I would venture to say it's a compromise of nature and nurture.

On the nature side we find that we have evolved with our genes and our tastes so that in colder northern Climes such as we are in we will tend to favor fatty foods that would allow us to weather harsher winters etc. with women men are more inclined to favour women with child-bearing hips and with an athletic body and large breasts so that the women will be able to reproduce and care for offspring.

Then on the nurture side, and I personally think this attributes more for women, we are given certain foods as children, we are exposed to foods and women by the media which cause us to favour other less native foods and women. Thus why we might prefer a more tanned girls due to FHM etc. or deep fried foods.

Just my two-penneth from what I've read and experienced...