Price Index (CPI) using weights that reflect the nutrition value of food items, as opposed to ones that reflect spending on food items.

First, when considering a nutritious diet, we find that the cost of food might be more prohibitive than other calculations suggest. CoRD per individual per day totaled SL Rs 187 in Sri Lanka ($2.05 in 2011 $PPP), Prs 87 in Pakistan ($1.43 in 2011 $PPP), and Af 45 in Afghanistan.<sup>5,6</sup> Compared to the (calorie-based) food component of the poverty line, a CoRD-calculated diet cost 38 percent more in Sri Lanka and 15 percent more in Afghanistan. Using an alternative lower estimate of CoRD, we infer that 49 percent of individuals in Sri Lanka and 58 percent of individuals in Pakistan spend less on food than CoRD requires, suggesting that many might be unable to afford a recommended diet. Second, we find that variability in CoRD across cities (or districts) in a given country is driven more by variability in the price of vegetables and dairy than by variability in the price of other food groups. Local vegetable and dairy prices are more likely subject to local productivity trends as such products are perishable and difficult to transport. Third, a comparison of the NPI and the food CPI indicates that the price of a nutritious food basket is much more seasonal than the price of a typical food basket in India, Pakistan, and Afghanistan, but not in Sri Lanka. Fourth, in India and Pakistan, the price of a nutritious food basket has been increasing over the years in comparison with the price of a typical food basket. This sensitivity to seasonal factors and faster rising costs is largely due to fluctuations in the price of vegetables.

Nutritious diets must be affordable for the average citizen if policymakers are to effectively tackle malnutrition in South Asia. However, policy options are constrained by a lack of knowledge about where and when the cost of nutritious diets is high, where it is increasing, and which food groups are particularly unaffordable. We emphasize that largely due to the price of nutrient-rich, perishable foods, the cost of a recommended diet can be prohibitive and the cost of a nutritious food basket is rising faster than a typical basket in certain countries. At the same time, we offer accessible methods for policymakers to track price trends for nutritious foods by harnessing existing food cost data, and thereby make more informed policy decisions.

The remainder of this paper is organized as follows. In Section 2, we compare our methods to other measures to estimate the cost of nutritious food. We detail our methods in Section 3 and present results in Section 4. In Section 5, we present alternative calculations of CoRD using data from household surveys. We conclude in Section 6.

# **2 Other measures of the cost of nutritious diets**

This paper contributes to and complements emerging work on the cost of nutritious diets. The aggregation of food price data into the food CPI can be a misleading indicator of the cost of nutritious diets, because expenditures are not necessarily related to nutrition needs. Therefore, a relatively crude but important first step has been to _disaggregate_ the underlying price data for the CPI by looking at the prices of various food items separately. For example, using internationally comparable prices across 177 countries from the International Comparison Program (ICP),<sup>7</sup>

> 5 Purchasing power parity (PPP) conversion factor is unavailable for Afghanistan. The data for Sri Lanka are from December 2017, for Pakistan from June 2017, and for Afghanistan from September 2017. Due to the different months being used, caution is advised in comparing calculations across countries.

> 6All dollar figures are in US dollars unless otherwise stated.

> 7 http://www.worldbank.org/en/programs/icp.

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