We provide methods and data for tracking lowest-cost items by food group, used by FAO and the World Bank for joint monitoring of global food environments, and by national governments for monitoring within countries. This approach to measuring food access helps decision makers distinguish among causes of poor diet quality, allowing policy analysts to guide interventions aimed at universal access to healthy diets. You can scroll down this page for our results and citations to how this project relates to previous and related work.
Data visualization and download options for global analysis of
diet cost and affordability:
RESEARCH & PUBLICATIONS
Recommended citations and reference materials
- Recommended citations to latest global data, published jointly by FAO and the World Bank
- FAO (2024), Cost and Affordability of a Healthy Diet database, updated 24 July 2024. Rome, FAO. https://www.fao.org/faostat
- World Bank (2024), Food Prices for Nutrition database, version 3.0, updated 24 July 2024. Washington, DC: The World Bank. https://doi.org/10.57966/41AN-KY81
- Prepared tables to download the most important cost and affordability variables, which can readily be matched with other variables such as national income and food insecurity.
- Other data visualization and discussion is in a joint FAO-Tufts-World Bank blog post, or independent analysis at Our World in Data and the Food System Dashboard
- Summaries of methods and data sources
- Wallingford, J., S. de Pee, A.W. Herforth, S. Kuri, Y. Bai and W.A. Masters (2024). Measuring food access using least-cost diets: Results for global monitoring and targeting of interventions to improve food security, nutrition and health. Global Food Security, 41: 100771.
- Herforth, A., A. Venkat, Y. Bai, L. Costlow, C. Holleman, & W.A. Masters (2022). Methods and options to monitor the cost and affordability of a healthy diet globally. Background paper for the State of Food Security and Nutrition in the World 2022. FAO Agricultural Development Economics Working Paper 22-03. Rome, FAO. (Used for special section of SOFI reports: SOFI 2022, SOFI 2023).
- First use as official statistics by a country government
- National Bureau of Statistics, Nigeria (2024). Cost of a Healthy Diet Monthly Bulletin. Abuja: NBS. (FAQs, press briefing, news coverage, independent local analysis).
- First study using lowest-priced items by food group as a metric of access to a global dietary standard
- Masters, W.A., Y. Bai, A. Herforth, D. Sarpong, F. Mishili, J. Kinabo, and J.C. Coates (2018). Measuring the affordability of nutritious diets in Africa: price indexes for diet diversity and the cost of nutrient adequacy. American Journal of Agricultural Economics 100(5): 1285-1301. [replication file]
- First global analysis of diet cost per day as a metric of affordability
- Herforth, A., Y. Bai, A. Venkat, K. Mahrt, A. Ebel & W.A. Masters (2020). Cost and affordability of healthy diets across and within countries. Background paper for FAO, IFAD, UNICEF, WFP and WHO, The State of Food Security and Nutrition in the World 2020. FAO Agricultural Development Economics Technical Study No. 9. Rome: FAO. (Link to special section of SOFI 2020).
- Instructional materials from the project
- World Bank Open Learning Campus (2023). Food Prices for Nutrition: Cost and Affordability of a Healthy Diet and other Indicators. Self-paced eLearning course (approx. 6 hours). Washington, DC: The World Bank.
- Food Prices for Nutrition (2024). Software tools for calculating the Cost of a Healthy Diet, Version 6.0. (+tutorial video) Boston: Tufts University.
- Instructional materials for context and background
- Masters, W.A., A.B. Finaret and S.A. Block (2022). The economics of malnutrition: Dietary transition and food system transformation. Handbook of Agricultural Economics, vol. 6: 4997-5083. Amsterdam: Elsevier. (preprint)
- Masters, W.A. and A.B. Finaret (2024). Food Economics: Agriculture, nutrition and health. New York: Palgrave MacMillan. (+instructor support site)
- Wallingford, J.K. and W.A. Masters (2024). Least-cost diets to teach optimization and consumer behavior, with applications to health equity, poverty measurement and international development. Journal of Economic Education, forthcoming.
Peer-reviewed journal articles from the project (most recent first)
- Herforth, A.W., R. Gilbert, K. Sokourenko, T. Fatima, O. Adeyemi, D. Alemayehu, E. Arhin, F. Bachewe, Y. Bai, I. Chiosa, T. Genye, H. Haile, R. Jahangeer, J. Kinabo, F. Mishili, C.D. Nnabugwu, J. Nortey, B. Ofosu-Baadu, A. Onabolu, D. Sarpong, M. Tessema, D. TT. Van, A. Venkat and W.A. Masters (2024). Monitoring the Cost and Affordability of a Healthy Diet within countries: Building systems in Ethiopia, Ghana, Malawi, Nigeria, Pakistan, Tanzania, and Viet Nam. Current Developments in Nutrition, vol. 8: e104441.
- Narayanan, S., K. Raghunathan and A. Christopher (2024), Beyond the Consumer Price Index: Measuring the Cost of a Healthy Diet in India. Economic and Political Weekly, 59(10): 48-56. (preprint)
- Headey, D.D., K. Hirvonen and H. Alderman (2024). Estimating the cost and affordability of healthy diets: How much do methods matter? Food Policy, 126: 102654
- Wallingford, J., S. de Pee, A.W. Herforth, S. Kuri, Y. Bai and W.A. Masters (2024). Measuring food access using least-cost diets: Results for global monitoring and targeting of interventions to improve food security, nutrition and health. Global Food Security, 41: 100771.
- Gilbert, R., L. Costlow, J. Matteson, J. Rauschendorfer, E. Krivonos, S.A. Block and W.A. Masters (2024). Trade policy reform, retail food prices and access to healthy diets worldwide. World Development, 177: 106535.
- Headey, D.D., F. Bachewe, Q. Marshall, K. Raghunathan and K. Mahrt (2024). Food prices and the wages of the poor: A cost-effective addition to high-frequency food security monitoring. Food Policy 125: 102630.
- Wallingford, J., E.M.Martinez and W.A. Masters (2023), COVID-19 mobility restrictions and stay-at-home behaviour in 2020 were associated with higher retail food prices worldwide. Global Food Security e100702. [replication file]
- Headey, D.D. and M. Ruel (2023), Food inflation and child undernutrition in low and middle income countries. Nature Communications 14: 5761. [replication file]
- Headey, D.D. and K Hirvonen (2023), Higher food prices can reduce poverty and stimulate growth in food production. Nature Food 4: 699-706. [replication file]
- Headey, D.D., O. Ecker, A.R. Comstock and M.T. Ruel (2023). Poverty, price and preference barriers to improving diets in sub-Saharan Africa. Global Food Security 36: 100664.
- Bai, Y., L. Costlow, A. Ebel, S. Laves, Y. Ueda, N. Volin, M. Zamek and W.A. Masters (2022). Retail prices of nutritious food rose more in countries with higher COVID-19 case counts. Nature Food 3: 325–330.
- Bai, Y., A. Herforth and W.A. Masters (2022). Global variation in the cost of a nutrient-adequate diet by population group. Lancet Planetary Health, 6(1): e19-e28.
- Schneider, K.R., L. Christiaensen, P.J. Webb & W.A. Masters (2022), Assessing the affordability of nutrient-adequate diets, American Journal of Agricultural Economics, e12334. [preprint]
- Schneider, K.R. (2022). Nationally representative estimates of the cost of adequate diets, nutrient level drivers, and policy options for households in rural Malawi. Food Policy, p.102275.
- Bai, Y., L. Costlow, A. Ebel, S. Laves, Y. Ueda, N. Volin, M. Zamek, A. Herforth, and W.A. Masters (2021). Retail consumer price data reveal gaps and opportunities to monitor food systems for nutrition. Food Policy 104: e102148.
- Laborde, D., A. Herforth, D. Headey, and S. de Pee (2021). COVID-19 pandemic leads to greater depth of unaffordability of healthy and nutrient-adequate diets in low- and middle-income countries. Nature Food 2(7): 473–75.
- Raghunathan, K., D. Headey and A. Herforth (2020), Affordability of nutritious diets in rural India. Food Policy, 99: e101982. [media: Hindustan Times, The Hindu]
- Hirvonen, K., Y. Bai, D. Headey and W.A. Masters (2020), Affordability of the EAT–Lancet reference diet: a global analysis. Lancet Global Health, 8(1): e59-e66. [media, tv, webinar, journal cover, summary]
- Bai, Y., R. Alemu, S.A. Block, D. Headey and W.A. Masters (2020). Cost and affordability of nutritious diets at retail prices: evidence from 177 countries. Food Policy, e101983.
- Bai, Y., E. Naumova and W.A. Masters (2020). Seasonality in diet costs reveals food system performance in East Africa. Science Advances, eabc2162.
- Schneider, K.R. & A. Herforth (2020). Software tools for practical application of human nutrient requirements in food-based social science research. Gates Open Research 4:179.
- Dizon, F., A. Herforth and Z. Wang (2019), The cost of a nutritious diet in Afghanistan, Pakistan and Sri Lanka. Global Food Security 21(June): 38-51.
- Masters, W.A., Y. Bai, A. Herforth, D. Sarpong, F. Mishili, J. Kinabo, and J.C. Coates (2018). Measuring the affordability of nutritious diets in Africa: price indexes for diet diversity and the cost of nutrient adequacy. American Journal of Agricultural Economics 100(5): 1285-1301. [replication file]
Preprints under review at peer-review journals (most recent first)
- Masters, W.A., J.K. Wallingford, A.W. Herforth and Y. Bai (2024), Measuring food access using the Cost of a Healthy Diet (CoHD): Insights from retail prices worldwide. Food Prices for Nutrition project working paper. Boston: Tufts University.
- Herforth, A., Y. Bai, A. Venkat, and W.A. Masters (2024). The Healthy Diet Basket: A global standard for comparing the cost of healthy and sustainable diets. Food Prices for Nutrition project working paper. Boston: Tufts University. (Also available as an infographic poster.)
- Martinez, E.M., N.T. Blackstone, P. Wilde, A.W. Herforth and W.A. Masters (2024), Environmental impacts, nutritional profiles, and retail prices of commonly sold retail food items in 181 countries. Food Prices for Nutrition project working paper. Boston: Tufts University.
- Costlow, L., A. Herforth, T.B. Sulser, N. Cenacchi and W.A. Masters (2024), How and where global food supplies fall short of healthy diets: Past trends and future projections, 1961-2020 and 2010-2050. Food Prices for Nutrition project working paper. Boston: Tufts University.
Book chapters and commentary articles in scholarly journals (most recent first)
- Bai, Y. and W.A. Masters (2024). Complex dynamics between food prices, income and dietary quality in sub-Saharan Africa. Nature Food 5(3): 196-197.
- Masters, W.A., E.M. Martinez, F. Greb, A. Herforth and S.L. Hendriks (2023), Cost and affordability of preparing a basic meal around the world, in J. von Braun et al., eds, Science and Innovations for Food Systems Transformation, pages 603-623.
- Kennedy, E.T., M.A. Torero, D. Mozaffarian, W.A. Masters, R.A. Steiner, S.L. Hendricks, J.A. Morrison, K.K. Merrigan, S.A. Ghosh and D.E. Mason-d’Croz (2023), Beyond the Food Systems Summit: Linking Recommendations to Action – The True Cost of Food. Current Developments in Nutrition, e100028.
- Headey, D.D. and K. Hirvonen (2022), Food inflation and global poverty. Royal Economic Society Newsletter 199 (October): 14-17.
Official policy reports and institutional publications (most recent first)
- Wallingford, J.K., S. de Pee, A.W. Herforth, S. Kuri, Y. Bai, R.D. Gilbert and W.A. Masters (2024), Using food prices to calculate least-cost healthy and nutrient adequate diets helps inform social protection efforts worldwide, Policy in Focus, Vol. 1, No. 1: 52-55. Brasília: World Food Programme (WFP) and the Institute for Applied Economic Research, Government of Brazil.
- Fatima, T., R.D. Gilbert, A.W. Herforth and R.A. Jahangeer (2024), Measuring the Cost and Affordability of a Healthy Diet in Pakistan. Islamabad: FAO.
- Bai, Y., J. Bouscarat, K. Sokourenko, P. Heinrigs and K. Zougbédé (2023), Healthy diets, costs and food policies in the Sahel and West Africa. West Africa Papers No. 39, Paris: OECD.
- Alemayehu, D., F.N. Bachewe, T. Genye, R. Gilbert, H. Haile, D. Headey, W.A. Masters, A. Herforth and M. Tessema (2023), Implementation of the Ethiopian Food-Based Dietary Guidelines: Analysis of cost and affordability of healthy diets, January 2020 – December 2022. Food Science and Nutrition Research Directorate Scientific Newsletter. Addis Ababa: Ethiopian Public Health Institute (EPHI).
- Mahrt, K., A. Herforth, S. Robinson, C. Arndt and D.D. Headey (2022), Nutrition as a basic need: a new method for utility-consistent and nutritionally adequate food poverty lines. Discussion Paper 2120. Washington, DC: IFPRI. [video]
- Kaiyatsa, S., K. Schneider and W.A. Masters (2021), How sensitive are cost of living metrics to missing food price data? Evidence from a novel market survey and consumer price data in rural Malawi. Food Prices for Nutrition project background paper. Boston: Tufts University.
- Mahrt, K., D.L. Mather, A. Herforth, and D. Headey (2019), Household dietary patterns and the cost of a nutritious diet in Myanmar. Discussion Paper 1854. Washington, DC: IFPRI.
- Dizon. F. and A. Herforth (2018), The cost of nutritious food in South Asia. Policy Research Working Paper Series. Washington, D.C.: The World Bank Group.
- Masters, W.A., Y. Bai, A. Herforth, D. Sarpong, F. Mishili, J. Kinabo, and J.C. Coates (2017). Measuring the cost of dietary diversity: Novel price indexes to monitor access to nutritious diets. Trade Policy Technical Note No. 20 (November). Rome: FAO.
LINKS TO PREVIOUS AND RELATED WORK
The diet cost and affordability metrics developed by the Food Prices for Nutrition project build on a long tradition of other work on food prices and nutrition, applied to global monitoring of food environments as called for by Herforth (2015) and Herforth and Ahmed (2015) among others. We use nutritional requirements for a healthy diet to construct new kinds of food price indexes to monitor change and differences across and within countries. Our central innovation is to measure food access using the least expensive locally available items that would meet dietary requirements for essential nutrients and food groups, first for Ghana and Tanzania in Masters et al. (2018) and globally by Herforth et al. (2020). The Food Prices for Nutrition project developed new ways to use data collected for other purposes, using generic software to convert price observations into diet costs as a new kind of price index for monitoring access to healthy diets.
Using least-cost diets to measure food access is a vibrant and growing area of research and practice, and we look forward to sharing ideas and learning from diverse investigators and practitioners working in this domain around the world. This builds on and facilitates a wide range of other work, including the important precursors and ongoing complements to our project listed below.
Previous and related work using the cost of nutrient adequacy to measure food environments
- Since the initial formulation of least-cost diets for nutrient adequacy of Stigler (1945), many applications have used mathematical programming and modeled diets to address a variety of research and policy questions.
- In nutrition, recent work on the cost per day of foods needed for nutrient adequacy was pioneered by Darmon et al. (2002) for adults in France, with applications to nutrition assistance ranging from the U.S. Thrifty Food Plan analyzed by Wilde and Llobrera (2009) to the Optifood approach to infant feeding in low-income settings led by Ferguson et al. (2008), and the related ‘Cost of the Diet‘ for households from Chastre et al. (2007) and Deptford et al. (2017) most recently applied in Malawi by Rana (2022, 2023, 2024). Similar models are applied in high-income countries such as Conforti and D’Amicis (2020) for households in Italy and Stern et al. (2023) for school meals in the US. Large-scale global use of these techniques has been driven by de Pee et al. (2017) [link], in the World Food Program’s work to Fill the Nutrient Gap. Calculation of least-cost nutrient adequate diets and meals can be done through a web browser with prepared data and software as done by the St. John’s Research Institute in India.
- In economics, the first modern use of least-cost nutrient adequate diets to track change in food systems over time was O’Brien-Place and Tomek (1983) for the United States, and the pioneering modern application to poverty measurement and social protection across countries globally is Allen (2017). At the same time, Omiat and Shively (2017) demonstrated the potential of least-cost nutrient adequate diets to track temporal and spatial variation using locally-available price data in Uganda, and Moatsos (2021) used similar methods to track long term historical trends in access to sufficient foods for nutrient adequacy in the world as a whole. The use of least-cost diets in poverty measurement is described by Stehl, Depenbusch and Vollmer (2023) and Moatsos (2024).
Adoption of Food Prices for Nutrition methods using the cost of a healthy (recommended) diet for food policy analysis
- The formulation of food-based dietary guidelines allows use of least-cost items in each food group to track access to a healthy diet. Beyond our own project’s studies, Mekonnen et al. (2021) and Mekonnen et al. (2023) estimated the affordability of healthy diets in Nigeria, while Gupta et al. (2021) explore the cost of the EAT-Lancet diet in rural India, and Mwambi et al. (2023) measure the cost of meeting local FBDGs in Thailand and the Philippines. Parallel work at the World Bank was led by Dizon et al. (2019) for Bangladesh, Sri Lanka, Pakistan, and Afghanistan, and then Dizon et al. (2021) for Bangladesh, Bhutan, India and Nepal, as well as Dizon and Wang (2021) with additional detail for India. The same methods are increasingly used by IFPRI country offices for policy analysis as in Papua New Guinea by Schmidt, Fang, and Mahrt (2022), in Rwanda by Warner and Manners (2024), and by the Myanmar Agriculture Policy Support Activity (2024). Research on food access using the cost of healthy diets may be based on new price data collection such as Islam et al. (2023) in Bangladesh, or provide further analysis of the global cross-country comparisons as published by the Food Prices for Nutrition project such as Ambikathi et al. (2022).
- The studies above focus costs per day, using quantities needed for health. An earlier approach focuses on relative prices per serving or unit of dietary energy, as done for the U.S. and Europe by Drewnowski and Darmon (2005) as well as Carlson and Frazão (2012) for the US, and Wiggins et al. (2015) for Brazil, China, Korea, Mexico and the UK, adding to early literature reviewed by Rao et al. (2013), expanded to all countries of the world for food groups by Headey and Alderman (2019) and for a single ‘basic plate’ of standard foods by WFP (2020) , with continued work on price changes by food group such Batis et al. (2022) in Mexico or de Mello et al. (2022) in Brazil.
- To measure food environments more broadly, a closely related line of work aims to measure how retail prices among other factors affect obesity and other diseases, as pioneered by the INFORMAS network of Swinburn et al. (2013), including work on the price and affordability of healthy vs. unhealthy foods described by Lee et al. (2013) with ongoing applications in Africa led by Laar et al. (2022). Much of this research focuses on adherence to normative dietary guidelines and the cost of predefined food groups as in Gama et al. (2015) for children in Brazil, but some uses the cost of dietary patterns observed in healthier or less healthy people as in the work of Clark and Mendoza-Gutierrez et al. (2021) in Mexico.
How innovations brought by the Food Prices for Nutrition project complement and amplify other work
Methods for monitoring and analysis of diet costs developed by the Food Prices for Nutrition project complement and amplifies previous work in several ways:
- First, we focus on methods for transformation of previously collected data. Our aim is to help national statistical organizations and international agencies use their existing price data collection and analysis systems to monitor food access for healthy diets on a routine basis, by combining data on:
- availability and price of retail foods at local marketplaces, leveraging data collected by national statistical organizations to monitor inflation or by international agencies for early warning systems to guide intervention;
- nutritional composition of each item from global and regional food composition tables, allowing analysts to transform prices for hundreds of differentiated items into cost per unit of each food group, accounting for edible fraction and water weight, as well as cost per unit of each nutrient;
- dietary requirements for an active and healthy life, using national food-based dietary guidelines as well as upper and lower bounds for essential nutrients, and then automating the selecting of least-cost items needed for a healthy diet in each setting;
- available income of households in each population, taking account of other basic needs and adjusting for the purchasing power of local currencies, generating a variety of affordability metrics for a variety of policy or program purposes.
- Second, we aim for worldwide use, with both default standards and also customized solutions to address specific needs in particular settings, helping institutions develop monitoring systems adapted to their circumstances. This work is conducted in partnership with the World Bank and IFPRI and includes:
- the global Healthy Diet Basket approach based on national dietary guidelines from all regions of the world, created in partnership with FAO and other UN agencies for monitoring food security and nutrition worldwide;
- country studies using local dietary guidelines, created in partnership national statistical organizations and public health institutions, especially in our nine priority countries (Bangladesh, India, Pakistan, Burkina Faso, Ethiopia, Ghana, Malawi, Nigeria, and Tanzania);
- developing new and improved approaches advancing the frontier of research, with students and collaborators around the world.
- Finally, we support the improvements in food price data collection and reporting needed to monitor nutritional needs. This includes use of locally appropriate information on food composition and nutritional requirements, but in some cases also expansion of primary data collection to ensure coverage of:
- item prices and availability in all food groups needed for a healthy diet — this is most important when using prices collected in market information and early warning systems that focus on farm commodities, whose food lists can be expanded to cover diverse vegetables, fruits, fish and other foods also available in local markets as demonstrated in early work with the WFP on the value of an expanded food list in Ghana;
- prices and availability of low-cost items in popular markets used by people at risk of malnutrition — this is most important when using prices collected to monitor inflation, so their focus is national average spending which is dominated by higher-price items purchased by high-income people in urban markets, requiring expansion of data collection to marketplaces where lower-income people acquire their food, often in more remote locations as discussed in price differences by location in Malawi.
- Visitors interested in seeing how various countries currently monitor and report food price inflation can see Malawi’s National Statistical Office (NSO) reports here. For Ghana, visitors can track retail prices of individual foods from the Ministry of Food and Agriculture (MoFA) here, and see the Ghana Statistical Service (GSS) inflation monitoring here. The worldwide posting of food prices is the subject of our recent paper on gaps and opportunities to monitor food systems for nutrition in Food Policy (2021). The first country to use the project’s approach to monitoring food access in official national statistics is Nigeria, with the first monthly bulletin released in January 2024, as explained by the National Bureau of Statistics’ FAQs and press briefing. This builds on related work in Ethiopia, focused on access to their new national dietary guidelines.
Monitoring food access for healthy diets is a rapidly expanding field of work, involving close collaboration between a wide range of stakeholders. We look forward to hearing from you about opportunities to advance this urgent agenda for research and practice to meet global development goals.
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