Nature vs. Nurture
There is a misconception out there that lifestyle and food choices don't matter. Although many people seem to be OK eating junk food and abusing their bodies, and some people do struggle even with eating a healthy diet and the nine yards, that doesn't negate the fact that lifestyle matters. Think of it like a bank account. Some people are born with an account full of cash. Every time they mistreat their body they are so to speak taking a withdrawal. Due to the large balance they started off with, it will take a while till they get of overdrive. Others come with a low balance in their account, they have to be more careful with their habits. However everyone has their breaking point, where all the physical and emotional stress overburdens their body. At that point the body says enough, start depositing and not just withdrawing. The point is lifestyle choices matter. Think ahead-before the crash.