calorie-price ratios show that the prices for healthy food categories are higher than those for unhealthy food categories (Headey 2017).<sup>8</sup> Our methods, as well as other measures, consider _reaggregating_ food price data to account for nutrition. One method reaggregates data to show an index of the cost of minimum dietary diversity, following the minimum dietary diversity score for women (MDD-W) (Masters et al. 2018). Several others calculate the cost of achieving nutrient adequacy (Deptford, Allieri, Childs, and Damu 2017; Cofer, Grossman, and Clark 1962; Masters et al. 2018). A prominent methodology among the latter is the Cost of the Diet (CoD), developed by Save the Children UK _._ CoD is a linear programming tool which uses available food price data, and models the cost of a theoretical, simulated diet (food basket) that satisfies nutrient requirements of a household at the minimal cost, based on the availability, price, nutrient content, and acceptability of local foods (Deptford, Allieri, Childs, and Damu 2017).<sup>9</sup> CoD has been calculated in various countries in South Asia. CoD tends to be higher than the cost of an energy only diet; it is also higher in certain seasons and varies across geographic location.<sup>10</sup> Our calculations of CoRD and NPI build on the methodologies described above, with a few important differences. While <mark>Cost of the Diet b</mark> ases its calculations on meeting essential vitamins and minerals, CoRD reaggregates food price information based on food-based dietary guidelines. Such guidelines are a representation of diets that include but also go beyond basic nutrients to encompass foods that aim at overall protection of health. The use of food-based dietary guidelines can improve policy coherence, by showing whether government recommendations for dietary intake based on expert opinion and in-country dialogue are affordable for consumers. In addition, our methods tap existing data and use simpler calculations, in contrast to the more stringent data requirements and linear programming method of the CoD approach. Countries may calculate CoRD and NPI from existing food price monitoring data, and track these easily with little added cost or expertise.

Few other studies have attempted to calculate the cost of dietary recommendations. One study that had calculated the cost of meeting dietary recommendations in the United States incorporated the cost of labor in food preparation, based on evidence that time constraints are an important factor in food choice (Mulik and Haynes-Maslow 2017). Accounting for the cost of labor in food preparation becomes important as the availability of fast foods and convenience foods, which tend

> 8Also, other work has found that across 15 countries in Asia and the Pacific, the price of food has increased faster than the overall CPI, and specifically the price of fruits and vegetables has increased faster than the rest of the overall food category (Dawe and Lee 2017).

> 9 It was initially designed to improve behavior change communication efforts around diet quality, and has since been used for advocacy around the need for improved affordability of nutritious diets, for example in Fill the Nutrient Gap (FNG) analyses done by the World Food Programme (WFP 2017).

> 10 In one district in Bangladesh, meeting nutrient needs was found to cost approximately $0.91; approximately 40–62 percent of households were found to be unable to afford a CoD-based diet, and the cost was higher in the lean season of the year (Chastre, Duffield, Kindness, LeJeune, and Taylor 2007). In Pakistan, 68 percent of households were unable to afford the minimum cost of a nutritious diet based on their current food expenditure, whereas only five percent of households were unable to afford the energyonly calorie poverty line diet. Non-affordability was highest in rural areas, while affordability was higher in Islamabad, despite the higher cost of food there (Pakistan, Ministry of Planning, Development & Reform, and WFP 2016). In Sri Lanka, the proportion of individuals who are unable to afford a nutritious diet is higher than those who are unable largely varies across provinces (WFP, MED and HARTI 2014). In Nepal, the cost of a CoD-based nutritious food basket also differs across agroecological zones (Biehl et al. 2016).

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