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A new working paper presented at the 2025 Agricultural and Applied Economics Association (AAEA) and Western Agricultural Economics Association (WAEA) Joint Annual Meeting is raising important questions for municipalities and organics recycling operators about how curbside composting programs may influence household food purchasing behavior. In Reducing Waste, Changing Habits: The Effect of U.S. Organics Diversion Programs on Food Purchases, the authors analyze whether residential organics diversion programs affect how much food households buy and, by extension, how much food they waste.
Using NielsenIQ Consumer Panel data from 2004 through early 2020, the researchers analyzed nearly three million individual monthly purchasing records from households in 295 U.S. cities with populations over 100,000. The study focuses on seven cities with curbside food waste collection programs, including two with mandatory separation requirements, San Francisco and Seattle, and five with voluntary programs such as Portland and Minneapolis. A “difference in differences” framework is used to compare food purchases before and after program implementation, relative to control cities without organics programs. A difference-in-differences framework compares what changed in cities that adopted food scrap collection programs to what changed over the same time period in similar cities that did not. In other words, it looks at how purchasing patterns shifted after a program launched and asks whether that shift was meaningfully different from normal trends happening elsewhere.
The author’s core finding is that voluntary curbside organics collection programs are associated with an average increase of about $3.58 in monthly household food expenditures. Mandatory programs add an additional $5.08 per month. Combined, mandatory organics collection programs are linked to an $8.66 increase in monthly food spending per household, or roughly 8.2% of average monthly food expenditures in 2020. These results are statistically significant and robust across specifications that account for household characteristics and time trends.
The increases are not uniform across food categories. Voluntary programs are associated with higher spending on fresh produce and deli items. Mandatory organics collection programs show additional increases in fresh produce and dairy purchases. An analysis on how collection programs are phased in suggests that voluntary program effects emerge gradually, becoming significant in the second and third years after implementation, while mandatory programs show impacts sooner.
The authors interpret these findings as evidence of a rebound effect. While diversion reduces landfill methane emissions, increased food purchasing implies greater upstream production, processing, and transportation. The paper estimates that, at scale, the additional food demand associated with mandatory programs could translate into a $26 billion increase in food loss and waste nationwide and nearly $714 million in added greenhouse gas damages annually.
This research echoes findings described by Brian Roe, Faculty Lead at The Ohio State University’s Food Waste Collaborative. Colleagues in cafeteria settings were told that food waste would be composted and subsequently left more food uneaten than those told it would go to landfill. Roe and his team labeled this behavior pattern “moral licensing.”
The study highlights the importance of pairing diversion infrastructure with upstream waste prevention strategies. Curbside composting clearly diverts material from landfill, but if it also changes purchasing behavior, total system impacts become more complex. The paper also notes that only about 10% of U.S. municipalities use pay as you throw pricing (PAYT), which may better align financial incentives with waste reduction goals.
It is important to note that the “difference in differences” approach of the study, which while widely used, relies on assumptions about parallel trends and may not capture individual household changes in buying habits before and after enrollment (e.g. cooking more at home after curbside collection programs roll out). Still, the analysis uses large scale purchasing data rather than self reported surveys, adding weight to its conclusions.
For municipalities expanding organics programs, the takeaway is not to retreat from diversion, but to design programs that integrate behavior change, pricing signals, and prevention messaging. Understanding how residents respond to new collection systems will be critical to maximizing climate benefits across the full food system.
