Well, just about a year and a half ago I was 280lbs, and a sloth in every way, shape, and form.
Being 6'8" and overweight was hell on my body, I couldn't stand long, since blood would pool in my legs and cause pain.
I decided I needed a change. Started eating better, and lost 15lbs. Visited a LBS a month after I started dieting, and was told I was SOL on a bike that fit. But, they'd do their best. Came home with a new bike that day, road about 1/2 a mile and had to give up.
Now I'm at 220lbs, just about ideal for me, maybe a few pounds heavier than "normal" but I've got a large frame.
To be honest I never road a LOT, one or two 20-30 mile trips a week, with commuting and short family rides the rest of the time. Diet got me where I am more than anything.
I've gone car free since then, and do anything that needs done via bike or taxi if needed.
I'm currently going through one of the tougher times in my life, so I felt inclined to cheer myself up by congratulating myself.
Next goal? Quit smoking and do a cross country tour this year. Weight loss is a breeze compared to kicking nicotine though.