Highlights

• Addressing poor diet quality is emerging as an important development policy priority.

• Our Reference Diet Deprivation (ReDD) index is a quantifiable measure of diet quality.

• ReDD accounts for diet costs and consumption gaps across multiple food groups.

• Model simulations show ReDD is sensitive to changes in incomes and relative prices.

• The pattern of agricultural growth is shown to matter for dietary outcomes in Nigeria.

Abstract

Improving diet quality is an emerging development policy priority. Existing indicators emphasize the cost and affordability of healthy diets but have not attempted to measure how far households are from ideal diets or how policies may nudge them closer to them. We propose a new Reference Diet Deprivation (ReDD) index, estimated from household consumption survey data, that measures the incidence, breadth, and depth of diet deprivation across multiple food groups. While informative as a standalone measure, we demonstrate how the ReDD index can be integrated into an economic model to examine changes in diet quality under different policy or external shocks. Our Nigerian case study shows that productivity growth in the dairy, pulse & nut, fruit, and red meat value chains have more potential than staple crops to reduce diet deprivation. While these findings have implications for food and agricultural policy prioritization in Nigeria, the study more importantly demonstrates the usefulness of the ReDD index for assessing diet quality and examining the drivers of dietary change when used in conjunction with a simulation model.