Why? I'm 3-4 stone overweight and I can piss over a 22 mile bike ride. Managed 45 miles a day, every day for a week last year - with 15kg of camping gear on the back. Will you have the brakes on the whole way, or something?
well im about 8 stone over weight, and I will be carrying a few items as well. ive not ridden regularly for a few years now, and have been setting myself distance challenges, the last one I did was 12 miles, which I handled ok, this one is 22 miles, 11 miles there & back.
Just don't cycle fast. Cycling actually burns less cals than walking unless you consistently maintain high speeds. Keep it at around 10mph average and you shouldn't have any trouble at all, just take the odd few minutes here and there to stretch your legs and drink some water. Take some sports bars if need be.
I did make it back, didn't go that fast however, the first 11 miles I did in about 90 minutes, the 2nd I got lost and ended up about 1 hour & 50 minutes. I wont be doing it again till im a little bit fitter.