, at least as far as the Grim Reaper is concerned.
This is good news for all us chunky monkeys, right? Well, we probably shouldn’t count (and deep fry) our chickens before they are hatched. These study results shouldn’t be seen as giving us license to spend our Sunday evening eating a pint of Häagen-Dazs while watching The Biggest Loser.
First and foremost, these data, like all epidemiological data, apply to populations not individuals. Overweight men and women were slightly less likely than normal weight men and women to die as a whole, but these data cannot be used to predict when you or I as individuals might die. Nor can they predict whether or not our deaths will be caused by obesity-related illness or by stepping in front of a bus.
There are also a number of scientific explanations for why these data fly in the face of conventional wisdom, as outlined in the editorial that accompanied the published study. Overweight and obese people might receive more medical attention and intervention; a number of studies have shown that physicians are more likely to screen and treat overweight patients for a variety of diseases.
The data may also be biased. When researchers looked at rates of death within the normal weight category only, for example, they found that those in the ‘thinner’ half of this category had higher rates of mortality than those in the ‘fatter’ half. The reasons why these thinner people had higher rates of death are unclear. Some may have been that thin because they were suffering from other underlying illnesses, like cancer or diabetes. Some may have suffering from eating disorders. The study did not control for these possibilities, and so the data may have been skewed.
A more plausible explanation for these findings, however, is that the medical and research community still have poor ways of measuring whether or not a person is overweight. The most commonly used measure of obesity is the body-mass index (BMI), which is the ratio of a person’s height to weight. Men with a BMI of 19-24 are consider to be normal, while those with a BMI of 25 or higher are overweight and those with a BMI of 30 of greater are considered obese. For the average 5’10” American male, this means you are overweight if you weight 175 pounds or more. But this crude measure doesn’t distinguish between fat and muscle, so relatively fit individuals who hit the gym regularly would be considered overweight by this measure even if they had six-pack abs. Inclusion of these individuals in the study might have skewed the data as well.
What this study tells us is not that it is okay to be fat but, rather, that we still have a poor understanding of what it means to be healthy. We need to move beyond the knee jerk ‘fat is bad’ mentality and focus on a ‘fitness is good’ approach. Current categories like thin, fat and obese make no sense. Fitness means different things for different people, and a somewhat overweight individual (at least as determined by our current crude methods) might be extremely fit and healthy while a relatively thin individual might be extremely ill and unhealthy. We need to focus not on what the scale tells us, but rather on having a healthy lifestyle that includes regular activity and eating right.
[This blog entry was originally presented as an oral commentary on Northeast Public Radio on January 10, 2013. It is also available on the WAMC website.]