User blog comment:The Bonehead Skipper/Unanswered Questions for the New World/@comment-4783583-20120204163811

my guess is that there is a  kind of special drink/brew that makes you grow bigger then you normally would, drinking this brew most likely comes with a price, (price in the sense of sacrifice) and has more effect on young people then it has on older people. My guess is that helmeppo and coby are both drinking this, the admirals all drank it, the karikiri destroyers drank it (by accident) and whitebeard drank it too.