I don't mind talking about it here. I actually have a few threads on the subject, linked below.
It could be in part due to genetics, however I'm quite sure my lifestyle was the key culprit. When I got my driver's license at 17 (and subsequently stopped walking to get places), I started putting on weight. Compounding the problem was a horrible diet (high processed carb, high [bad] fat, etc.), and I lived a VERY inactive lifestyle. I mean, next to no activity. By the time I was in my early 20's, I had ballooned up to 255lbs, mid 30's bodyfat. I continued this way for the better part of 15 years which undoubtedly had a profound negative impact on my physique and metabolic processes.
http://forums.steroid.com/nutrition-...hlight=insulin
http://forums.steroid.com/nutrition-...hlight=insulin
http://forums.steroid.com/nutrition-...hlight=insulin