Your diet is hideous. Please have a look at someone like Coldo's thread where he lists the diet he used to reduce his weight drastically before he started to bend bars in the gym by deadlifting like a mad cunt.
Personally speaking, I've found that swimming is a fantastic start... don't worry if you are self-conscious, if you are, then I know you'll assume that everyone is looking at you, but they aren't bothered and they won't see you when you're in the water anyway.
I also do a set of plank and sit-up/crunch exercises when I get up and before I go to bed daily. They aren't easy, but I've seen an improvement in the time of the plank and the number of sit ups that I can do so I'm happy that it's moving in the correct direction.
Riding a bike won't be an issue I don't think, I was probably there or there abouts weight wise when I bought my new bike.. and it's held up alright on the road, tracks, downhill runs etc.
Cheers,
Grant