Oh YA, it most definitely will catch up one way or another...I use to always be thin, never had to work at it, I could eat what I wanted and as much as I wanted (which I surely did) and never gain an ounce let alone a pound...now I have to work at it, it caught up with me, even having crohns doesn't keep me in shape amazingly with all the yrs of "running" to the can...but I'm glad I exercise regularly, I had no idea the many other benefits from it there are (mentally and emotionally) and so much more.
Not to mention, I ate a ton of junk, a sugar junky if you will, and quite obviously that plays it's own role with health (not just weight)...I know many people still get crohns that have never or hardly ever touched junk food but hey, they havn't figured out all the triggers yet and we all know that CD is strongly linked to bacteria and sugar (along with processed foods) has it's link to bad bacteria.
It's so true that "you are what you eat"...(I learned that the hard way).
My bum is broken....there's a big crack down the middle of it! LOL :)