The concept of living standards is at the base of economics. Since Adam Smith's "The Wealth of Nations", several economists tackled questions such as what determines and how to improve the welfare of a society. The long-lasting debate on the effect of industrialization on the living standards has involved, and continues to involve, generations of economic historians. No agreement exists, however, on how to define welfare and therefore on how to appropriately quantify and compare it across countries or across time. This work analyses the relationship between the economy and the standard of living, meant in a broader sense, which goes above the traditional identification of welfare with material prosperity. More specifically, body size is used to analyze the effect of economic changes on the biological standard of living as well as the reverse link which goes from biological outcomes to economic performance.