Great article at CNN on a fitness trainer who gained 70 pounds and lost it in one year.
The part that really jumped out at me was how fast someone can go from the pinnacle of fitness to about my (current) size:
He gave up the gym and started consuming junk food, fast food and soda. In just six months, he went from 193 pounds with a 34-inch waist to 265 pounds with a 48-inch waist.
Of course he wrote a book too.