Exploring the returns to scale in food preparation: Baking penny buns at home

We show that as household size increases, households substitute away from prepared foods and towards ingredients. They also devote more time to food preparation. These observations (1) are consistent with a simple model with home production, returns to scale in the time input to food preparation, and varieties of food that differ in the required time input; (2) support the idea that returns to scale in home production are an important source of returns to scale in consumption; and (3), mean that across household sizes, household market expenditures on food are not proportional to food consumption quantities. The latter may provide a partial explanation for a puzzle raised by Deaton and Paxson.