Calculating Mexico City’s Food Supply: Methodological Insights for Regionalizing Food Data at the Urban Scale

Abstract

Tackling the environmental impacts of food systems can play a crucial role in achieving urban sustainability. Robust accounts of urban food supply must inform policymaking. Current research on urban food supply often relies on extrapolating national data sets to the urban scale, obscuring the diversity of food consumption patterns across regions and across the urban–rural divide within countries. One illustration of this is the case of Mexico, where biocultural diversity has shaped diverse diets across the country. In this article, we present a method to estimate urban food supply in the data-scarce context of Mexico City. We combine national data on food supply with food consumption data from a spatially explicit food questionnaire to estimate urban food supply. We estimate the food supply for the Mexico City Metropolitan Area, breaking it down by food group, and present key differences with national-scale data. In particular, consumption of animal products (meat and milk) is higher than the national average, and corn consumption is lower. We conclude that it is crucial to produce precise accounts of urban diets to enable robust analyses of the environmental impacts of urban food supply, and reflect on the limitations and opportunities of our method.

Keywords:

• Diets
• food supply
• FAOSTAT
• food questionnaire
• food waste
• urban metabolism

Acknowledgements

The authors wish to thank María José Ibarrola Rivas for methodological insights that helped strengthen the elaboration of the method to estimate the MCMA’s food supply. The conclusion on the need to compare cities’ actual food metabolism with the needed food metabolism to achieve healthy diets for all urban dwellers was inspired by a talk given by Curtis Huffman in November 2020 at the Fourth International Student Colloquium on Population, Cities and the Environment at the Colegio de Mexico.

Notes

1 Food supply refers to the food available for human consumption (either through local production or importation) in a given territory. Food supply is either eaten or wasted; this explains why food supply numbers are necessarily higher than food consumption (the difference in both reflecting food waste). For the purposes of urban metabolism and sustainability research, food supply is the metric of most interest, given that it better reflects the overall amount of food that reaches the city (either through local production or through importation), whether it is consumed or not.

2 Quelites are seasonal edible green plants that play an essential role in the traditional rural Mexican diet and have recognized nutritional properties (Gomez-Chang et al. 2018).

3 The survey divides the country as North, Centre, South, and Mexico City Metropolitan Area.

4 Main Web sites used were www.kiwilimon.com, www.cocinafacil.com.mx, and www.mexicoenmicocina.com for home receipes, as well as super.walmart.com.mx, mx.openfoodfacts.org, and www.sams.com.mx for industrial foods.

5 To ensure the regional and national representativness of the survey, ENSANUT provides expansion factors, which are used to expand individual responses up to an estimate for the entire population. ENSANUT calculates the expansion factors as an inverse of the probability of selection, based on sociodemographic, geographic, and health characteristics of respondents.

6 Although maize can be consumed in many different ways, it is mostly consumed as tortillas (SAGARPA 2017). When comparing tortilla consumption to maize consumption, it is important to bear in mind that some water is added during the tortilla production process and therefore a tortilla’s weight is about 1.5 times higher than the weight of the maize required to produce it (Arnés and Astier 2019).

7 These studies diverge on the percentage of meat that is waste, ranging from 16 percent (Cuéllar and Webber 2010) to 47 percent (U.S. Department of Agriculture 2021).