Counterpoint: we have NOT failed as a species Humans are animals with base instincts.  But some of us are so smart, we have figured out how to exploit weaknesses of others for profit (gastric bypass, gastric balloons, etc).  Moreover, some of us live in environments with temptations that others succumb to and yet we use our human capabilities to resist. Fat people have difficulty reproducing and the worse the obesity epidemic gets, the more it'll affect reproduction.  This is just expedited evolution.