In traditional Britain the choice of foodstuffs was severely limited. Most people ate only what their local area produced, and even then, they largely confined themselves to what it could produce most easily and abundantly. The volume of the crop was more important than its quality, for they lived for much of their lives on the edge of starvation. It was cereal crops which, under conditions prevailing in traditional societies, yielded most abundantly and most reliably, and it was on the breadgrains that most people depended for the greater part of their food supply.

The factors governing diet, that is the variety and the relative abundance of foodstuffs, were many. Among them the local soil and terrain were of foremost importance. Without anything beyond an empirical knowledge of agronomy and soil science, people had learned to adapt their cropping systems as far as was practicable to local conditions.