Why would bodybuilders know more about health and fitness than triathletes, tennis players, or powerlifters? They read a lot of sciencey-sounding material, but are they savvier consumers of information than the average dieter? The faddishness of bodybuilding routines and bodybuilding nutrition doesn't build much confidence, and the nature of bodybuilding competition doesn't test whether a body has any functional capacity. I'm not saying bodybuilders aren't fit, just that their hobby doesn't demonstrate their fitness the way a triathlon demonstrates that a triathlete has good endurance and cardiovascular capacity, or squatting a heavy weight demonstrates that a powerlifter is strong.

In general, my good sense rebels at the notion of connecting bodybuilding with health. Bodybuilding is the game of hacking one particular, and particularly superficial, way of judging health and fitness. That's fine and good -- anything that gives people fun and satisfaction is great -- but there are many other ways of judging health and fitness that seem prima facie far superior to an obsession with body fat and muscularity. And there are many people busy hacking those superior measures: triathletes, powerlifters, soccer players, boxers, wrestlers, tennis players, and so forth. You have to assume that nutritional knowledge in those sports is pretty far behind bodybuilding before you would assume that an ideal powerlifter's diet is as healthy as an ideal tennis player's diet.