Professional athletes seemingly hit the piss more than you think. You would too if your job entitled only a few hours of work a day. Beckham is a pretty good model for an elite athlete, mid 30s, still commands a role in one of the world's best national teams albeit outside starting 11. And don't models party super hard? I would imagine that a combination of good genetics and sometimes unhealthy practices get models to where they need to be in terms of body shape.