The phrase is now standard in today’s public health parlance. Everyone from the National Institutes of Health, to the Centers for Disease Control and Prevention, to the nation’s largest health philanthropy, the Robert Wood Johnson Foundation, assert we need to aim for a healthy weight. In the case of children, for example, RWJF is supporting an entire line of discourse and research on how to “ensure that all children enter kindergarten at a healthy weight.”
But for all the emphasis we put on attaining a healthy weight (whether in public health, the fitness industry, or social norms), is this really where we should be focusing our attention? Do we understand the connection between health and weight all that much?
Unfortunately, not as much as it would seem from such decisive statements.
The so-called “obesity paradox” was back in the news the other day thanks to another study, this one in the Annals of Internal Medicine, that found people who were overweight, but not obese, lived longer than people who were normal weight or underweight. Researchers observed over 10,500 patients with type 2 diabetes over a 10-year period.
Such contradictory findings have led to a spirited debate among researchers. Some, like those from Harvard’s Department of Nutrition, have voiced pointed criticism about the integrity of past study’s methodologies.
But, the fact that the “obesity paradox” keeps coming up in nutrition and public health research suggests there might be something to it.
One place to start is by looking at risk factors for metabolic syndrome among normal weight individuals. This graph is based on data from CDC’s National Health Statistics Report from 2009, which looked at the prevalence of metabolic syndrome among adults over the age of 20 in the US from 2003 to 2006. So, if you look at both men and women, there is a sizable prevalence of different metabolic syndrome risk factors even though these people are “normal” weight. (Note: data were not available for the prevalence of normal weight men with abdominal obesity.) In particular, you’ll see more than 1 in 4 normal weight men and women have elevated blood pressure, and about 35% of normal weight men have high fasting glucose, a risk factors for developing type 2 diabetes.