About The Changing Global Diet
We built The Changing Global Diet website to tell the story of our investigations into changes in the diversity of crop plants that contribute to food supplies around the world, and to provide interactive visuals exploring these trends for all countries over the past 50 years.
About the data, analyses, and figures
We analyzed national per capita food supply data (picture this as the average food available to the average person in each country) for all available measurements [calories (kcal/capita/day), protein (g/capita/day), fat (g/capita/day), and food weight (g/capita/day)] reported by the United Nations Food and Agriculture Organization Statistics Office (FAOSTAT). National food supply data for plants is calculated by measuring national production of these crops, plus any imports, plus or minus any national food reserve changes during that year; minus any exports, any quantities used for seed, animal feed, or in the manufacture of non-food products, and minus any losses that could be measured during storage and transport of the food. Food supply data offers an approximation for diet, which is very difficult to measure in standardized ways around the world, e.g., because it is challenging to account for how much of this food is wasted or otherwise not eaten by people within their households, versus how much is actually consumed.
We analyzed all the crop commodities and countries reported in the FAO database, standardized across all years (1961 to 2009). Plant commodities clearly comprised of the same crop species were aggregated into single commodities representing the crop species, for example, olive oil and olives were combined. After aggregation, a total 53 crop commodities remained. Animal foods were included within the analysis as a single aggregated commodity where needed to place the findings in the context of the total food supply.
In order to align all time periods and include as much of the world’s population as possible, the current nations formerly comprising the USSR, Yugoslav SFR, Ethiopia PDR, and Czechoslovakia were aggregated into their former states, with national data merged by weighted average based upon population of the respective states at the respective reporting year. Belgium and Luxembourg were reported together from 1961 to 1999, and, therefore, recent years listing the countries separately were merged as above. The resulting 152 comparable countries comprised 98% of the world’s population across the study period (1961 to 2009).
We examined the total amounts of food contributing to national food supplies, both by food group and by each specific crop, in each country in each year. We also counted the total number of crops contributing to food supplies. We used Pielou’s evenness index to measure how equally crops contributed to each country’s food supplies in each year. We also analyzed changes in dominance, defined as the change in the contribution of the most abundant crop commodity in each country in each year. We quantified the similarity of countries’ food supplies by calculating the Bray-Curtis distance (dissimilarity) from each country to the global centroid (comparable to the global mean commodity composition, which is inclusive both of the number of crops and also of the relative abundance/evenness of crops) in each year, with similarity derived by subtracting dissimilarity from 1. We further interpreted similarity using a non-metric multidimensional scaling analysis (NMDS) analyzed in three dimensions for convergence and visualized in two, with Bray-Curtis dissimilarities used to compare changes across decades (data points for each country were averaged across 1961 to 1969, 1970 to 1979, 1980 to 1989, 1990 to 1999, and 2000 to 2009). To provide further estimates of the diversity of each country’s current food supply (annual national per capita data averaged across 2009 to 2011), in addition to the total number of crops reported, we calculated two diversity metrics (Shannon’s and Simpson’s) that account not only for the total number of crops, but also the relative abundance/evenness of each crop. Analyses were performed in R packages “vegan” and “lme4”. Interactive figures were built in Tableau.
This poster displays some of the major changes in the diversity of countries’ food supplies worldwide over the past 50 years (online version | printable version).
The graph repository below contains an assortment of downloadable figures on changes in food supplies and production systems in various countries, and as a global average.
The Changing Global Diet was built by Sara Kammlade, Colin K. Khoury, Steven Sotelo, Harold Achicanoy, Anne Bjorkman, and Carlos Navarro-Racines, at the International Center for Tropical Agriculture (CIAT). This is Version 1.0 (April 2017). This work is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0).
The data and analyses shown here are associated with the publication:
Khoury CK, Bjorkman AD, Dempewolf H, Ramírez-Villegas J, Guarino L, Jarvis A, Rieseberg LH and Struik PC (2014). Increasing homogeneity in global food supplies and the implications for food security. PNAS 111(11): 4001-4006. doi: 10.1073/pnas.1313490111.
For an assortment of examples of media coverage of the published research, see these articles in National Geographic
| Guardian | BBC | Time Magazine | NBC | NPR | LA Times | Reuters | Scientific American | Scientific American graphic | Voice of America | Slate | Eat This Podcast | The Scientist.
We’d love to hear from you about the changes in food supplies that you find interesting. Build and share your own infographics, and tell the story with the hashtag #changingglobaldiet.