Why Those Uneaten Fries and Side of Potatoes Are Bloating U.S. Food Waste

During the winter of 2024, Professor Gina Green and her research team undertook a messy assignment: picking through restaurants' trash in Washington, DC.

For three days, they sorted through half-eaten omelettes and lettuce slivers, pickles, fries, lime wedge carcasses and drizzly sauce containers. They analyzed every single order and any food that had been thrown out, and weighed the amount.

They wanted to find out what causes the most food waste: food that is thrown out before it reaches diners' plates or uneaten meals that end up in the trash?

"In the U.S., billions of dollars are wasted in the cultivation of food, the transportation of food and the consumption of food," said Green, the project lead and a professor in the Earth Commons. "It's a real global issue. I thought, we've got to focus holistically on what is that food waste? What goes into the trash bins?"

In a new paperby Green of Georgetown's Earth Commons Institute, graduate students, the Portion Balance Coalition, the Menus of Change University Research Collaborative(MCURC), and the food waste nonprofit ReFED, researchers found that food left on plates makes up 70% of total restaurant food waste.

That means those uneaten fries, potatoes and sides of fruit are fueling what amounts to a massive food waste challenge.

In 2023 alone, American restaurants and food service operators generated 12.7 million tons of surplus food, equating to 21 billion meals that were unsold or uneaten, according to a report by ReFed. That tallies up to $162 billion in annual waste-related costs, including food, packaging, labor and disposal.

If restaurants could adjust customers' portions, that could have real, tangible benefits on their bottom line and on the environment, the paper argues.

"This study reinforces what we've long believed at Georgetown's Portion Balance Coalition: portion strategy sits at the intersection of health, sustainability and business performance," said Laura Ferry, senior director of the coalition under Georgetown McDonough's Business for Impact, who worked on the paper. "When restaurants align portion structure with how people are actually eating today, they can reduce waste, control costs and maintain the guest experience."

Uneaten Meals Drive Food Waste

Clare Buckley (H'25) helps weigh food waste at a DC restaurant in 2025.

Over the course of a year, Green and her team of researchers and collaborators surveyed food service industry leaders and interviewed owners of fast casual restaurants in DC.

They found that most restaurants already track back-of-the-house waste, or food that is discarded before it's served due to over-ordering, spoilage or other preparation or operational issues.

But only 20% of those surveyed monitored what customers actually left on their plates, known as front-of-house waste.

"In our interviews with restaurants, they were like, 'We got back-of-house. We know we have to manage our back-of-house food supplies.' They have the software. They have the inventory, they understand their procurement,'" Green said. "But front-of-house is like, 'Who cares? You bought it. Right?'"

Green's team analyzed restaurant menus, conducted waste audits, and built a model to understand the amounts being thrown away and which menu items were and weren't selling. Here's what they found.

Over the course of a year, Green and her team of researchers and collaborators surveyed food service industry leaders and interviewed owners of fast casual restaurants in DC.

They found that most restaurants already track back-of-the-house waste, or food that is discarded before it's served due to over-ordering, spoilage or other preparation or operational issues.

But only 20% of those surveyed monitored what customers actually left on their plates, known as front-of-house waste.

"In our interviews with restaurants, they were like, 'We got back-of-house. We know we have to manage our back-of-house food supplies.' They have the software. They have the inventory, they understand their procurement,'" Green said. "But front-of-house is like, 'Who cares? You bought it. Right?'"

Green's team analyzed restaurant menus, conducted waste audits, and built a model to understand the amounts being thrown away and which menu items were and weren't selling. Here's what they found.

Starches and Sides Are Thrown Away the Most

Andrea Morante (G'25), an associate researcher in the School of Business, contributed to the project.

Bread and fries dominate the trash bin.

Starches like rice, potatoes and chips fill up plates and are often uneaten and tossed, Green's team found. As are sides of fruit, vegetables and dips.

"You want to fill your plates, so you look like you're getting good value for your meal," Green said. "So what's the easiest thing to fill your plate? French fries and bread or rice. We saw a lot of fruit wasted as well. There's a high cost to that, too, because fruit is more expensive than, say, potatoes. But potatoes are not cheap either."

These costs add up, Andrea Morante (G'25), a graduate student in the Business Analytics programin the School of Business who worked on the project, found. She built a model to show the results.

"We were able to say, 'On average for every potato sold, this is how much is wasted.' It's a lot of money that they are not effectively using for other things," she said. "It's helping businesses spend their money in a way that's more effective, while also helping the planet and providing more options for health-conscious consumers."

High-Calorie Meals Add Up

In auditing the restaurants' waste, Green's team found that large, high-calorie meals - 800-1,000+ calories - produced more waste than lighter, more customizable options (400-500 calories).

In a changing consumer landscape, especially as an increasing number of diners take GLP-1 medications and others want customizable portion sizes, restaurants can adjust, the paper notes.

"Most restaurant teams have yet to embrace portion customization for adult dinners, representing a missed opportunity to meet evolving consumer preferences and capture the growing market of health-conscious consumers," Green said.

Adjustable Portions Can Help Reduce Waste

In their research, 43% of the 70 major restaurant chains analyzed offered reduced or customizable portion options.

"Small portion options are not available in most restaurants beyond the kids' menus," said global health graduate student Shreyaa Venkat (H'24, G'25), who also worked on the study.

According to recent researchfrom ReFed, 59% of diners are more likely to visit restaurants that offer flexible portion options. Listing different options - like half-sized sandwiches, smaller entrees or optional sides - can help the environment and fatten restaurants' pocketbooks.

"The true cost of plate waste goes beyond just what's being scraped into the trash," said Abby Fammartino, MCURC co-chair. "There are labor and ingredient costs related to preparing, selling, serving and disposing the food left behind, for example. Customizable portion sizes offer a significant opportunity not just to reduce waste, but also to boost restaurants' bottom lines."

Expanding This Work in the Classroom

In 2022, Green visited a landfill in Samana, Dominican Republic, as part of her work as director of USAID's Clean Cities, Blue Oceans project.

Green hopes that their recommendations can help restaurants set food waste targets and track how much and which food items they're discarding. This work can spill over into helping the environment.

"Setting food waste reduction targets is critical," she said. "Nearly one-third of all food is wasted. So with restaurants, what does that mean? That means land use is a real issue. The water that it takes to grow the crops is a real issue. The transportation, the emissions are real issues. Methane is created from the organic waste that's thrown into the landfill. That all has an impact on the environment."

Green also hopes students can expand on their team's work through the Master's in Climate, Environment & Health program, where she serves as faculty director.

Venkat, who worked on the study while earning her master's in global health, found she was able to apply her classroom learnings to the research. She also brought her background as the founder and CEO of NEST4US, a nonprofit that partners with Panera Bread, Whole Foods and other restaurants to recover leftover food and deliver to communities facing food insecurity.

Shreyaa Venkat and her sister founded NEST4US, which has redistributed over 4 million pounds of surplus food to underserved communities. Photo courtesy of NEST4US.

"I've been able to bring my experiences of executing food rescues and seeing this waste into informing the recommendations and observations that I have done with this [paper]," she said. "And this was a great way for me to utilize the knowledge that I've learned from those experiences inside and outside the classroom."

She hopes that students can take this work even further to drive change in food insecurity.

"You just have to give them the opportunity to do so," she said.