if you notice you gave the distinction between fat and thin white women but put all black men into one category,i will tend to think by black men,you meant African- America which i am not
In my opinion,your generalizations are not accurate.preference and taste play a role in mating,some will like fat,some will like slim,normal or chubby,it all depends on the what he wants and thinks suit his sexual needs
In Nigeria,Most men will prefer fat ass,i meant girls with a normal and big buttocks(not obese) because to them that is their sexual needs and all the women they have known from their mom to girl-friends have a big buttocks which naturally is the anatomy of black women.
in my country, we stereotypical say white women do not have ass so they are not sexy, before most of our men wont go for white women because they dont have what they want but the recent generation of white women are having big ass,so you see more black men into the one with ass than the one without.
But i never see any Nigerian that says he wants an obese woman except that is his sexual preference.