According to a study published this week in the American Journal of Preventative Medicine, 33 percent of Americans are currently obese and as many as 42 percent could be by 2030. That's a substantial increase, but the conclusion that has captured everyone's attention is the explosion in health care costs that could accompany this increase in obesity, an estimated $550 billion.
Predicting how many Americans will be obese 18 years from today is a difficult feat because there are so many variables involved, as the researchers admit. But assuming that these estimates of obesity and its associated costs are accurate, they still don't tell the whole story. Body weight isn't all that matters when it comes to health, and it shouldn't be our primary focus when it comes to managing growing health care costs.
However many times the media claim otherwise, the fact remains that a big waistline isn't synonymous with poor health. As the authors of the current study point out, there is a relationship between "excess weight, poor health, and high medical expenditures," but that's doesn't mean obesity is the cause of the latter two.
Multiple studies have demonstrated that overweight people can be perfectly healthy if they eat well and exercise, but those behaviors won't necessarily make them any slimmer. Conversely, a poor diet and lack of exercise don't necessarily make people fat. This is a paradox for which we have genetics to thank, one inevitably overlooked by any attempt to link obesity to poor health and rising health care costs. At best, such an analysis blames one of the common symptoms of a poor lifestyle rather than the lifestyle itself.
This is evidenced by the fact that thin people are often plagued by the same medical conditions typically blamed on obesity. Lean children of type 2 diabetics, for example, are more likely to be insulin-resistant than lean children of non-diabetic parents, according to a study published in the New England Journal of Medicine. And since these individuals aren't obese, the insulin resistance is clearly independent of body weight.
Additionally, nearly 30% of adults in the industrialized world suffer from non-alcoholic fatty liver disease (NAFLD), which is often a precursor to type 2 diabetes and metabolic syndrome. The condition appears to impact both obese and normal weight individuals, too. According to a 2008 study, "Both lean and obese insulin resistant individuals have an excess of fat in the liver which is not attributable to alcohol or other known causes of liver disease ... Liver fat is highly significantly and linearly correlated with all components of the metabolic syndrome independent of obesity."
Also inescapable during any discussion about the costs of health care is the likely possibility that the healthiest individuals among us put the most pressure on the health care system. Compared to the obese and smokers, healthy people live longer and require more health care as a result. It's a controversial point, indeed one that seems counter-intuitive, but it finds ample support in the peer reviewed literature.
A 2008 PLoS Medicine study concluded that obesity prevention "... is not a cure for increasing health expenditures."A study published in the British Medical Journal found that preventive care tends to increase health care costs for the same reason, "... because of the medical expenses during added life years." A 2009 study conducted by Vanderbilt University economist Kip Viscusi also found that thin people who don't smoke, and thus live longer, are most responsible for rising health care costs.
So while we may see an increase in obesity and its associated health care costs in the coming years, it's important to remember that this is not the full story of the relationship between public health and obesity. Helping people address their weight problems and reforming the health care system are important issues and they deserve attention. But if we overemphasize the costs obesity, we risk doing more harm than good to public health.