Carbon footprint tracking feature

Calculating and tracking the Co2 emissions of restaurant dishes to better educate customers about their takeaway choices.

User testing

Project context

Just Eat Hackathons take place once a year in which employees can take part in a three day long coding and brainstorming session which aim to try and either fix a problem, refine an existing issue, or come up with something completely new for any of Just Eat’s products.

To take part in the Just Eat Hackathon, you must first select the type of hack you are interested in working on. This could be your own idea, or select from one of the categories to be match-made into groups with a similar goal.

Our team consisted of six team members, focusing on a sustainability message for Just Eat customers across multiple touch-points.
Just Eat Takeaway
My Role
Hackathon Teammate, Researcher, Product + Interaction Designer, Motion/Video Designer and Graphic Designer
Product design Tools; Figma, Motion graphics and Video editing; After Effects, Team Brainstorming Software; Miro + Mural
3 days - March 2022

Our hack:

Our initial hack idea was to gamify the way in which customers use our products. Similar to a stamp-card reward system you can find in most cafés, our aim was to allow users to track the carbon emissions of the dishes they like to order. Then, in an effort to drive customer retention, we needed to develop incentives for those that selected options with a lower carbon footprint.

By tracking users carbon footprints, in theory, we could reach as far as inspiring change, by offering up alternatives to products with a large carbon footprint.
“Our hack, is to allow our users to track the carbon emissions of their dishes, and develop incentives for those choosing options with a lower carbon footprint.”

Judging criteria

Our concept would be judged on a variety of categories. The submission for the hack, needed to be in the form of a 3 minute video outlining the idea, research, development and execution, and should address all of the criteria below.

The winning hack would be built directly into the relevant product team’s road-map for the end of 2022, with scope to be shipped at the beginning of 2023.

The ability to think independently, uniquely and creatively


Evaluates the technical complexity to implement the design and will meet the given requirement


How many people does this benefit internally and/or externally?

Business value

How much value or efficiency will this drive for the business?

Prototype progress

How much progress have you made with your prototype?

Video effectiveness

How well does your video (3mins) explain your hack?

Market research

The initial research stage led us to look at both competitors outlooks on sustainability, but also to other types of food delivery services, such as Amazon, Hello Fresh, and OddBox. We found that, while these companies claimed to champion their food waste initiatives; such as incentives like tree planting, they were less interactive with their consumer when it came to granular details such as, food waste, packaging usage or Co2 emissions per user.

We had therefore believed that we had established a gap in the market. An idea like allowing the user to actively track their carbon footprint could prove very valuable in terms of sustainability and (in theory) the overall growth of the business.

Brainstorming and road-mapping

Once our independent research had been conducted, we created a Miro board in which to house our collective information as discuss each team mates findings. As our time was limited, we outlined the judging criteria and actioned a 10 minute session to allow us to gather as much qualitative data as possible for each.

We then refined the board into organised sections which helped to define our next action points for the hack.

With our action points clearly defined, we were able to scope out a road-map for the three-day stint of the hackathon. This allowed us to play on our strengths, gather resource and action each of the points as quickly and effectively as possible.

How we calculated the Carbon emissions of restaurant partner dishes across all of Just Eat’s platforms:


The research we had gathered from competitors spoke about broader ambitions, like business initiatives, and future goals rather than granular details such as the users impact on the planet. This was due to the information being relatively difficult to obtain because there can be nuances in the data as you start to dig deeper into the source.

Just Eat already has business initiatives in place such as using e-bikes for delivery and minimising plastic packaging from the restaurant partners. This data is easily obtained because Just Eat has full autonomy over how these issues are governed. However, from a food sourcing point of view, restaurant partners have more of a stake in how they provide their food to the customer, which means the data should be slightly more difficult to obtain.

Therefore, from a feasibility point of view, this was the trickiest to get right. If we were to accurately tag some of our dishes with some kind of Co2 statistic, we would need to find a reliable way of calculating the Co2 emissions per ingredient of our dishes.


Before the rise of 3rd party delivery services like Deliveroo or Uber Eats, Just Eat was previously a restaurant database which operated exclusively online. It meant that in order to legally house the information for restaurant partners, it was required by trading standards to file all nutritional information within each ingredient, of each dish produced by that restaurant.

This means that Just Eat is in the unique position of possessing a Food Catalogue Team which houses and monitors data for all ingredients contained within restaurant partner dishes, which, in term, are now provided across all Just Eat products.

This also means that the teams can provide ingredient predictions around the varying cultivation methods used to obtain certain ingredients. As well as this, we had to take the average weight of each ingredient into consideration to accurately address the Co2 emissions of the shipment process. This then allowed us to take ingredient origins into consideration and tag Co2 emissions accordingly, based on the location of the user.

Using this data, we had therefore established a way to pin-point, with a relative degree of accuracy, how much Co2 was needed to produce an ingredient and subsequently, the dish.

User personas

Now that we had established a quantifiable way of collecting the data, we needed to create user personas which would help to determine top level use-cases within the product. Using this type of technique without any user research might seem slightly redundant, but when referring back to the hackathon judgment criteria, this relates directly to Impact. We needed something tangible to make a start on the rest of the project channels and so, we felt that creating a couple of user personas could be a relatively quick way of doing so. Even if the output is slightly biased.

We developed three user personas, all with varying levels of product knowledge, environment consciousness and takeaway experience.


From the User Personas, we were able to define three separate user flows to meet the needs of our three different user types. Before creating the high fidelity prototypes for each, we spent some time mapping out each user flow using low fidelity wireframes. This was a relatively quick turn around and proved invaluable when it came to the design stage of the process.

We characterised our customer needs into three user flows:

User flow 1:
Create awareness

To create awareness around the programme, we designed a flow to showcase more information, incentives and user interactivity. Restaurants are tagged as ‘Low Co2’, which is highlighted within the homepage, and a tap-through page is shown. From here, the user is shown more information about what they can do to offset their Carbon Footprint.

User flow 2:
Search and filter

For users that are more conscious about the environment, we designed a user flow that would allow the user to utilise the Search and Filter functions that already exists within the product. This enables dishes and restaurants tagged as ‘Low Co2’ to be shown first in the search criteria.

User flow 3:
Inspiring change

Some restaurants will not show any eco-friendly dishes because of the nature of their food type or source. In an effort to utilise this feature, without upsetting any of these partners - we designed an option at the ‘Checkout’ stage of the user journey. This option allows customers to swap out their dish choice with a more sustainable food/ingredient product.

Branding and development

With our use cases addressed and wireframes completed, we were able to start to build out the branding and iconography into a working prototype. Just Eat’s aesthetic has just undergone a global re-brand, so we took these elements into account when addressing things like, colour, icons, type and illustration.

We opted to use a green colour for all branding of our hack for a couple of reasons: firstly, we found through our research that any kind of environment issues, stats, or changes within our competitor research, often used some kind of shade of green. We found that this is because green tends to fit the users mental model for what is either, vegan, vegetarian or environmentally conscious - so we found that this would be a perfect fit for our branding within the product.

Secondly, throughout Just Eat’s rebrand, there was no use of the colour green at all within the guidelines. This meant that our product hack would be able to stand out amongst the rest of the branding and allow our Co2 programme to be accessed by the user more easily.

Project submission

With our research branding complete and our prototypes ready, we used the little time we had left to gather all of our research, discussion points, stats and designs and start to form the storyboarding slides for our submission video. Each team member summarised in one or two slides, their findings and research on their area of focus. We then drafted notes under each which helped inform the script for the video.

Once we had all of our information ready for the entire project, we went through several refinement stages to highlight the most important and relevant points. This also helped to cut down the overall time of the submission and leave as much time to showcase the working prototypes, which would take up around 30% of the video time.

Within our video submission, we were able to show the following:

We addressed the problem and outlined the potential business value in solving it. Showed how we were able to calculate a formula to allow this idea to scale. Developed a working prototype to show our idea in action. And showed the next steps from a technical standpoint which would allow accuracy to build on user trust.

Hackathon outcome

Our hack was a runner up to another couple of clever initiatives, but was granted special consideration as a mid/long term project for Q4/Q1 2023 with scope to be design and implement by Q2/3 2023.

Since my departure from the company, Just Eat Takeaway had partnered with My Emissions to take our hack and develop it into a working feature within all Just Eat products. The designs and technical implementation had been changed in order to be scaled across the business effectively. The feature uses 'Carbon Labelling' and rates dishes based on 5 levels. The formula for assessing the dishes carbon footprint remains the same as our original hypothesis, but categorises the dishes into ratings from A to E based on their impact to source, make and deliver to our customers.

You can read the full LinkedIn article or head to Just Eat's landing page which talks through the process in much more depth.