Smartphone app reveals patterns in how people choose and eat leftovers

Sep. 9, 2020
Example study image shows leftovers that were saved. Credit: Pennington Biomedical Research Center

Pilot study suggests potential areas of focus for food-waste reduction efforts

A new pilot study deepens understanding of behaviors surrounding consumption of leftovers in the U.S., suggesting that reducing meal sizes and making leftovers more appealing could help reduce food waste.

Brian Roe of Ohio State University, Columbus, and colleagues present these findings in the open-access journal PLOS ONE on September 9, 2020.

Food-waste reduction is a policy goal of the United Nations and of many national governments worldwide, due to its potential benefits in the realms of food security, sustainability, and economics. However, few studies have explored people’s behaviors surrounding household leftovers, limiting development of related strategies that could help reduce food waste.

To help deepen understanding of leftover behaviors, Roe and colleagues piloted a smartphone app designed for users to track which foods they ate that were leftovers saved from previous meals, as well as which unfinished foods they saved as leftovers for future consumption. The researchers analyzed data from 18 people living in or near Baton Rouge, Louisiana, who tracked their own leftover consumption for approximately one week.

The data showed that, of 1,177 total food items selected for consumption in the study, 12 percent were leftovers. Meanwhile, 24 percent of items left unfinished during meals were saved as leftovers. The most popular food types that were saved as leftovers were vegetables, cheeses, and meats, and the most popular time to select leftovers for a meal or snack was lunch on Mondays.

Statistical analysis also showed that participants were more likely to clean their plates when consuming non-leftover items, and they were more likely to leave food uneaten if they prepared larger meals. These findings suggest that efforts to reduce meal size and to make leftovers more appealing could help reduce food waste.

"Leftovers were less likely to be fully consumed than non-leftover items, and larger meals led to more uneaten food," said Roe. "Therefore, strategies to reduce meal size may be most effective in reducing food waste by limiting the creation of leftovers in the first place." 

This pilot study provides a first step towards deeper understanding of leftover behaviors in the U.S. Future research could help confirm and expand on these findings.