A Review of Household Food Waste Generation during the COVID-19 Pandemic

Abstract

The COVID-19 pandemic may have impacted the quantity and composition of household food waste generation in parallel with recent changes to food behaviors. A literature review was undertaken to determine the state of household food wasting during pandemic circumstances. Forty-one articles that reported on household food waste generation during COVID-19 were identified. Most of these studies relied on self-reported recall of food wasting behavior (n = 35), primarily collected through surveys. The average total amount of household food waste generated during COVID-19 was 0.91 kg per capita per week. Average avoidable food waste generation was 0.40 kg per capita per week and average unavoidable food waste generation was 0.51 kg per capita per week. Fruit and vegetables were the most wasted types of food. Only five studies reported statistically significant changes (actual or perceived) to household food waste generation during COVID-19. These results indicate a possible decrease in total, perceived food waste generation during pandemic circumstances, with a possible increase in the actual generation of unavoidable food waste. Further research is needed to adequately determine the impact of the pandemic on household food waste generation, as the findings summarized in this review vary substantially and statistically significant results are limited.

1. Introduction

One-third of the food grown and produced globally is lost or wasted each year [1]; the majority (61%) of which is thought to be thrown away at the household-level [2]. Wasting food contributes to climate change, especially when it decomposes in an anaerobic landfill environment. Beyond landfill emissions, when food is wasted, all the embedded energy used to grow, harvest, transport, and store that food is also wasted [3,4]. Economically, household food waste results in unnecessary, and often preventable, increased personal expenses [5], and places logistical and financial burdens on municipal waste management facilities. Food waste also often signifies poor food distribution systems and works against eliminating food insecurity. As such, the United Nations’ Sustainable Development Goal (SDG) 12.3 aims to halve per capita global food waste by 2030. With only eight years remaining to achieve this goal, it is critical to consider how the COVID-19 pandemic may have impacted the quantity and composition of household food waste.

The COVID-19 pandemic has transformed many aspects of life, and, consequently, may have also altered household food wasting behaviors. Behaviors resulting in food waste are often more closely related to household food provisioning than waste management [6]. During the pandemic, there have been reported decreases in food shopping frequency [7,8] and reported increases to the amount of food purchased per food shopping trip [9,10]. These behavioral changes are probably a consequence of inconveniences introduced by regional COVID-19 lockdowns and temporary public health measures, such as having to wait in line to enter brick-and-mortar stores due to reduced indoor capacities, and/or health and safety concerns regarding the risk of community-spread and the transmission of the virus in indoor spaces.

Further, COVID-19 has resulted in changes to how some consumers prefer to shop for food. Several studies have found that there have been increases in online food shopping during the pandemic [8,10,11]. There have also been reported increases to local food purchases [7]. These increases may be related to community movements aimed at supporting local food vendors in a time of economic hardship and uncertainty.

With more people working and learning from home, there have been notable changes to at-home food preparation and management. The number of meals prepared and eaten at home has increased during the pandemic [7,10,11]. There also appears to be an increase in the use of at-home food management techniques, such as pre-planning food shopping trips and eating leftovers more often [8,10]. In parallel with recent changes to food shopping, management, and consumption behaviors, it is possible that COVID-19 may have also impacted the quantity and composition of household food waste generation.

The purpose of this review is to determine the state of household food waste during the COVID-19 pandemic. To halve per capita global food waste by 2030, policies and programs that effectively reduce household food waste generation are urgently needed. An adequate and reliable understanding of the quantity and composition of household food waste during COVID-19 is necessary to develop effective approaches to reduce household food waste in a post-pandemic world. As such, the research questions explored in this review include:

(1)

What is the quantity and composition of household food waste during the COVID-19 pandemic?

(2)

Has there been a change in the quantity and/or composition of household food waste since the onset of the pandemic?

2. Materials and Methods

A review was undertaken to address a new knowledge gap prompted by the outbreak of COVID-19 and respond to academic and policy demand. This review considered articles that reported on household food waste generation during the COVID-19 pandemic. This incorporates the generation of total food waste, avoidable food waste (i.e., food that was at one time edible), unavoidable food waste (i.e., food that was never edible, such as coffee grounds), and/or possibly avoidable food waste (i.e., food that some people consider edible while others do not, such as potato peels) at the household-level. Empirical studies published between March 2020 and September 2022 were included, because the World Health Organization [12] declared the COVID-19 outbreak as a global pandemic on 11 March 2020.

The context of this review is global, so no inclusion or exclusion criteria were set for the geographic region of study; however, the search was limited to articles published in English. While it is typical for reviews to exclude studies based on the quality of methodology [13], no such evaluation was applied in this review. Due to the limited number of articles published within the first two years of the COVID-19 pandemic, the decision not to exclude articles based on methodology allowed for the most comprehensive assessment of household food waste generation during pandemic circumstances. Both quantitative and qualitative studies were included, and no inclusion or exclusion criteria were set for the food waste measurement methodology utilized. Keyword strings were identified around the themes of household food waste generation and COVID-19. To select keyword strings, the reviewers considered keywords that had previously been used in other food waste-related and pandemic-related review studies. These keyword strings were used to search titles, abstracts, and keywords on two comprehensive bibliographic databases (Scopus and Web of Science) on 7 April 2022 (

Table 1. The search term strategy employed in the review.

Search Number	Search Terms
#1	TITLE-ABS-KEY ((‘food wast*’) OR (‘organic wast*’))
#2	TITLE-ABS-KEY ((‘house*’) OR (‘home*’) OR (‘resident*’) OR (‘consumer’))
#3	TITLE-ABS-KEY ((‘COVID’) OR (‘COVID-19′) OR (‘coronavirus’) OR (‘SARS-CoV-2′) OR (‘pandemic’) or (‘lockdown’) OR (‘outbreak’))
	#1 AND #2 AND #3

Note: “TITLE-ABS-KEY” refers to titles, abstracts, and keywords.

). An updated search was conducted on 21 September 2022, to identify more recent studies. The search yielded 343 articles, which were then imported to the software Covidence (Veritas Health Innovation) for managing data collection and extraction.

Two reviewers screened titles and abstracts against the inclusion and exclusion criteria, and then articles were further assessed through full-text screening (Figure 1). The following data were extracted from eligible articles (n = 41): author(s), year of publication, geographical location of the study, methodology, when (month/year) data were collected, sample size, quantity and composition of food waste generated during COVID-19, and changes in food waste quantities and/or composition during COVID-19. When necessary, a reviewer emailed corresponding authors to ask for further data; however, many of these emails went unanswered.

3. Results and Discussion

The majority (59%) of the studies included in this review were published in 2021, followed by 2022 (24%), and 2020 (17%). Articles were published in 23 unique journals, including a special section on food loss and waste during COVID-19 in Socio-Economic Planning Sciences (n = 8), Sustainability (n = 7), and British Food Journal (n = 3). Most studies were conducted in Europe (n = 17) or North America (n = 8), followed by Asia (n = 5), South America (n = 3), Africa (n = 3), and Oceania (n = 1). A variety of food waste measurement methodologies were used. Thirty-five studies relied on self-reported recall of food wasting behavior, four followed a direct measurement approach, and two were studies of secondary data.

3.1. Direct Measurement Studies

Only four of the forty-one articles included in this review followed a direct measurement approach (

Table 2. Food waste composition studies measuring the quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of DataCollection	Quantity and Composition of Food Waste (Kilogram per Capita per Week)	Change in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[15]	London, ON, Canada	100 households	June 2020	Total food waste: 0.96	Not reported
				Avoidable food waste: 0.49
				Fruit and vegetables: 0.16
				Bread and bakery: 0.10
				Other food: 0.10
				Dried food: 0.06
				Meat and fish: 0.05
				Dairy: 0.02
				Unavoidable food waste: 0.47
				Fruit and vegetables: 0.32
				Other food: 0.09
				Meat and fish: 0.07
[16]	London, ON, Canada	99 households	June 2020	Total food waste: 0.97	Total food waste: +22.5%
				Avoidable food waste: 0.53	Avoidable food waste: +0.4%
				Fruit and vegetables: 0.19	Fruit and vegetables: −21.0%
				Bread and bakery: 0.09	Bread and bakery: −14.7%
				Other food: 0.10	Other food: +227.5% **
				Dried food: 0.06	Dried food: −17.6%
				Meat and fish: 0.06	Meat and fish: +4.4%
				Dairy: 0.02	Dairy: +25.6%
				Unavoidable food waste: 0.45	Unavoidable food waste: +65.5% **
				Fruit and vegetables: 0.32	Fruit and vegetables: +78.1% **
				Other food: 0.07	Other food: +83.9% *
				Meat and fish: 0.06	Meat and fish: +12.8%
[17]	Guelph, ON, Canada	19 households	July to August 2020	Total food waste: 1.08	Total food waste: +0.4%
				Avoidable food waste: 0.47	Avoidable food waste: −32%
				Fruit and vegetables: 0.29	Fruit and vegetables: −5%
				Other: 0.18	Other: −54% *
				Unavoidable food waste: 0.61	Unavoidable food waste: +58% **
				Fruit and vegetables: 0.43	Fruit and vegetables: +48% *
				Other: 0.19	Other: +89% **
[18]	Brno, Czech Republic	900 households	May to June 2020	Avoidable food waste: 0.44	Avoidable food waste: decreased

* p < 0.05, ** p < 0.01.

). Direct measurement studies require a field team to collect, weigh, and sort curbside waste samples from study households to determine the amount and composition of food waste generated by research participants [14]. Everitt et al. [15,16] and Laila et al. [17] used similar, direct measurement methodologies to measure the quantity and composition of household food waste in two Canadian cities (London, Ontario and Guelph, Ontario) that are 120 km apart from one another. While Everitt et al. [15,16] sampled a greater number of households (n_a = 100, n_b = 99) in London, Laila et al. [17] collected food waste measurements from their smaller sample (n = 19) in Guelph four times and averaged the results over a longer sampling period to improve accuracy. Households in London and Guelph generated similar quantities of total (0.96–1.08 kg/capita/week), avoidable (0.47–0.49 kg/capita/week), and unavoidable (0.45–0.61 kg/capita/week) food waste between June and August 2020. Unavoidable fruit and vegetables and avoidable fruit and vegetables were the most wasted types of food in all three studies, respectively. The 4% (n = 0.02 kg) difference in the generation of avoidable food waste and the 13% (n = 0.12 kg) difference in the generation of total food waste suggest that there may be regional consistencies in household food wasting.

Kubíčková et al. [18] followed a considerably different direct measurement methodology, in which only a small sub-sample of waste was analyzed from the total garbage sample collected from 900 study households. The study also only reported on avoidable food waste generation. Despite these methodological differences, within the first six months of the COVID-19 pandemic, the generation of avoidable food waste in Brno, Czech Republic (0.44 kg/capita/week) was similar to the quantity of avoidable food waste generated in the Canadian cities (0.47–0.49 kg/capita/week). Between Brno and London, the difference in avoidable food waste generation was 11% (n = 0.05 kg), and between Brno and Guelph, the difference was only 7% (n = 0.03 kg). However, it is unknown if this similarity in avoidable food waste generation was present prior to the pandemic, whether pandemic circumstances are responsible for this similarity, or how methodological differences may have impacted the results.

Everitt et al. [11], Laila et al. [17], and Kubíčková et al. [18] reported changes to household food waste generation by comparing the amount of food wasted by the same study households before and during pandemic circumstances. While no significant changes to the generation of total avoidable food waste were reported in London, there was a significant increase in avoidable ‘other food’ (p < 0.01) during the pandemic [16]. In Guelph, there was no significant change in the generation of total avoidable food waste; however, there was a significant decrease in avoidable ‘other food’ (p < 0.05) during COVID-19 compared to before the outbreak [17]. In Brno, it was reported that the generation of total avoidable food waste decreased during the pandemic compared to before COVID-19 [18]. However, this finding was not supported by any statistical test to determine if the difference was significant. In London (p < 0.01) and Guelph (p < 0.01) total unavoidable food waste significantly increased during the pandemic, including significant increases in the generation of unavoidable fruit and vegetables (London: p < 0.01), Guelph: p < 0.05) and unavoidable ‘other food’ (London and Guelph: p < 0.01) [16,17]. Both direct measurement studies with statistically significant results observed no significant change to the generation of total food waste, suggesting that COVID-19 has probably not had a noteworthy impact on total household food waste generation. Because the generation of total avoidable food waste has remained unchanged, the pandemic has also probably not acted as a natural intervention to reduce household food wasting. However, it appears that COVID-19 has had a considerable impact on unavoidable household food waste generation. The significant increase in unavoidable food waste indicates a possible reallocation of waste from places that were inaccessible or less frequented during the pandemic (e.g., places of employment) to the household level.

3.2. Studies Using Self-Reported Recall Data

Two of the articles included in this review used a food diary methodology to measure household food waste generated during COVID-19 (

Table 3. Food diary studies measuring the perceived quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of Data Collection	Perceived Quantity and Composition of Food Waste (Kilograms per Capita per Week)	Perceived Changes in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[19]	Italy	15 households	March to May 2020	Total food waste: 0.63	Not reported
				Vegetables and legumes: 0.26
				Fruit: 0.20
				Fish and fish products: 0.07
				Meat and meat products: 0.05
				Milk and dairy products: 0.03
				Pasta and rice: 0.01
				Bread and bakery products: 0.01
[25]	Arequipa, Peru	44 participants	September to October 2020	Total organic waste: 1.34	Total organic waste: +17% 1
				Food scraps and garden waste: 0.93
				Leftover food and stews: 0.41

¹ Not a direct comparison within the same sample of participants.

). Within the first three months of the pandemic, households in Amicarelli and Bux’s [19] Italian sample (n = 15) self-reported a generation of 0.63 kg of total food waste per capita per week. This is considerably less than the direct measurements collected a month later in London and Guelph, Canada (0.96–1.08 kg/capita/week) [15,16,17]. While there may be substantial regional differences in household food wasting between Italy and Canada, the variation in results may also be partially due to the expected presence of social desirability bias in the Italian study. Because wasting food has been found to be associated with feelings of guilt, anxiety, disgust, and shame [11,20,21], the deliberate underreporting of food waste quantities often occurs in studies of self-reported recall data [22]. Self-reported household food waste generation has been found to be underreported by 20% [23] to 40% [24] in food diary studies compared to direct measurement studies. The difference in food waste generation between London, Canada and Italy was 34% (n = 0.33 kg), and between Guelph, Canada and Italy, the difference was 42% (n = 0.45 kg). Like the three Canadian samples, fruit and vegetables were also the most wasted types of food in the Italian sample.

Requena-Sanchez et al. [25] measured household food waste in Arequipa, Peru later in the pandemic, in September and October 2020. Participants self-reported the generation of 1.34 kg of organic waste per capita per week [25]; however, this value also includes garden waste—an organic, but non-food waste item. As food waste was not reported on its own in Requena-Sanchez et al. [25], it is not possible to directly compare the results of the two food diary studies. A comparison within the sample geographic region, but not the same participant sample, suggested that Peruvian household food waste increased during the pandemic by approximately 17% compared to measurements collected in 2019 [25]. However, this finding was not supported by any statistical tests for differences.

Most of the articles (n = 33) included in this review used a survey methodology to explore household food wasting during the pandemic (Table 4). Surveys predominantly asked respondents to report on food behaviors, such as food shopping frequency and food preparation routines. It was typical for surveys to only contain a single question about food waste generation. Many of these questions asked respondents to recall the amount of food they wasted before and during the pandemic, and report perceived changes on a 5-point Likert scale (e.g., decreased a lot, decreased a little, no change, increased a little, increased a lot). Food waste was rarely defined in survey studies. When no definition was available, the reviewers assumed that the term ‘food waste’ was used to describe all wasted food, including avoidable and unavoidable components.

The perceived quantity of food waste generated during COVID-19 was only reported in a few survey-based, recall studies. In the United Kingdom, respondents self-reported wasting 9% of unprepared and uneaten purchased foods, and 7% of cooked food [26]. Vargas-Lopez et al. [27] used a similar methodology in Mexico. Respondents self-reported percentages of purchased food wasted, rather than eaten, for various food categories. A total of 21% percent of purchased vegetables were perceived to be wasted, followed by 19% of purchased fruit, and 15% of purchased tortilla, rice, cereals, and pasta [27]. The usefulness of studies that report food waste generation as a percentage of food discarded, rather than eaten, is limited due to the inability to accurately analyze changes over time or across regions. Vasko et al. [28] asked survey respondents in Montenegro to quantify their avoidable food waste generation during COVID-19 using ambiguous response options, including “very little” (38% of respondents) and “a reasonable amount” (27% of respondents). The usefulness of quantifying the generation of food waste without clearly defined units of measurements is limited, as ambiguous survey response options are susceptible to independent interpretation.

In Serbia and North Macedonia, most research participants (46% and 52%, respectively) claimed not to have generated any avoidable food waste during COVID-19 [29,30]. These results should be interpreted with caution as they are probably a consequence of social desirability bias. Of the Serbian participants who self-reported avoidable food waste, 22% indicated that they wasted less than 0.25 kg per week and 21% indicated that they wasted between 0.25 and 0.5 kg per week [29]. Similarly, 23% percent of respondents in North Macedonia self-reported wasting less than 0.25 kg of avoidable food waste per week, followed by 18% who wasted between 0.25 and 0.5 kg per week [30]. While the results from these two studies are limited by their chosen methodology, it appears that there may be regional consistencies in household food wasting within these two European countries.

Most respondents (73%) in Music et al.’s [31] Canadian study perceived they wasted less than two kilograms of avoidable food waste per week. This finding generally aligns with the average generation of avoidable food waste in Everitt et al.’s [15,16] and Laila et al.’s [17] direct measurement studies; however, comparability is limited by the measurement scale used in Music et al.’s [31] survey. Respondents were asked to self-report their weekly avoidable food waste generation by selecting one of the following response options: less than two kilograms, two to four kilograms, four to six kilograms, six to eight kilograms, or more than eight kilograms [31]. Only 2% of respondents perceived they generated more than six kilograms of avoidable food waste per week, despite this quantity accounting for one-third of Music et al.’s [31] response options. The rationale behind the chosen measurement scale is unclear, as response options do not appear to be consistent with pre-COVID-19 food waste measurements in Canada (see Parizeau et al. [21], van der Werf et al. [32], and von Massow et al. [33]). The use of a scale with more response options for lower food waste generators, rather than multiple response options for abnormally high food waste generators, would have increased the comparability of these results to other studies in Canada and beyond.

Vidal-Mones et al. [34] reported that 0.09 kg of perceived avoidable food waste was generated per capita per week in Spain. It is likely that this self-reported quantity is grossly underreported as it is substantially lower than all the direct measurements collected during COVID-19 (0.44–0.53 kg/capita/week). Between Spain and Canada, differences in avoidable food waste generation ranged from 80% (n = 0.35 kg) to 83% (n = 0.44 kg). Researchers collecting self-reported recall data through surveys often assume that participants represent entire households, or researchers use proxy reporting. Assuming that the responses provided by a single person are representative of the food wasting behaviors of all household members may lead to inaccurate and biased data [35], especially when the respondent is not the household member primarily responsible for the household’s ‘foodwork’. Proxy reporting is prone to similar data limitations, particularly because wasting food is often an ‘out of sight, out of mind’ type of behavior. This makes recalling your own food waste generation difficult, let alone someone else’s. Vidal-Mones et al.’s [34] unusually low findings may be a consequence of methodological limitations.

A mixed methods approach was used to determine the quantity of organic waste (i.e., food waste, yard waste, and wasted wood) generated in Zimbabwe [36]. It was estimated that, on average, households generated 35.2 kg of organic waste per week during the pandemic [36]; however, it is not known what formula and combination of data were used to generate this estimation. As food waste was not reported on its own in Dzawanda and Moyo [36], it is also not possible to directly compare these results with other studies.

The perceived composition of food waste generated during COVID-19 was also only reported in a few survey-based, recall studies. Consistent with pre-pandemic results [33,37], the types of food most wasted during COVID-19 included fruit, vegetables, and bread and bakery products [26,27,28,38,39,40,41,42]. Meat and meat products appear to be the least likely type of food to be thrown away [26,39,40,41], except in the case of one Greek study that found cold meats to be a frequently wasted food item [43]. The lack of an internationally recognized, standard food waste classification scheme limits the ability for composition results to be compared across studies. The creation of a standardized food waste reporting guide would increase the feasibility of conducting longitudinal studies that aim to analyze food waste generation over time and across geographies.

Table 4. Survey-based, recall studies measuring the perceived quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of Data Collection	Perceived Quantity and Composition of Food Waste	Perceived Changes in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[26]	United Kingdom	473 survey respondents	March 2020	Avoidable food waste: respondents wasted 9% of purchased waste (i.e., purchased and thrown away uneaten) and 7% of cooked waste (e.g., cooked before being thrown away). The most wasted types of purchased waste were green leafy vegetables, carrots, potatoes, and sliced bread. The least wasted types of purchased waste were beef and chicken. The most wasted types of cooked waste were polenta, green leafy vegetables, and white rice. The least wasted types of cooked waste were beef, chicken, and bread.	Not reported
[27]	Mexico	525 survey respondents	December 2020 to January 2021	Total food waste: Fruit: 19% wasted Vegetables: 21% wasted Beef, chicken, and pork products: 10% wasted Fish and shellfish: 4% wasted Milk, yogurt, and dairy products: 10% wasted Eggs and cheese: 6% wasted Tortilla, rice, cereals, and pasta: 15% wasted Bread and pizza: 7% wasted Seasonings: 4% wasted Desserts: 5% wasted	Total food waste: −2% **
[28]	Montenegro	514 survey respondents	May to June 2020	Avoidable food waste: the most wasted types of food were bread and bakery products, followed by fruit and vegetables. Almost none: 17% of respondents Very little: 38% of respondents Reasonable amount: 27% of respondents More than I should: 11% of respondents Much more: 7% of respondents	Avoidable food waste: Decrease: 5% of respondents No change: 74% of respondents Increase: 21% of respondents
[29]	Serbia	1212 survey respondents	May to June 2020	Avoidable food waste (kilograms/week): No wasted food: 46% of respondents <0.25: 22% of respondents 0.25 to 0.5: 21% of respondents 0.5 to 1: 7% of respondents 1 to 2: 2% of respondents >2: 1% of respondents	Avoidable food waste: Decrease: 8% of respondents No change: 63% of respondents Increase: 30% of respondents
[30]	North Macedonia	754 survey respondents	May to June 2020	Avoidable food waste (kilograms/week): No wasted food: 52% of respondents <0.25: 23% of respondents 0.25 to 0.5: 18% of respondents 0.5 to 1: 5% of respondents 1 to 2: 1% of respondents >2: 1% of respondents	Avoidable food waste: Decrease: 5% of respondents No change: 57% of respondents Increase: 38% of respondents
[31]	Canada	8272 survey respondents	August 2020	Avoidable food waste (kilograms/week): 0: 17% of respondents *** <2: 73% of respondents 2 to 4: 20% of respondents 4 to 6: 6% of respondents 6 to 8: 1% of respondents >8: 1% of respondents	Avoidable food waste (kilograms/week): <2: 80% of respondents 2 to 4: 15% of respondents 4 to 6: 5% of respondents 6 to 8: 1% of respondents >8: 1% of respondents
[34]	Spain	6293 survey respondents	May to June 2020	Avoidable food waste: 0.09 kg per capita per week	Avoidable food waste: Decrease or no change: 96% of respondents Increase: 3% of respondents Not applicable: 2% of respondents
[36]	Gweru City, Zimbabwe	169 survey respondents	2021	Organic waste: 35.2 kg per household per week	Not reported
[38]	Turkey	1098 survey respondents	March to June 2020	Avoidable food waste: the most wasted types of food were bakery products, leftover foods, and fruit and vegetables. The least wasted types of food were milk and dairy products, beverages, cooking oil and related products, and legumes.	Avoidable food waste: Fresh fruit and vegetables: decrease *** White meat and products: decrease *** Milk and milk products: decrease *** Packaged take-home foods: decrease *** Bread and flour products: decrease *** Legumes: decrease *** Leftover foods: decrease ***
[39]	Tunisia	284 survey respondents	March to April 2020	Avoidable food waste: the most wasted types of avoidable food were bakery products, vegetables, and fruit. The least wasted types of avoidable food were fish and seafood, meat and meat products, and pulses and oilseeds.	Not reported
[40]	Portugal, Italy, Germany, Brazil, Estonia, United States, Australia, Canada, Singapore, United Kingdom, Denmark, Spain, Poland, Finland, Bangladesh, Argentina, Chile, Ireland, New Zealand, Japan, Malaysia, Indonesia, and Vietnam	204 survey respondents	August to November 2020	Total food waste: the most wasted types of food were fruit and vegetables, meat, dairy products, bread, and fish and seafood. The least wasted types of food were ready-made meals, canned food, milk, cereal and grain products, and potatoes.	Total food waste: Decrease: 15% of respondents No change: 37% of respondents Increase: 45% of respondents Do not know: 3% of respondents
[41]	Peru	418 survey respondents	May 2020	Avoidable food waste: vegetables, fruit, and roots and tubers were the most wasted types of food. No wasted food: 63% of respondents Some wasted food: 35% of respondents	Not reported
[42]	Poland	500 survey respondents	March to April 2021	Total food waste: The most wasted types of food were fruit, vegetables, bread, and dairy products	Not reported
[43]	Greece	2205 survey respondents	April 2020	Total food waste: The most wasted types of food were dairy products, fruit and vegetables, and cold meat. No wasted food: 22% of respondents	Not reported
[44]	India and United States	590 survey respondents (India = 264, United States = 326)	April to May 2020	Not reported	Total food waste: Increase *** amongst respondents with a higher need for cognitive closure (i.e., the desire for definitive answers without ambiguity)
[45]	United States	946 survey respondents	October 2020	Not reported	Total food waste: Decrease: 51% of respondents *** No change: 23% of respondents Increase: 27% of respondents
[46]	China	2126 survey respondents	April to May 2020	Not reported	Total food waste: Decrease: 40% of respondents No change: Not reported Increase: Not reported
[47]	Bogotá, Medellín, Cali, and Barranquilla; Columbia	579 survey respondents	July 2020	Not reported	Total food waste: Decrease: 55% of respondents No change: 31% of respondents Increase: 14% of respondents
[48]	Pakistan (rural)	963 survey respondents	March 2021	Not reported	Total food waste: Decrease: 77% of respondents No change: 19% of respondents Increase: 4% of respondents
[49]	Italy	1078 survey respondents	April to May 2020	Not reported	Avoidable food waste: −37% Bread: −60% Pasta and rice: −44% Meat, fish, and eggs: −50% Milk and dairy products: −51% Vegetables: −49% Fruit: −50%
[50]	Italy	1865 survey respondents	May 2020	Not reported	Total food waste: Decrease: 54% of respondents No change: 43% of respondents Increase: 3% of respondents
[51]	Italy	1500 survey respondents	May 2020	Not reported	Total food waste: Decrease: 52% of respondents No change: 40% of respondents Increase: 8% of respondents
[52]	Bosnia and Herzegovina	3133 survey respondents	October to November 2020	Not reported	Total food waste: Decrease: 0% of respondents No change: 97% of respondents Increase: 3% of respondents
[53]	Russia	1297 survey respondents	October to November 2020	Not reported	Total food waste: Decrease: 15% of respondents No change: 75% of respondents Increase: Not reported
[54]	Portugal	841 survey respondents	May to June 2020	Not reported	Total food waste: Decrease: 36% of respondents No change: 60% of respondents Increase: Not reported
[55]	New Zealand	3028 survey respondents	April to May 2020	Not reported	Total food waste: Decrease: 45% of respondents No change: 55% of respondents Increase: 6% of respondents
[56]	New York, United States	300 survey respondents	August 2020	Not reported	Total food waste: Decrease: 37% of respondents No change: 38% of respondents Increase: 20% of respondents
[57]	Qatar	579 survey respondents	May to June 2020	Not reported	Total food waste: Decrease: 45% of respondents No change: 42% of respondents Increase: Not reported
[58]	Italy	1188 survey respondents	April 2020	Not reported	Total food waste: Decrease: 49% of respondents No change: 45% of respondents Increase: 6% of respondents
[59]	Turkey	511 survey respondents (careless planners and cooks = 90, resourceful planners and cooks = 285, careless planners and resourceful cooks = 136)	January 2021	Not reported	Total food waste: Decrease: 32% of careless planners and cooks, 31% of resourceful planners and cooks, and 29% of careless planners and resourceful cooks No change: 33% of careless planners and cooks, 26% of resourceful planners and cooks, and 24% of careless planners and resourceful cooks Increase: 13% of careless planners and cooks, 4% of resourceful planners and cooks, and 3% of careless planners and resourceful cooks No wasted food: 21% of careless planners and cooks, 39% of resourceful planners and cooks, and 43% of careless planners and resourceful cooks
[60]	United States and Italy	954 survey respondents (United States = 478, Italy = 476)	April 2020	Not reported	Total food waste: Decrease: 49% of respondents No change/increase: 51% of respondents
[61]	United Kingdom	205 survey respondents	June to July 2020	Not reported	Total food waste: Increased
[62]	Bangkok, Thailand	239 survey respondents	June 2020	Not reported	Total food waste: Decrease: 5% of respondents No change: 19% of respondents Increase: 76% of respondents

** p < 0.01, *** p < 0.001.

Table 4. Survey-based, recall studies measuring the perceived quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of Data Collection	Perceived Quantity and Composition of Food Waste	Perceived Changes in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[26]	United Kingdom	473 survey respondents	March 2020	Avoidable food waste: respondents wasted 9% of purchased waste (i.e., purchased and thrown away uneaten) and 7% of cooked waste (e.g., cooked before being thrown away). The most wasted types of purchased waste were green leafy vegetables, carrots, potatoes, and sliced bread. The least wasted types of purchased waste were beef and chicken. The most wasted types of cooked waste were polenta, green leafy vegetables, and white rice. The least wasted types of cooked waste were beef, chicken, and bread.	Not reported
[27]	Mexico	525 survey respondents	December 2020 to January 2021	Total food waste: Fruit: 19% wasted Vegetables: 21% wasted Beef, chicken, and pork products: 10% wasted Fish and shellfish: 4% wasted Milk, yogurt, and dairy products: 10% wasted Eggs and cheese: 6% wasted Tortilla, rice, cereals, and pasta: 15% wasted Bread and pizza: 7% wasted Seasonings: 4% wasted Desserts: 5% wasted	Total food waste: −2% **
[28]	Montenegro	514 survey respondents	May to June 2020	Avoidable food waste: the most wasted types of food were bread and bakery products, followed by fruit and vegetables. Almost none: 17% of respondents Very little: 38% of respondents Reasonable amount: 27% of respondents More than I should: 11% of respondents Much more: 7% of respondents	Avoidable food waste: Decrease: 5% of respondents No change: 74% of respondents Increase: 21% of respondents
[29]	Serbia	1212 survey respondents	May to June 2020	Avoidable food waste (kilograms/week): No wasted food: 46% of respondents <0.25: 22% of respondents 0.25 to 0.5: 21% of respondents 0.5 to 1: 7% of respondents 1 to 2: 2% of respondents >2: 1% of respondents	Avoidable food waste: Decrease: 8% of respondents No change: 63% of respondents Increase: 30% of respondents
[30]	North Macedonia	754 survey respondents	May to June 2020	Avoidable food waste (kilograms/week): No wasted food: 52% of respondents <0.25: 23% of respondents 0.25 to 0.5: 18% of respondents 0.5 to 1: 5% of respondents 1 to 2: 1% of respondents >2: 1% of respondents	Avoidable food waste: Decrease: 5% of respondents No change: 57% of respondents Increase: 38% of respondents
[31]	Canada	8272 survey respondents	August 2020	Avoidable food waste (kilograms/week): 0: 17% of respondents *** <2: 73% of respondents 2 to 4: 20% of respondents 4 to 6: 6% of respondents 6 to 8: 1% of respondents >8: 1% of respondents	Avoidable food waste (kilograms/week): <2: 80% of respondents 2 to 4: 15% of respondents 4 to 6: 5% of respondents 6 to 8: 1% of respondents >8: 1% of respondents
[34]	Spain	6293 survey respondents	May to June 2020	Avoidable food waste: 0.09 kg per capita per week	Avoidable food waste: Decrease or no change: 96% of respondents Increase: 3% of respondents Not applicable: 2% of respondents
[36]	Gweru City, Zimbabwe	169 survey respondents	2021	Organic waste: 35.2 kg per household per week	Not reported
[38]	Turkey	1098 survey respondents	March to June 2020	Avoidable food waste: the most wasted types of food were bakery products, leftover foods, and fruit and vegetables. The least wasted types of food were milk and dairy products, beverages, cooking oil and related products, and legumes.	Avoidable food waste: Fresh fruit and vegetables: decrease *** White meat and products: decrease *** Milk and milk products: decrease *** Packaged take-home foods: decrease *** Bread and flour products: decrease *** Legumes: decrease *** Leftover foods: decrease ***
[39]	Tunisia	284 survey respondents	March to April 2020	Avoidable food waste: the most wasted types of avoidable food were bakery products, vegetables, and fruit. The least wasted types of avoidable food were fish and seafood, meat and meat products, and pulses and oilseeds.	Not reported
[40]	Portugal, Italy, Germany, Brazil, Estonia, United States, Australia, Canada, Singapore, United Kingdom, Denmark, Spain, Poland, Finland, Bangladesh, Argentina, Chile, Ireland, New Zealand, Japan, Malaysia, Indonesia, and Vietnam	204 survey respondents	August to November 2020	Total food waste: the most wasted types of food were fruit and vegetables, meat, dairy products, bread, and fish and seafood. The least wasted types of food were ready-made meals, canned food, milk, cereal and grain products, and potatoes.	Total food waste: Decrease: 15% of respondents No change: 37% of respondents Increase: 45% of respondents Do not know: 3% of respondents
[41]	Peru	418 survey respondents	May 2020	Avoidable food waste: vegetables, fruit, and roots and tubers were the most wasted types of food. No wasted food: 63% of respondents Some wasted food: 35% of respondents	Not reported
[42]	Poland	500 survey respondents	March to April 2021	Total food waste: The most wasted types of food were fruit, vegetables, bread, and dairy products	Not reported
[43]	Greece	2205 survey respondents	April 2020	Total food waste: The most wasted types of food were dairy products, fruit and vegetables, and cold meat. No wasted food: 22% of respondents	Not reported
[44]	India and United States	590 survey respondents (India = 264, United States = 326)	April to May 2020	Not reported	Total food waste: Increase *** amongst respondents with a higher need for cognitive closure (i.e., the desire for definitive answers without ambiguity)
[45]	United States	946 survey respondents	October 2020	Not reported	Total food waste: Decrease: 51% of respondents *** No change: 23% of respondents Increase: 27% of respondents
[46]	China	2126 survey respondents	April to May 2020	Not reported	Total food waste: Decrease: 40% of respondents No change: Not reported Increase: Not reported
[47]	Bogotá, Medellín, Cali, and Barranquilla; Columbia	579 survey respondents	July 2020	Not reported	Total food waste: Decrease: 55% of respondents No change: 31% of respondents Increase: 14% of respondents
[48]	Pakistan (rural)	963 survey respondents	March 2021	Not reported	Total food waste: Decrease: 77% of respondents No change: 19% of respondents Increase: 4% of respondents
[49]	Italy	1078 survey respondents	April to May 2020	Not reported	Avoidable food waste: −37% Bread: −60% Pasta and rice: −44% Meat, fish, and eggs: −50% Milk and dairy products: −51% Vegetables: −49% Fruit: −50%
[50]	Italy	1865 survey respondents	May 2020	Not reported	Total food waste: Decrease: 54% of respondents No change: 43% of respondents Increase: 3% of respondents
[51]	Italy	1500 survey respondents	May 2020	Not reported	Total food waste: Decrease: 52% of respondents No change: 40% of respondents Increase: 8% of respondents
[52]	Bosnia and Herzegovina	3133 survey respondents	October to November 2020	Not reported	Total food waste: Decrease: 0% of respondents No change: 97% of respondents Increase: 3% of respondents
[53]	Russia	1297 survey respondents	October to November 2020	Not reported	Total food waste: Decrease: 15% of respondents No change: 75% of respondents Increase: Not reported
[54]	Portugal	841 survey respondents	May to June 2020	Not reported	Total food waste: Decrease: 36% of respondents No change: 60% of respondents Increase: Not reported
[55]	New Zealand	3028 survey respondents	April to May 2020	Not reported	Total food waste: Decrease: 45% of respondents No change: 55% of respondents Increase: 6% of respondents
[56]	New York, United States	300 survey respondents	August 2020	Not reported	Total food waste: Decrease: 37% of respondents No change: 38% of respondents Increase: 20% of respondents
[57]	Qatar	579 survey respondents	May to June 2020	Not reported	Total food waste: Decrease: 45% of respondents No change: 42% of respondents Increase: Not reported
[58]	Italy	1188 survey respondents	April 2020	Not reported	Total food waste: Decrease: 49% of respondents No change: 45% of respondents Increase: 6% of respondents
[59]	Turkey	511 survey respondents (careless planners and cooks = 90, resourceful planners and cooks = 285, careless planners and resourceful cooks = 136)	January 2021	Not reported	Total food waste: Decrease: 32% of careless planners and cooks, 31% of resourceful planners and cooks, and 29% of careless planners and resourceful cooks No change: 33% of careless planners and cooks, 26% of resourceful planners and cooks, and 24% of careless planners and resourceful cooks Increase: 13% of careless planners and cooks, 4% of resourceful planners and cooks, and 3% of careless planners and resourceful cooks No wasted food: 21% of careless planners and cooks, 39% of resourceful planners and cooks, and 43% of careless planners and resourceful cooks
[60]	United States and Italy	954 survey respondents (United States = 478, Italy = 476)	April 2020	Not reported	Total food waste: Decrease: 49% of respondents No change/increase: 51% of respondents
[61]	United Kingdom	205 survey respondents	June to July 2020	Not reported	Total food waste: Increased
[62]	Bangkok, Thailand	239 survey respondents	June 2020	Not reported	Total food waste: Decrease: 5% of respondents No change: 19% of respondents Increase: 76% of respondents

** p < 0.01, *** p < 0.001.

While several survey-based, recall studies reported on perceived changes in food waste generation during the pandemic, it is unknown if most of these changes were significant, as statistical significance was rarely reported. A cross-national study in India and the United States concluded that both Indian and American respondents with a higher need for cognitive closure (i.e., the desire for definitive answers without ambiguity) perceived themselves to own less food during the pandemic, which led to an increase in their food purchasing, thereby leading to a self-reported increase in household food waste generation (p < 0.001) [44]. In another American study, perceived food waste generation was found to have decreased (p < 0.001) [45]. Similarly, self-reported food wasting decreased by about 2% (p < 0.01) in Mexico [27]. In Turkey, Çavuş et al. [38] observed self-reported decreases in the generation of seven avoidable food waste categories, including fruit and vegetables (p < 0.001), white meat and products (p < 0.001), milk and milk products (p < 0.001), packaged take-home foods (p < 0.001), bread and flour products (p < 0.001), legumes (p < 0.001), and leftover foods (p < 0.001). No other statistically significant changes in food wasting were reported in any of the other survey-based studies included in this review.

Perceived household food waste generation during the COVID-19 pandemic was reported to have decreased in six survey-based, recall studies; however, none of these studies used comparison tests to determine if the reported differences were statistically significant. Forty percent of respondents in Chen et al.’s [46] Chinese study self-reported a decrease in total food waste generation; however, the percentage of respondents who perceived no change or an increase in their food waste generation was not reported. Self-reported decreases were also observed in Columbia [47], rural Pakistan [48], and Italy [49,50,51]. Most respondents in Columbia (55%) [47] and Pakistan (77%) [48] claimed to have wasted less food during COVID-19 compared to before the pandemic. In Italy, Principato et al. [49] reported that avoidable food waste decreased by 37% in their participant sample, while Scacchi et al. [50] and Vittuari et al. [51] reported that 54% and 52% of respondents self-reported a decrease in total food waste generation, respectively.

Perceived household food waste generation was reported to have remained unchanged during COVID-19 in seven survey-based, recall studies, although these findings were not supported by any statistical tests for differences. In Serbia and North Macedonia, most respondents (63% and 57%, respectively) reported that their avoidable food waste generation remained unchanged during pandemic circumstances [29,30]. Further, 97% of respondents in Bosnia and Herzegovina [52], 75% of respondents in Russia [53], 74% of respondents in Montenegro [28], 60% of respondents in Portugal [54], and 55% of respondents in New Zealand [55] reported wasting the same amount of food before and during COVID-19.

Six survey-based, recall studies observed that a similar number of participants self-reported either a decrease in household food wasting or no change to their food waste generation during the pandemic. An American study found that 37% of respondents claimed to have thrown away less food during COVID-19, while 38% perceived no change to their total food waste generation [56]. In Qatar, 45% of respondents self-reported a decrease in total food waste generation, while 42% reported no change [57]. Forty-nine percent of respondents in Pappalardo et al.’s [58] Italian study perceived to discard less food waste during COVID-19, while 45% claimed that their food wasting had not changed. Respondents labelled as “careless planners and cooks” in Yekin Özbük et al.’s [59] Turkish study self-reported a decrease (32%) or no change (33%) in total food waste generation during COVID-19. Similarly, 29% of “careless planners and resourceful cooks” claimed to have decreased their food waste generation, while 26% reported no change [59]. Vidal-Mones et al. [34] dichotomized responses and reported that 96% of respondents in Spain self-reported either a decrease or no change in their avoidable food waste generation during COVID-19. Why response options were grouped and reported together is unclear. Similarly, a cross-national survey in Italy and the United States found that 49% of respondents self-reported perceived decreases in household food wasting during COVID-19, while the remaining 51% reported no changes [60]. However, responses to Rodgers et al.’s [60] survey were dichotomized in a manner that favored the hypothesized study outcome. It should be noted that none of these findings were supported by any comparison tests for statistically significant differences.

Lastly, self-reported household food waste generation was found to have increased during the pandemic in three survey-based, recall studies; however, these results were also not supported by any statistical tests for differences. Filimonau et al. [61] suggested that total household food waste generation increased during COVID-19 in the United Kingdom. Forty-five percent of respondents in an international study that surveyed participants in 23 countries self-reported an increase in total food waste generation during the pandemic [35]. Additionally, in Bangkok, Thailand, 76% of respondents perceived they were wasting more food during COVID-19 [62].

Despite the number of studies that have used self-reported recall data to investigate household food wasting under pandemic circumstances, methodological differences and limitations have led to varied results. Neither of the research questions explored in this study—(1) what is the quantity and composition of household food waste during the COVID-19 pandemic; and (2) has there been a change in the quantity and/or composition of household food waste since the onset of the pandemic?—can be adequately answered by reviewing these 35 studies of self-reported recall data, despite these studies accounting for 85% of the articles currently published on this topic. Methodological differences between studies of self-reported recall data, such as the use of various food waste measurement units, scales, and categories, have resulted in incomparable findings. Without the ability to analyze results across time and geographies, the state of household food wasting during the COVID-19 pandemic is still relatively unknown. While there does not appear to be a clear trend in food wasting during the pandemic according to these self-reported results, it is not possible to accurately determine if changes to the quantity and/or composition of household food waste have occurred during COVID-19. The accuracy and reliability of the findings observed in these 35 articles of self-reported recall data are also limited by methodological limitations, such as the probable presence of social desirability bias, recall bias, and self-selection bias. Moreover, statistical significance was rarely reported in these studies. Only 15% (n = 4) of self-reported recall studies that reported on perceived changes in food waste generation during the pandemic used statistical tests for differences to support results. The value of the 22 articles that reported changes to household food wasting during COVID-19 that were not supported by any comparison tests for statistically significant differences is minimal.

Only one study included an interview component (

Table 5. Interview studies measuring the perceived quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of Data Collection	Perceived Quantity and Composition of Food Waste	Perceived Changes in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[61]	United Kingdom	16 interviewees	June 2020	Not reported	Total food waste: some interviewees self-reported a decrease, while others self-reported an increase

). In June 2020, Filimonau et al. [61] used semi-structured interviews, in addition to a survey, to explore themes related to food consumption and behavior before, during, and after COVID-19 lockdowns in the United Kingdom. Some participants self-reported a decrease in household food waste during lockdown periods due to decreases in food shopping frequency, heightened financial concerns, and/or perceived increases in time available for food preparation [61]. Other participants self-reported the opposite—an increase in household food wasting during lockdown periods—due to increases in the amount of food purchased per grocery shopping trip and/or the frequent preparation of more food than needed [61].

3.3. Studies Using Secondary Data

Two of the articles included in this review used secondary data to estimate household food waste generation (

Table 6. Secondary data studies measuring the quantity and composition of household food waste during the COVID-19 pandemic.

Study	Geography	Sample Size	Time of Data Collection	Perceived Quantity and Composition of Food Waste	Perceived Changes in Food Waste Quantity and Composition during COVID-19 Compared to before the Outbreak
[63]	Spain	Not reported	March and April 2020	Not reported	Total food waste: +12%
[64]	United States	3298 observations	Not applicable	32% of total food purchased was wasted	Not reported

). Studies using secondary data are typically used to assess waste generation at the national level, rather than the household level. Aldaco et al. [63] used secondary data obtained by the Spanish Ministry of Agriculture, Fisheries, and Food to examine the potential implications of COVID-19 on household food wasting. Through an analysis of the inputs and outputs of the Spanish food supply chain, Aldaco et al. [63] concluded that households may have wasted 12% more food during COVID-19 compared to before the outbreak. Economically, it was estimated that during the emergency lockdown period, the value of the food thrown away by each Spanish citizen was €4.7 EUR per week, which is €0.9 EUR more per week than the pre-COVID estimates [63]. Scharadin et al. [64] applied data from a pre-pandemic household food waste study (see Yu and Jaenicke [65]) to the pandemic situation to estimate household food waste generation during COVID-19 in the United States. Based on the extrapolated calculations, Scharadin et al. [64] concluded that households may have thrown away 32% of the total amount of food they purchased during the pandemic. However, these results should be interpreted with caution as food waste quantities were not directly measured by the researchers, and statistical significance was not reported in either study.

4. Conclusions

The 41 studies included in this review provided a preliminary understanding of household food wasting within the first two years of the COVID-19 pandemic. The average total amount of household food waste generated during COVID-19 was 0.91 kg (SD = 0.19 kg) per capita per week. On average, the total amount of avoidable food waste generated was 0.40 kg (SD = 0.18 kg) per capita per week, and the average total amount of unavoidable food waste generated was 0.51 kg (SD = 0.09 kg) per capita per week. Fruit and vegetables were typically found to be the most wasted types of total, avoidable, and unavoidable food waste, often followed by bread and bakery products.

While several studies reported on actual or perceived changes in household food waste generation during the pandemic, only five studies reported statistically significant changes. Individuals with a higher need for cognitive closure (i.e., the desire for definitive answers without ambiguity) self-reported an increase in total household food waste generation [44], while perceived total food waste generation was found to have decreased in two other studies [27,45]. No significant changes were reported for total avoidable food waste generation; however, two direct measurement studies reported a significant increase in total unavoidable food waste generation [16,17]. While these results are inconsistent, all the studies (n = 2) that observed significant decreases in household food wasting were studies of self-reported recall data that measured perceived, rather than actual, food waste generation. Only 6% of the studies of self-reported recall data included in this review concluded that household food waste generation significantly decreased during the pandemic, whereas all the direct measurement studies with statistically significant results observed no significant change to the generation of total food waste at the household-level. Thus, the COVID-19 pandemic has probably not had a considerable impact on total household food waste generation. Of particular importance to the achievement of SDG 12.3, it appears that COVID-19 has also not acted as a natural intervention to reduce household food wasting as the generation of avoidable household food waste has remained unchanged. However, the pandemic has probably had a considerable impact on unavoidable household food waste generation. The significant increase in unavoidable food waste observed in both direct measurement studies with statistically significant results indicates a probable reallocation of waste from places that were inaccessible or less frequented during the pandemic (e.g., places of employment) to the household level. A change in the point of waste generation has the potential to increase demand on municipal waste management programs, as commercial waste is often managed independent from municipalities.

Significant changes in the generation of particular types of food waste were also observed. One direct measurement study noted a significant increase in the generation of avoidable ‘other food’ [16], while another observed a significant decrease in a category with a shared name, albeit slightly different definition [17]. Both of these direct measurement studies also observed significant increases in the generation of unavoidable fruit and vegetables and unavoidable ‘other food’ during the pandemic [16,17]. Only one survey-based, recall study noted significant changes to the generation of self-reported food waste categories. Significant decreases were observed in the perceived generation of several types of avoidable food waste, including fruit and vegetables, white meat and products, milk and milk products, packaged take-home foods, bread and flour products, legumes, and leftover foods [38].

Most studies were conducted in Europe (n = 17) or North America (n = 8), while only five studies were conducted in Asia, and even fewer were conducted in South America (n = 3), Africa (n = 3), and Oceania (n = 1). An additional four cross-national studies were conducted, including one that surveyed respondents in 23 countries across five continents. Additional research in Asian, South American, African, and Oceanic nations are needed to investigate possible regional and/or global consistencies in household food wasting during pandemic circumstances.

Further, most of the studies included in this review are limited by their reliance upon indirect measurements of self-reported recall data (n = 35) or secondary data (n = 2). Studies using self-reported recall data are susceptible to independent interpretation, recall bias, and social desirability bias. Thus, perceived household food waste measurements collected through surveys, food diaries, and interviews, are often underestimated [21,22,66,67]. Underestimating waste generation may hinder a municipality’s ability to effectively operate their curbside waste management programs, especially during unprecedented circumstances when waste management operations may experience delays and complications. In addition, underestimation may lead to landfill capacity and planning issues, and impact the achievement of emission reduction targets. Further research is needed to adequately determine the impact of the pandemic on household food waste generation [68,69], as the findings summarized in this review vary substantially and statistically significant results are limited. Scholars looking to contribute to this growing body of literature should use direct measurement methodologies to accurately and reliably determine if there have been changes in the quantity and/or composition of household food waste generation since the onset of the pandemic. While direct measurement studies are expensive to conduct, they are often thought to be the most objective and accurate food waste measurement methodology. Furthermore, the results of this review have demonstrated the utmost importance of thoughtful and intentional study design. While researchers may have experienced a sense of urgency to begin collecting data as soon as the pandemic began, rigorous, scientific methodologies should be prioritized moving forward. In the future, when researchers inevitably experience a similar sense of urgency due to other pandemic or crisis situations, it may be worthwhile to follow an experimental study design that was created under ‘normal’, non-urgent circumstances, rather than develop and conduct a novel study under the tremendous pressures of creating new knowledge in and about a fleeting moment of time.

An adequate and reliable understanding of the quantity and composition of household food waste generation under pandemic circumstances can be used to improve the management of municipal waste during the remainder of the COVID-19 pandemic. An understanding of how and to what extent household food waste generation changes during a pandemic can also be used to develop best practices for municipal waste management programs under crisis circumstances and be leveraged to influence policies and programs that aim to reduce, divert, and sustainably manage household food waste.