John was once fit in his teens but went through a time
when he was out of shape and didn't eat properly.

My question is this. Do our bodies have a memory of being fit (even if it was years ago) and can rebuild muscle faster than a guy who never had muscle tone at any point in his/her life?

I hope not cause I never have been in super shape - just thin and soft.

I believe it's easier to get back into shape after years of neglect than to get into shape the very first time. It could be that the type of person who was never fit to begin with didn't have the genetic advantages of someone who was athletic at one time.

But people who have never been fit seem to get the most out of the improvements since it can make a dramatic impact on their lives. Like in The Nutty Professor when he's skinny for the first time and he goes crazy buying spandex.