The recent hysteria over "obesity," whatever that is, dovetails perfectly with our society's preoccupation with thinness as virtue. It has nothing whatever to do with concern for health:
Of course, one reason the Harvard claims are treated with such respect is that they tell people what they want to hear. Their claims dovetail perfectly with social prejudices that declare one can never be too rich or too thin, and with the widespread desire to believe that sickness and death can be avoided if one follows the rules laid down by the appropriate authority figures. Combine these factors with the social cachet wielded by the Harvard name, a willingness to make brazen assertions that run from serious exaggerations to outright lies, and lazy journalism of the "some say the Earth is flat; others claim it's round; the truth no doubt lies somewhere in the middle" type, of which the Scientific American article is only the most recent example, and you have a recipe for an epidemic of wildly misleading statements dressed up in the guise of authoritative scientific discourse.
