Waste Not, Want Not: Reducing Food Waste Through Communal Sharing

CSE 440 Staff
5 min readDec 29, 2022

By Kate Wilkinson, Apollo Zhu, Isabella Nguyen, Derek Carlson

The Cost Of Food Waste

Pie chart of sources of food waste (4)

Have you ever made a big food purchase at the store and two weeks later you see it sitting there, in the fridge, expired? You are not alone. 44% of all food waste comes from residential households and expiring excess food contributes to this issue (4). Every year, the average American family throws out somewhere between $1,365 and $2,275 with at least 20% due to expiration labels. That is at least $273-$455 being wasted annually, on average, per American household (2)(3). The average American household also wastes, at minimum, between 0.33 metric tons to 0.99 metric tons of carbon dioxide per year due to expiration labels (1)(3).

How We Can Do Our Part In Our Community

Our solution to help alleviate these food expiration waste issues is the Waste Not, Want Not mobile app, focused on communal food sharing and food inventory/expiration management. Rather than letting food expire and go to waste, other people within the community may be looking for that exact ingredient. Waste Not, Want Not would provide options to conveniently share excess food and request ingredients for cooking. It would allow quick sharing to the community of soon-to-be expiring food by knowing the exact inventory of food within each household. For people living in high-density environments where they are within walking distance of their neighbors, Waste Not, Want Not could provide quick access to food and ingredients and cut down on expiring food waste while strengthening community connections between households.

Early Prototype and Testing

Scan, Inventory, Community, and Messages screens from our paper prototype.

We began testing our idea with an interactive paper prototype. This method allowed us the ability to quickly make changes and iterate our prototype as we uncovered problems during testing. By first using paper to test, we were able to focus on flow and functionality of our service rather than getting distracted by aesthetic details. We conducted multiple tests using this prototype. First was a heuristic evaluation based on Nielsen’s 10 heuristics for interaction design to find major flaws in our design. Second was a series of usability tests with members of our target user group to uncover issues more specific to our application.

The testing procedure helped to illuminate some of the problems in our design. We recognized through our paper prototype that we had mental models built up of how our application would work, and that users new to our service did not make the same connections as us and found navigation to be confusing. These results led us to be more conscious to provide users with the freedom to accomplish tasks in a variety of ways in our digital mockup. In our digital mockup we gave the user multiple routes to add items to their inventory and post food that were limited to a single pathway in our original design, which was poorly understood by users.

Bringing It All Together

The design solution settled on, based on the feedback from user research, is a mobile application focused on two key design aspects: food expiration awareness through in-app inventory and communal sharing of food, close-to-expiry or otherwise, to further manage waste and strengthen community connections. The inventory management is done through scanning groceries and importing them into the application’s inventory tab where it allows the users to keep track of expiring food. The communal sharing through requesting ingredients or posting offers of soon-to-be-expiring ingredients with a single tap within the inventory tab. Notifications for food requests from members of the community will be personalized to the user. This is done by notifying a user when an ingredient share request comes through, but only if they have the ingredient being requested within their current inventory.

Left: A quick scan to import groceries. Right: Inventory provides visibility of expiring food at a glance.
Left: Easily share, rather than waste, ingredients within the community. Right: Link up with communal requesters and givers alike.

We created a partially interactive digital mockup of our app within Figma, based on our paper prototype, to demonstrate our design’s functionality. After presenting the mockup to a panel of expert judges and fellow peers, we received feedback and altered the digital mockup accordingly. A common pain point for people using the mockups were the +/- buttons for changing item quantity in the inventory were too small. We increased the +/- button size in response to allow for a bigger touch area and increase accessibility on smaller phone screens. People testing our digital mockup also expressed safety concerns when exchanging food with other members of the community. We accommodated this concern by providing a user reliability scoring system that is visible when viewing posts made by other users. One can also check their profile to see what their own reliability rating is.

Left: View other user’s ratings on their community posts. Right: View your own rating on your profile.

The link to our interactive final prototype: https://www.figma.com/proto/yejum9Ko0lDdXETCWLktgE/Assignment-3d-Digital-Mockup

Towards A More Sustainable Future

Through our user research, we found that many people throw away food regularly, don’t interact with their neighbors as much as they would like to, and often find themselves missing ingredients when cooking at home. Waste Not, Want Not is a solution that empowers people to easily track their own food inventory, give away ingredients instead of letting them expire, and easily connect with the people living around them. Going forward, we envision a future where we rarely waste any of the ingredients in our fridges and share what we have with our local communities. Together, we’ll build closer bonds with our neighbors and a more sustainable relationship with the environment.


  1. Patil, S. (2020, June 16). Carbon footprint of Food Waste. Carbon Lyfe. Retrieved October 5, 2022, from https://www.carbonlyfe.com/blog/carbon-footprint-of-food-waste
  2. Dating game report — natural resources defense council. (n.d.). Retrieved October 5, 2022, from https://www.nrdc.org/sites/default/files/dating-game-report.pdf
  3. Commissioner, O. of the. (n.d.). Confused by date labels on packaged foods? U.S. Food and Drug Administration. Retrieved October 5, 2022, from https://www.fda.gov/consumers/consumer-updates/confused-date-labels-packaged-foods
  4. Understanding food waste. PartSelect.com. (n.d.). Retrieved November 9, 2022, from https://www.fix.com/blog/food-waste



CSE 440 Staff

University of Washington Computer Science, Intro to Human Computer Interaction