Capacity of the US food system to accommodate improved diet quality: A biophysical model projecting to 2030

Authors: Conrad, Zachary; JOHNSON, LUANN - University Of North Dakota; PETERS, CHRISTIAN - Tufts University; Jahns, Lisa

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2018
Publication Date: 4/1/2018
Publication URL: http://handle.nal.usda.gov/10113/6250413
Citation: Conrad, Z.S., Johnson, L., Peters, C.J., Jahns, L.A. 2018. Capacity of the US food system to accommodate improved diet quality: A biophysical model projecting to 2030. Current Developments in Nutrition. 2(4). https://doi.org/10.1093/cdn/nzy007.
DOI: https://doi.org/10.1093/cdn/nzy007

Interpretive Summary: Americans’ diet quality has been low for decades, but there have recently been some improvements. Little is known about whether the US agricultural system can produce enough food to support a shift toward healthier eating. We used a computer model to estimate how many Americans could be fed higher quality diets if we produced all of our food in the United States, and whether there would be changes in the amount of cropland needed. We acquired data on food consumption from a national survey, national-level crop yield data, and population size, and entered these data into the computer model. The US agricultural system can produce enough food to feed nearly 1.5 times its population, and a greater number of people can be fed a high quality diet than a low quality diet. Yet substantial shifts in cropland acreage would be needed if Americans improved their diet quality, which is dependent on farmers’ ability to shift production to other crops and the ability of the food supply chain to adapt to changing consumer demand.

Technical Abstract: Background: Increasing Americans’ diet quality will require changes to the food supply. Due to the complex nature of the food system, this is not as straightforward as simply increasing the production of healthy foods and decreasing the production of unhealthy foods. Little is known about whether the US food system can produce enough food, given finite agricultural resources, to support shifts toward healthier eating patterns. Objective: To model the capacity of the US food system to accommodate a shift toward a healthier diet by 2030. Methods: A biophysical simulation model estimated the proportion of the US population that could be fed a given diet based food system constraints, currently and projected to 2030. The model accepted data inputs on food intake, crop yields, and population size. Linear and non-linear regression models were used to estimate projected food intake and crop yields based on recent historical data (1980-2014). Diet quality was estimated using the Healthy Eating Index-2015. Results: The US agricultural system can produce enough food to feed 146% of the population by 2030. A greater proportion of the population can be fed a high quality diet than a low quality diet (178% vs. 119%). To accommodate increased diet quality, substantial increases in cropland acreage would be needed for fruits (P<0.001), vegetables (P=0.002), legumes (P=0.002), and nuts (P=0.007); and decreased cropland acreage would be needed for grains (P=0.002) and sweeteners (P<0.001). Conclusions: The US can produce more than enough food to accommodate a shift toward a healthier diet pattern, but even moderate shifts in diet quality would require major transitions in cropland use. The success of this transition is dependent on several factors, like individuals’ ease of entry into the agricultural sector, producers’ ability to shift production to other crops, and modifications to the food supply chain.