William A. Masters

1. Access to nutritious diets as a policy indicator for agricultural transformation and healthy food systems William A. Masters Friedman School of Nutrition and Dept of Economics, Tufts University http://sites.tufts.edu/willmasters ICABR session on Food Systems, 6 June 2019

2. Access to nutritious diets as a policy indicator motivation | methods & data | results Why measure the cost of nutritious diets? • Rural and urban food markets are changing rapidly • from own-production to use of markets • from generic commodities to branded, packaged foods • lower cost of starchy staples relative to milk, eggs, meat, fruit & veg • higher earnings, allowing more choice among affordable foods • To monitor change, we need new kinds of price indexes • existing indexes focus on trade, producer prices, or the cost of living • we add nutritional data, to measure the cost of a healthy diet • comparison to earnings reveals affordability at each time and place • Measuring access to nutritious diets can guide intervention • where do diet costs exceed earnings, so transfers are needed? • which foods & nutrients drive costs up, so access can be improved? • are some foods already accessible at low cost, but under-consumed? Photo by Anna Herforth at Nsawam market, Ghana

3. Access to nutritious diets as a policy indicator motivation| methods & data | results We construct food price indexes representing least-cost diets for nutrient adequacy and daily subsistence at each place and time • All essential nutrients required for long-term health Cost of nutrients = min. { C = Σipi × qi } least-cost combination of foods With:Σiaie× qi  = Edaily energy balance Σiaij × qi ≥ EARjestimated average requirements Updated to address dietary transition: Σiaij × qi ≤ ULjupper limits for toxicity Σiaij × qi ≤ AMDRj,u×E/ej Σiaij × qi ≥ AMDRj,l ×E/ej • Parameter values are Dietary Reference Intake (DRI) requirements for the US and Canada, last revised by the Institute of Medicine in 2011 • Use a total of 20 nutrients and 35 constraints, omitting DRIs for Vitamin D & cholesterol due to synthesis in the body, and iodine & molybdenum due to lack of nutrient composition data • Baseline is woman 19-30, can adjust for age, sex, pregnancy & lactation • Baseline is ~2000 kcal/day, can adjust for physical activity level Comparison is just subsistence energy from starchy staples • within acceptable macronutrient distribution ranges

4. Access to nutritious diets as a policy indicator motivation| methods & data | results Nutrient needs vary over the life course and across people We use average requirements, to meet needs of a median healthy person -- We also compare to recommended daily allowances (RDAs), to meet needs of almost all people (97.5%) Our base case is an adult woman -- We also compare across individuals, to meet needs of whole households Source: Calculated from Institute of Medicine (2011), Dietary Reference Intakes. https://www.ncbi.nlm.nih.gov/books/NBK56068.

5. Access to nutritious diets as a policy indicator motivation| methods & data | results Nutrient needs call for a diverse, well-balanced diet Dietary reference intake levels of essential nutrients for healthy adult (median woman aged 19-30, not pregnant or lactating) Chronic disease risk Potential toxicity Source: Calculated from Institute of Medicine (2011), Dietary Reference Intakes. https://www.ncbi.nlm.nih.gov/books/NBK56068.

6. Access to nutritious diets as a policy indicator motivation| methods & data | results Matching prices of locally-available foods with their nutrient content reveals which foods can meet nutrient needs at lowest total cost Number of foods available and included in least-cost diets for nutrient adequacy A typical least-cost diet uses only 6-8 foods to meet all nutrient constraints, but composition varies Note: Items shown are all foods and non-alcoholic beverages with prices in ICP 2011, matched to nutrient content in USDA Standard Reference food composition database. Source: Alemu et al. (2019), calculated from World Bank International Comparison Project (ICP) data.

7. Access to nutritious diets as a policy indicator motivation| methods & data | results Least-cost diets identify the diverse foods needed in each country Number of foods included in least-cost diets, by COICOP category Least-cost diets have more diversity across food groups than many actual diets Most least-cost diets include only one food from each category, except starchy staples, vegetables & legumes Note: Foods are shown here using the UN system’s Classification of Individual Consumption by Purpose (COICOP) categories, for consistency with ICP data. Source: Alemu et al. (2019), calculated from World Bank International Comparison Project (ICP) data.

8. Access to nutritious diets as a policy indicator motivation| methods & data | results Least-cost diets identify which nutrient constraints are binding Frequency with which each nutritional requirement is a binding constraint Minimum requirements for calcium, vitamins C, A, E, B12 and other micronutrients often drive diet costs Macronutrient balance is also often binding Upper limits of toxicity are rarely a concern Source: Alemu et al. (2019), calculated from World Bank International Comparison Project (ICP) data.

9. Access to nutritious diets as a policy indicator motivation| methods & data | results Least-cost diets measure the cost of nutrients and calories relative to a country’s overall price level Nutrient adequacy costs over cost over half of the $1.90 poverty line and is twice as expensive as daily energy US$/day at 2011 PPP food prices Darker: Cost of nutrient adequacy Lighter: Cost of caloric adequacy $1.90/day 50% ($0.85/day) Source: Alemu et al. (2019), calculated from World Bank ICP data. Results shown are daily cost of adequate nutrients (in black) and subsistence calories from starchy staples (in gray), using locally-available foods at retail prices reported to the ICP, converted from local currency units at each country’s average price level for all food. Nutritional adequacy is computed based on U.S. and Canada Dietary Reference Intake (DRI) estimated average requirements for calories and 17 essential nutrients to sustain a healthy adult woman, as well as upper limits for toxicity and acceptable macronutrient distribution ranges.

10. Access to nutritious diets as a policy indicator motivation| methods & data | results Least-cost diets identify hotspots, with high cost of nutrients relative to the cost of daily calories from starchy staples Nutrient adequacy costs over 3x the cost of subsistence in many low-income countries (and in many high-income countries too) Cost of nutrients/ cost of calories Source: Alemu et al. (2019), calculated from World Bank ICP data on food prices and DRI data on nutrient requirements.

11. Access to nutritious diets as a policy indicator motivation| methods & data | results In poorer countries all food prices are relatively high, compared to earnings and non-food prices Price levels relative to all household expenditure Source: Alemu et al. (2019), calculated from World Bank International Comparison Project (ICP) data.

12. Access to nutritious diets as a policy indicator motivation| methods & data | results In the poorest countries, nutritious diets would cost a large fraction of all household expenditure Cost of nutrient adequacy relative to all household expenditure Cost of nutrients/ all expenditure Source: Alemu et al. (2019), calculated from World Bank International Comparison Project (ICP) data.

13. Access to nutritious diets as a policy indicator motivation| methods & data | results The only significant correlates of relative nutrient costs we find, after controlling for income and region, are rural proximity to towns & rural electrification Note: Standard errors in parentheses, with significance levels denoted *** p<0.01, ** p<0.05, * p<0.1, from robust regressions (rreg). All specifications include indicator variables for ICP regions (not shown).

14. Access to nutritious diets as a policy indicator motivation| methods & data | results Applications within countries reveals spatial and temporal patterns In Tanzania, we have prices for 64 items from 21 regions, 2011-15 Seasonality in diet costs varies among foods in the timing, duration and magnitude of seasonal peaks Starchy staples Width shows estimated period of higher prices Dark dots show statistically significant peaks Colors show magnitude of seasonal rise Seasonal rises in the cost of nutrients are greatest in southern regions Pulses Animal foods (and processed foods) have the least seasonality Animal foods Fruits and Vegetables Fruits and vegetables have the most seasonality, and also variation in peak timing Oils, fats & other foods Source: Bai et al. (2019)

15. Access to nutritious diets as a policy indicator motivation| methods & data | results Applications within countries reveals long-term trends & fluctuations Trends in the costs of nutrient adequacy, caloric adequacy and real wages in Ethiopia, 2001-2017 (2011 PPP $/day) In Ethiopia, we have prices for 92 items at 120 markets, 2001-17 with monthly wages at each location Daily wages ($/day) • Since 2008, • Wages for unskilled manual workers (e.g. construction) have doubled, from ~$4 to $8/day in PPP terms • Cost of nutrient adequacy has risen by about 25%, while the cost of daily calories has fallen by about 20% • Trends reflect policy orientation toward jobs growth and green revolution cereal crop production • To address malnutrition, policy will need to target nutrient-dense foods Real wages for unskilled workers (right scale) Diet costs ($/day) Cost of nutrient adequacy Cost of caloric adequacy Source: CANDASA results, from Bachewe et al. (2019)

16. Access to nutritious diets as a policy indicator motivation| methods & data | results Price trends reveal new challenges, beyond green revolution success Price trends by food group in Ethiopia, 2001-2017 (2011 PPP $/day) Since 2008, green revolution success Source: CANDASA results, from Bachewe et al. (2019)

17. Access to nutritious diets as a policy indicator motivation| methods & data | results Implications for policy analysis and intervention • From global analysis, high cost of nutritious foods reveals role of: • safety-net transfers to raise affordability, in addition to • food system changes to improve relative costs, and • behavioral interventions to influence food choice • From analysis within Tanzania and Ethiopia, market-level data reveal: • Greater seasonality and spatial variation for nutritious foods than starchy staples • After wage growth and cereal productivity gains, need to focus on other food groups • Other work including data from Malawi, Ghana and India addresses: • Heterogeneity in nutrient requirements and diet costs • Aggregation from individual diets to household consumption • Improvements in local food composition data • Price indexes based on food-group recommendations • Using diet costs to measure food system change is very promising

18. Thank you! Details here: https://sites.tufts.edu/willmasters Co-authors: Robel Alemu, Yan Bai & Kate Schneider, PhD students, and Steven Block (Tufts University); Anna Herforth (Consultant); Daniel Sarpong (University of Ghana); Fulgence Mishili (Sokoine University, Tanzania); Stevier Kaiyatsa (Government of Malawi); Derek Headey, Fantu Bachewe & Kalyani Raguthanan (IFPRI) This research is supported by USAID through the Rutgers University Feed the Future Policy Consortium (USDA award # TA-CA_15_008), and by UKAid with the Bill & Melinda Gates Foundation through the CANDASA project (OPP1182628) Food price measurement is not easy Photo: Anna Herforth, 2017