I should hasten to point out to everyone that cup size is relative to bra size (as in the size around the body). Eg A 22D is equivelant to 20DD and 18 E etc.
I am currently wearing a 22D but that is because I am deceptively broad around my body. Fortunately I don't look it.

I remember one lady fitting me for a bra many years ago shaking her head in disbelief when she took all the measurements and determined my bra size - she thought she made a mistake the first time and redid them. Even if I lost all the weight I need to loose, I will never be smaller than an 18/20 sizing. I don't carry much weight on my top half as it is and I am still 22D interestingly, my clothes size is 18.
Mame