So I'm a relatively young guy, and pretty fit due to lots of cycling and keeping active. However, every time I look around where I live (New York City) and where I've worked, I see that many full-fledged adults who were active in their younger years have had other things to worry about (marriage, pregnancy, real life problems, etc), and their health has been the first to get hit hard. It's very common, if not average, to see adult men overweight or worse.
That makes me really worried. Has anyone had those fears when they were younger, and what steps were taken to avoid going down that path? I know it really sounds like a dumb question, but this is actually one of my biggest concerns.