Art Caplan editorializes on the death of SF 49ers lineman Thomas Herrion. Although Caplan admits that “I have no idea what caused this tragic death”, he notes that Herrion weighed 310 pounds at 6′3″ - and that over 300 (!) other professional football players top the scales above 300 pounds. (Caplan also notes that the rise of extreme obesity in the NFL mirrors that in general society: 20 years ago, only 5 NFL players weighed this much.) Caplan assumes that weight is implicated in Herrion’s death and that it is a health problem for the other players as well.

[N]o medical or insurance table would give any indication that weighing 300 pounds or more is healthy for anyone. It is estimated that more than a quarter of all NFL players are morbidly obese, according to the Journal of the American Medical Association.

He has a suggestion, as well:

The only reason for this explosion in weight is the need to keep up with the competition. Set a limit on weight and few players or coaches would probably complain.

The NFL has made a huge effort to get a handle on the problem of performance-enhancing drugs. Drug testing is becoming increasingly common and the use of steroids and other substances is on the decline. But the NFL, as the country’s most popular and prominent pro league, has a bigger problem on its hands: obesity. It is time for pro football to convene a panel of experts, trainers, coaches and players and come up with some strict guidelines on weight and body mass.

The intuitive appeal of his argument is obvious, but it rests on a very slim (no pun) foundation.

Caplan is probably right that many NFL players rank as “morbidly obese” by the BMI standards commonly used - but those standards implicitly assume an average non-fat body composition for each given height. Thus, anyone of a particular height who exceeds a particular weight will be evaluated as obese, on the assumption that the “excess” weight must be all fat - no matter what their actual body composition may be. The BMI (what I assume Caplan means by “body mass”) does not correct for high or low muscle mass. Bodybuilders and other heavily-muscled individuals will routinely rank in the overweight or obese categories even though carrying extra muscle is not nearly as unhealthy as carrying lots of fat.

NFL players follow punishing weight-lifting and physical training regimens (often enhanced by steroids - which Caplan explicitly ranks as a smaller health problem than the bulk they produce). Although they do not always have the chiseled muscle definition of bodybuilders (as most true athletes do not), they are extremely muscular and probably few have the kind of body-fat percentage that the average sedentary “obese” person does. It is not clear that simply being heavy by itself is a health hazard, especially for extremely fit and active athletes - at the very least, it is certainly true that being “obese” by the BMI standard is a very different phenomenon for them than for the average non-active person. I suspect that there is actually little research on the health hazards of high muscle-based body weight for persons with low or normal body-fat percentages.

Caplan seems to have extrapolated from a standard scale to the situations of very much non-standard individuals. To promote a general policy of absolute weight limits without regard to body composition is both a broad-brush solution to a more complicated problem, and a focus on, very likely, the wrong issue. It might make more sense to impose body-fat-percentage limits, to ensure that players maintained a healthy body composition no matter what their size and weight - but, given the demanding training schedules the players keep, a body-fat limit might not wind up excluding anybody other than the coaches. If so - if this herd of 300-pounders coursing down the NFL’s gridirons is really composed of uniformly muscular, moderately-fatted, generally healthy players - then there is likely nothing to worry about in the first place. Caplan ought at least to look into this question before applying the couch-potato standard to professional athletes.

Hat tip: AJOB/Bioethics.net