I was BMI 39.8 about june last year, down to 30 now. Though i've always had a decent amount of muscle and a very stocky frame. But uni, depression, drinking, awful halls which mostly meant eating out meant i put on about 4 stone during uni and wasn't slim to start with.
Mostly, like the guy who rowed and ate silly amounts, I used to do school, work and ride my mountain bike or play footie for pretty much two hours every day, weekends sometimes half a day of just pure exercise. When my knee's went out I was eating like a hugely exercising growth spurt teenager does, i put on so much weight before I got back to eating like a non exercising person and my growth spurt pretty much stopped the same time.
Oh well, at least I'm finally getting it sorted.