The Wealth of Nations by Part 1 Chapter 11 Page 129

else is the common and favourite vegetable food of the people, constitutes, in every civilised country, the principal part of the subsistence of the labourer. In consequence of the extension of agriculture, the land of every country produces a much greater quantity of vegetable than of animal food, and the labourer everywhere lives chiefly upon the wholesome food that is cheapest and most abundant.

Butcher’s meat, except in the most thriving countries, or where labour is most highly rewarded, makes but an insignificant part of his subsistence; poultry makes a still smaller part of it, and game no part of it. In France, and even in Scotland, where labour is somewhat better rewarded than in France, the labouring poor seldom eat butcher’s meat, except upon holidays, and other extraordinary occasions.