Food preferences, naturally, are primarily based upon levels of hunger. The law of supply and demand is not a new idea. It is likely that food preference and availability has been a major force in driving the evolution of humanity. Consider the different ecosystems in which people have existed. Given the enormous variability, it is surprising there are not more metabolic differences between human racial groups.
All species seem driven to maximise return for food gathering effort.
Therefore, especially when times are tough, we eat what we can get. In some species, notably among the weasel family, dimorphism between males and females is believed to have been sustained by different food preferences and the need for the female to be smaller than the male to ensure she doesn't kill him during mating. Because he's bigger, he can kill bigger prey which ensures he doesn't impose upon her food supply and vice versa, and at the same time, it ensures he eats bigger meals to remain physically larger. Whilst stereotyping is dangerous, it is clear that certain groups of people have taboos about certain foods, styles of clothing and social rules about dealing with others in their own communities. These, like anatomical and physiological features of individuals, have evolved to reach their present state.