Why Worry About Food Waste?

A few leaves of wilted lettuce. Half a dozen stale crackers. A bit of mouldy cheese. We’ve all had to throw out food that is no longer edible. We may bemoan the dollars and cents wasted–certainly a legitimate concern–but there is a bigger cost that some of us might not be aware of. The toll exacted on our environment and climate by food waste is considerable. While we, as consumers, are not the biggest contributors to the food waste problem, we can be a significant part of the solution. 

Consumption as a Cultural Imperative

Discussions of food waste can sometimes veer into guilt trips, and that is not my intention here. Food waste is a concrete problem with clear impacts, but it’s also a cultural issue, at least in North America, which is my direct experience. 

When shopping for food in this part of the world, we are confronted by abundance and encouraged to consume. Grocery stores are piled high with colourful displays of produce, dozens of freshly baked breads and treats, tempting displays of ready-made meals, and an endless variety of grocery products from cheese to crackers to cereal and everything in between. Pernicious “Buy More, Save More” and “BOGO” (buy one, get one free) offers compel us to buy more than we need. 

Every holiday–and even non-holiday occasions like the recent International Women’s Day, for which cakes can be ordered–is marketed through food, with messages beseeching us to provide not just a standard meal, but appetizers, salads, multiple side dishes, bread, main courses, and elaborate desserts; in short, more food than most of us could ever eat in two meals, never mind one. 

On top of all of this, the early days of the COVID-19 pandemic brought scarcities to which many of us in North America are unaccustomed, reinforcing the “stock up” and “why buy one when you can save on two” mentality that already dominated our thinking. 

Consumption has become a cultural imperative and it is a hard mindset to change. I get it. When I talk about food waste, I understand what many of us are up against. My goal is not to make anyone feel bad, but to convey the impact of food waste and provide solutions for gradual change in shopping habits. 

It’s April, the month we celebrate Earth Day, so I thought this would be a good time to talk about food waste through a series of blog posts. This is the first, and it is a long one, but I wanted to begin by defining why food waste is an issue. Subsequent posts will look more at actions we can all take to reduce the amount of food we throw away. 

The Scope of the Problem

Food waste is a multifaceted problem. Researchers look at it from a few different angles and the distinctions they use are important. 

First, there is the difference between food loss and food waste. Loss occurs during the production and retail phases of the food system–think of the fruit and vegetables in stores that are not purchased by consumers or spoilage during transportation. When looking at food waste in terms of household contributions, it is important to parse out the numbers referring to loss and focus instead on waste generated by consumers, as I have done here. (Not that food loss isn’t important, it’s just not what I’m looking at in this post.)

The other key definition is that of avoidable versus unavoidable waste. In households, unavoidable waste is the stuff we can’t eat: bones, egg shells, the rinds and stems of various fruits and vegetables. My focus in this article is the amount of avoidable household food waste. 

To keep the numbers relatable, I will focus on the country where I live–Canada–which offers a fairly typical representation of industrialized countries. Statistics vary widely in source and scope, but here are a few that help put the problem in perspective: 

  • Households in a small-scale 2019 study by the University of Guelph generated nearly 3 kg per week of avoidable food waste. (von Massow et al). 
  • In 2021, the UN reported an annual average of avoidable food waste of 79 kg per Canadian. (CTV News
  • Another report published in 2019 looked at the country as a whole, noting that households across Canada collectively generate 2.38 million tonnes per year of avoidable food waste. (Gooch et al, p. 26). 

So your mouldy cheese and wilted lettuce may not seem like a big deal, but when you consider all the mouldy cheese and wilted lettuce thrown away in this country, it adds up to a lot. 

As to why that matters, beyond the ultimate financial costs–$18 per week per household, according to the Guelph study–there is the issue of what happens after the food gets tossed.

The Environmental Impact of Food Waste  

When it comes to the environmental costs of food waste, one area of particular concern is greenhouse gas (GHG) emissions.* (Freshwater use is another issue, although not one that consumers can affect directly. Check the Further Reading section, below, for more information on that subject.) 

According to a 2021 report in Nature Food, food systems are responsible for one-third of global GHG emissions. (Crippa et al) The report breaks down the various sources of emissions, which Our World in Data converted to a graph, shown below. As we can see, the environmental costs of food loss and waste run, literally, from farm to table:

As consumers, there is not a lot of direct action we can take to affect the farm side of the equation, but we can do something about the 8.6% at the top of the graph: end-of-life, aka food waste.

Remember that 3 kg of food tossed by households each week? It creates 23.3 kg of carbon dioxide emissions, per household, per week. (von Massow) So if every household in Canada alone reduced their food waste even by half, the benefits would be significant. Extrapolate that globally, and you have major change. The 8.6% shown in the graph above could be reduced or even eliminated.

And the issue is urgent. The von Massow study referenced carbon dioxide emissions, but that is not the only–nor the most dangerous–greenhouse gas involved here. The fine print in the chart above mentions methane multiple times in the area of agricultural production, but methane is also produced by food rotting in landfills. A passage from a UC Davis blog explains:

“…decomposing food emits greenhouse gases, including the highly potent methane…As the EPA (Environmental Protection Agency) explains, the anaerobic conditions required for the production and release of methane are established in under a year after MSW [municipal solid waste] is dumped. Methane-producing bacteria begin to decompose the waste and generate methane. At approximately 28 times the global warming potential of carbon dioxide, methane is no doubt a potent greenhouse gas. However, after about 12 years, it’s broken down into water vapor and carbon dioxide. Given the glut of CO2 in our atmosphere, the emissions from food waste will stay there for centuries.” (Mitloehner)

You might be wondering, if you’re lucky enough to live in a city with a municipal organic waste program, whether that is a viable option for handling food waste. I’ve certainly thought so. If it goes in the green bin, it gets composted, right? Good for me, good for the environment. But, as the City of Toronto notes, municipal green bin programs are intended for unavoidable waste. Chucking all your food scraps is technically allowed, but it drives up costs and requires more resources for transporting and disposal. (City of Toronto) The ideal solution is to keep avoidable waste out of the waste stream as much as possible.

One of the best ways to reduce food waste is to commit to meal planning. With meal planning, you create a shopping list based on what you plan to cook, so you buy only what you need. Ideally, you will also include a plan for leftovers so little or nothing goes to waste. For most of us, meal planning is a massive change in habit, requiring us to become more mindful of the food we’re buying and how we plan to use it. Habit change can be daunting, but it can be done. It just takes a little time and practice. More on that in my next post. (Follow these links for the other posts in this series: Plan Ahead for Less Food Waste and Leftovers–Make a Plan to Use Them Up.)

* I am just scratching the surface by talking about GHG emissions from food in landfills. Emissions are an issue throughout the food system so any food waste also has to bear the weight of the production and distribution side. As an article in the Irish Times noted, “The problem is that we associate the value of food with the price of it. We see one carrot rotting in the fridge and we think, four cents, big deal. We don’t think of all the resources and energy and water that went into growing and transporting it and getting it to us. We don’t think of the environmental impact of that.”

I am writing this blog series in the knowledge that many families have financial constraints that limit their food choices and for whom food waste is not an option. If you would like to make a donation to help people living with food insecurity, here are a couple of organizations I have supported: Food Banks Canada and Breakfast Club of Canada. Your local food bank would also welcome donations of food or cash.

Food waste image: 225970143 © Joko Arif Fiyanto | Dreamstime.com


Cousins, Ben. (March, 2021) The average Canadian wastes 79 kilograms of food per year, the UN estimates. https://www.ctvnews.ca/climate-and-environment/the-average-canadian-wastes-79-kilograms-of-food-per-year-un-report-estimates-1.5333468

Crippa, M., Solazzo, E., Guizzardi D. et al.  (March 2021) Food systems are responsible for a third of global anthropogenic GHG emissions. Nature Food 2, p. 198-209. https://ecbpi.eu/wp-content/uploads/2021/03/Nature-food-systems-GHG-emissions-march-2021.pdf

Gooch, M., Bucknell, D., LaPlain, D., Dent, B., Whitehead, P., Felfel, A., Nikkel, L., Maguire, M. (2019). The Avoidable Crisis of Food Waste: Technical Report. Value Chain Management International and Second Harvest; Ontario, Canada. https://www.secondharvest.ca/getmedia/58c2527f-928a-4b6f-843a-c0a6b4d09692/The-Avoidable-Crisis-of-Food-Waste-Technical-Report.pdf

Mitloehner, Frank. (November 2020) The Carbon Impact of Food Waste: The Problem with What We’re NOT Eating. Clear Center, UC Davis.  https://clear.ucdavis.edu/blog/carbon-impact-food-waste-problem-what-were-not-eating

Ritchie, Hannah and Max Roser. (June 2021) Environmental Impacts of Food Production. Our World in Data. https://ourworldindata.org/environmental-impacts-of-food

Von Massow M, Parizeau K, Gallant M, Wickson M, Haines J, Ma DWL, Wallace A, Carroll N and Duncan AM (2019) Valuing the Multiple Impacts of Household Food Waste. Front. Nutr. 6:143. doi: 10.3389/fnut.2019.00143 https://www.frontiersin.org/articles/10.3389/fnut.2019.00143/full#B13

Further Reading

Food and Agriculture Organization. Food wastage: key facts and figures. https://www.fao.org/news/story/en/item/196402/icode/

Waterfootprint.org. Product Gallery. https://waterfootprint.org/en/resources/interactive-tools/product-gallery/

World Bank. Water in Agriculture. May 8, 2020. https://www.worldbank.org/en/topic/water-in-agriculture#1

World Wildlife Fund. Fight climate change by preventing food waste. https://www.worldwildlife.org/stories/fight-climate-change-by-preventing-food-waste

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