Data Vis Final Project

Food Waste in the United States

I cannot figure out how to publish to rPubs and get the shiny apps to run since rPubs requires static html documents. I tried publishing to shinyapps.io but I cannot get shinyapps to find my gifs and rendering directly in the document also breaks. So to view the shiny apps of my project you can go here https://grantbtzou.shinyapps.io/final_project_deployment/. Hopefully this is acceptable, otherwise I will figure out how to fix it for the final submission.

Introduction

As a kid, I often heard that the United States wastes an exorbitant amount of food. The number that I remember is 40%. When I first learned this, I couldn’t believe it. I thought about my meals and I knew that I did not leave 40% of my food on my plate. However, what I didn’t think about was all the other places where food is wasted, from places where food is consumed like restaurants, to places where food is sold like grocery stores, to the farms themselves. In this project, I aim to show where our food is being lost, what is causing the waste, and finally what potential solutions exist. To visualize this, I used ReFED’s food waste and solutions data.

To begin, I wanted to understand the scale of the problem. In the stacked bar chart below, you can see that we waste about 30% of our food supply in the United States every year. With the exception of 2020 when Covid began, we have also seen a steady increase in the amount of food wasted every year. This tracks with the 40% percent statistic I heard as a kid as depending on measuring methodology the numbers fluctuate.

Food Waste by Sector

However, knowing that we waste 30% of our food isn't enough. Just like me, I doubt you throw away 30% of the food on your plate at every meal. Where is this food actually being lost then? In the following graph we see food waste broken down by sector. The green bar shows how much of the waste could potentially have been diverted had all food waste solutions been implemented, which I will get to later in this project.

Here we can see that while the primary cause of food waste is coming from the residential sector, the residential sector makes up only a bit over 1/3 of total food waste in the United States. This would mean about 10% of our total food supply is lost in residential situations, including things like throwing away leftovers and expired food. This explains how on an individual level it may feel like we aren't wasting excessive amounts of food, but how we can still be wasting 1/3 of our total food supply as a country. The next largest sector of food waste is the agricultural sector, followed by manufacturing and food service, and finally retail. These other 4 sectors account for the remaining 2/3 of total food waste, showing that to effectively take on food waste in the United States we must look for solutions in all sectors.

Additionally, not all states face the same food waste challenges. In the following graphic, you can see the amount of waste each state generates and in what sectors. States with large populations generate more waste, and notably, California generates 13 million tons due to both its population and large agriculture industry.

What Causes Food Waste?

After understanding where the food waste was occurring, I wanted to know what was causing the waste. In the following treemap, you can explore the largest causes of food waste, filtered by year, sector, and broken down further within each cause group.

Trimmings and byproducts is by far the largest category of food waste in the United States. This is due to the fact that both the residential and manufacturing sectors produce significant amounts of this kind of waste and they are two of the largest sectors by waste generated. This is followed by food that is not harvested from the agricultural sector, which is the primary cause of food waste in the agricultural sector. The third major cause of food waste in the United States is excess, which is primarily a result of the food service and residential sectors.

Food Waste in Colleges

ReFED’s data is extremely detailed and breaks down each sector into sub sectors. For example, Food Service is broken down into 16 sub sectors such as Full Service Restaurant and Health Care, which themselves are broken down into sub sector categories like Mexican and Pizza, or Hospitals and Senior Living. It would take far too long and far too many visualizations to meaningfully analyze all of the categories, so instead I chose to focus on just one: Colleges and Universities. During my four years at UVA, I have always had at least 50 swipes per semester and frequently eat at the dining halls, so I have gotten an idea of the amount of food prepared, the amount left at the end of the night, and the amount thrown out at the dish return. Now I want to see how it is actually reflected in the data. First I wanted to see what the most wasted kinds of food were.

In this pareto chart, you can see that prepared foods are the most wasted food by an overwhelming majority. Prepared foods are anything that is served to clients in the food service industry, so unfortunately it doesn’t tell us much aside from the fact that Colleges and Universities are wasting a ton of food that they are trying to serve. Since the amount of non-prepared food wasted is so low, this indicates that most food is making it to being cooked and served, and not much is being thrown out beforehand, which is good.

Food Surplus Causes in Colleges and Universities

What causes food waste in Colleges and Universities? The following Pareto chart shows the cumulative causes of food surplus, and it is clear that excess food is the biggest cause of waste taking up nearly 80% of all causes.

This finding is consistent with both the previous finding about prepared foods and what I’ve seen in the dining halls. The dish return often has plates with tons of unfinished food getting thrown away, and at the end of each night there are often still trays of food unserved. This trend is unfortunately not limited to Colleges and Universities as excess is the leading cause of food waste in all of the Food Service industry.

Food Waste Solutions

Now let’s look at ways that we can prevent this food waste. ReFED has another data set which investigates the solutions that could be implemented along with their costs, benefits, and waste diverted. One of the first things that anyone looking to solve these issues will consider is how much does it cost to implement a solution? As it turns out, ReFED has calculated both the financial cost and the financial benefit of each solution. Most solutions actually end up having a positive net financial impact which is promising for making actual change, however, those who reap the financial benefit are not always those who have to pay the financial cost. This makes it challenging to implement even solutions with positive net financial benefit since not all stakeholders will benefit equally.

As the shiny app reveals, the solutions that provide the most financial benefit are Consumer Behavior Change Campaigns and Portion Sizes. These solutions have the highest gross benefits while also having extremely low costs. On the other side of the spectrum, the solutions that provide the greatest net financial cost are Centralized Composting, followed by Home Composting, and other forms of composting. While these solutions are extremely costly, we can’t fully evaluate them until we also learn how much waste they actually reduce. This is what the following Tableau scatter plot shows. The y axis shows waste diverted and the x axis the net financial benefit. The theoretical best solutions would be in the top right corner of the graph, but points at the extremes of both axes are worth examining.

As it turns out, while Centralized Composting would incur a net cost across stakeholders, it is the most effective solution measured by waste diverted at 11.7 million tons per year. The next two most effective solutions measured this way are also forms of composting being Centralized Anaerobic Digestion and Co-Digestion at Waste Water Treatment Plants. All of these solutions would result in a net cost to stakeholders but account for almost 20 million tons of potential waste diversion. These results show that a holistic approach is necessary to determine which solutions to prioritize when tackling food waste as each solution is impacting stakeholders and the environment differently.

Finally on the topic of stakeholders, let’s look at how implementing all solutions impacts stakeholders.

The biggest winners are by far the consumers, driven by consumer behavior changes. ReFED calculates consumer behavior changes to have 0 cost so the net benefit ends up being super high for consumers. Whether creating significant consumer behavior changes is possible without spending a penny is actually possible is up for debate, but ReFED is taking the optimistic estimate. Other stakeholders all see positive net financial benefit, although to much smaller degrees. ReFED also predicts that the government does not play a large role in spending or benefiting from food waste initiatives which may be a result of their methodology not factoring in the costs of pushing policy in congress. Regardless, ReFED’s estimate of the low stake of the government in food waste solutions may result in difficulties passing legislation that would make implementing many of the solutions possible.