The price of one sweet calorie (with Veronika Dolar)

We propose a new method to measure food prices that adjusts for changes in calories consumed over time. Using household expenditures share data for different food categories, we calculate the price per calorie as household expenditures divided by calories. We illustrate the impact of changes in per-calorie food prices on people's eating decisions and weight with two examples. First, we look at the increased popularity in dining out. Using basic economic theory of supply and demand, we show that changes in per calorie food prices can potentially explain the increase in total calories consumed away from home, while changes in simple food prices cannot. Second, we analyze the impact of the relative price of high- versus low-nutrient-dense food on the average body-mass index. We find that changes in per calorie food prices account for a greater fraction of changes on BMI compared with simple food prices.