I admire anyone who can do a century on a couple of peanut butter sandwiches and a banana but I ain't one of them and you may not be either. If you are currently doing 53 mile rides you are close, you want to work in a couple/three 65 through 80 mile rides prior to the century. While you are doing that pay attention to how you feel. If you take along some light snacks and finish low on energy then you probably either will have to supplement what the ride gives you to eat at rest stops or else plan on eating a lot of it. I've done two typical centuries with typical bike club rest stop food offerings and I ran out of energy at about 80 miles on both of them. Earlier this year I did a 75 mile loop on a local century, pigged out on the rest stop food and felt fine. And just last week I did my fourth century during RAGBRAI, finishing as strong as I did on the other three. RAGBRAI is a 400 mile long banquet, you can eat as much as you want pretty much as often as you want and that is what works for me! But if you can do it on a couple of sandwiches, more power to you!!