Identifying the Drivers of Food Waste in University Canteens in China: A Qualitative Approach

The global food crisis has made food waste reduction an important area for research and practice. In China, food is frequently wasted in university canteens. Identifying the factors involved is critical for reducing waste and preserving resources and the environment. In contrast to previous studies of canteen food waste, which have mainly used quantitative research methods, this study adopted a qualitative approach to reveal the self-reported causes of food waste by students who eat at the canteens of a university in South China. The study identified material, economic, psychological, social, cultural, and health dimensions that influence food waste in university canteens. The results validate some previous findings and add novel factors not previously identified. This study argues that food waste is embedded in a complicated socio-cultural context, and hence it is difficult to take simple and direct management measures to reduce waste. Measures should be implemented to improve both the consumers’ consciousness of frugality and ecological conservation, and the quality and palatability of the served food.


Introduction
Food waste threatens global food security and can exacerbate food crises (Gille, 2012;Grote, 2014;Premanandh, 2011;Xue et al., 2017).According to the United Nations Food and Agriculture Organization (FAO), total annual global food waste is about 1.3 billion tons, which is equivalent to one third of total annual food production and represents a direct economic loss of US$750 billion (FAO, 2011).China generates significant food waste (Cheng et al., 2012;J. Liu et al., 2013).A report by the Chinese Academy of Sciences estimated that the amount of food wasted in the urban catering industry in China is about 17 to 18 million tons per year, which would be enough to feed 30 to 50 million people for a year (Cheng, Jin, et al., 2018).
Food waste has negative impacts on resource availability and the environment (J.Liu et al., 2013;L. E. Wang et al., 2015L. E. Wang et al., , 2021)).FAO (2011) reported that food waste is not only a waste of food itself but also of the water, energy, land, and materials used to produce it, and thus causes unnecessary greenhouse gas emissions.According to Hu et al. (2013), the amount of food wasted in China in a year is equivalent to wasting about 18.4 million hectares of sown area, 458.9 million tons of fertilizer, and 31.61 billion cubic meters of agricultural water.Therefore, reducing food waste not only ensures food security but also helps protect natural resources.
University canteens are one of the major sites of food waste in China (Cheng, Li, et al., 2018;Ma et al., 2021).In 2020, there were 2,738 colleges and universities in China and 32.853 million college students, the highest number of any country (National Bureau of Statistics, 2021).A survey by Zhu et al. (2020) of 30 colleges and universities across China found that university students wasted 67.55 grams of food per meal per capita; consequently, the total amount of food wasted by university students nationwide is estimated at more than 1.3 million tons per year.A large amount of food waste has caused widespread social concern, so that Chinese central government launched an anti-food waste law in 2021.It is necessary to identify the factors that affect food waste among college and university students and propose management measures.
Existing studies have identified three main categories of factors influencing food waste in school canteens: demographics (Ma et al., 2021;Mirosa, Loh, & Spence, 2016;Qian et al., 2021), social and family structure (Y.Liu et al., 2016;N. Wang, 2010;Wu et al., 2019), and dining factors (Mirosa, Munro, et al., 2016;Qian et al., 2019;Richardson et al., 2021;Silvennoinen et al., 2015).However, these studies have mainly used quantitative methods to examine variables pre-determined by their authors that are easily quantifiable.Consumers' subjective perceptions and experiences of food waste in natural consumption situations have been largely ignored.
Food waste is embedded in the complex socio-cultural context of consumption (Evans, 2012;Waitt et al., 2016) .As Painter et al. (2016, p. 496) stated, ''food waste.is shaped by a complex interplay of personal and contextual factors that may be beyond the control of individuals.''Food waste behavior can be influenced by multiple physical, economic, social, cultural, and psychological factors (Roodhuyzen et al., 2017;Thyberg et al., 2016;Zhang et al., 2019).Some factors are difficult to quantify and need to be identified through qualitative research methods.Qualitative methods allow research subjects to express their attitudes, beliefs, and behaviors toward food waste directly and freely, thereby uncovering influences that scholars may not anticipate in advance (Nikolaus et al., 2018).
This study used a qualitative approach to explore the causes of food waste by students in university canteens.We focused on food waste at the consumption end, more specifically plate waste, which refers to food that has been sold to consumers but not consumed and is thus edible and avoidable (Williams et al., 2011).The canteens of a university in Guangdong province, China, were selected as a case study.No theoretical hypotheses were set during the study.The focus aim of this study was to identify as many drivers of plate waste as possible from students' self-reported information.

Literature Review
As mentioned, studies have examined food waste in school canteens from three main perspectives: demographic characteristics, social and family structure, and dining characteristics.Many factors and variables have been identified and tested in each area.

Demographics
The plate waste of student consumers in school canteens has been shown to be correlated with demographic characteristics such as gender, education level, and body mass index (BMI).Numerous studies have found that female adolescents statistically cause more waste than males, possibly because they generally eat smaller meals (Al-Domi et al., 2011;Qian, Li, Liu, & Wang, 2022) and are more likely to waste food when eating from larger plates (Ma et al., 2021;Richardson et al., 2021).Studies have also found that there are differences in the types of food wasted by male and female students, with male students wasting more vegetables and poultry and female students wasting more rice and flour-based staples (Li et al., 2018).In addition, Qian et al. (2021) found that more educated students were less likely to waste food, with undergraduate students being more likely to waste food than graduate students.In another study, Qian, Li, Liu, and Wang (2022) demonstrated that thinner students wasted more food; in other words, students with higher BMIs were less likely to waste food.
Students' values and knowledge can also influence their food waste behavior.Studies have shown that the less students know about the impacts of food waste, the more likely they are to waste it (Qian et al., 2021).In addition, hedonistic values can cause students to be more focused on sensory pleasure and satisfaction, and more inclined to not finish their food if they do not get pleasure from eating (Mirosa, Loh, & Spence, 2016).

Social and Family Structure
China's rapid development in the past four decades has led to an increase in income and a higher material standard of living for most people (Lee, 2017).The transition of Chinese society to a consumer society and the gradual loss of consciousness of the need for frugality has also led to an increase in food waste (N.Wang, 2010).In addition, many schools pay little attention to food waste issues, and urbanization has led to a lack of farming experience among students, reducing their awareness of the preciousness of food (Y.Liu et al., 2016).
Students' food waste behavior has also been related to their family's economic status and structure.The vast majority of students are not financially independent and their living expenses are mainly paid by their families.For example, Ma et al. (2021) found that students from affluent families waste more food.Wu et al. (2019) suggested that less well-off students are more concerned about the price of meals, and better-off students are more concerned about nutrition and dietary preferences, which leads to the latter ordering too much food to finish and then wasting it.In the Chinese social context, Y. Liu et al. (2016) argued that due to China's one-child policy, parents try to satisfy their children's needs and spoil them, which can encourage food waste habits.

Dining Factors
Plate waste is influenced by food, plate shape, meal times, and other dining factors.First, dietary patterns affect food waste.Studies have shown that the buffet model generates a lower food waste volume and waste rate than the set meal model (Y.Liu et al., 2016;Silvennoinen et al., 2015).In China, there are two basic dietary patterns: the southern rice pattern and the northern wheat pattern.Qian, Li, Liu, Wang, McCarthy, and Jin (2022) demonstrated that food waste in the canteens of universities in South China, which mainly follow the rice mode, is higher than that in the canteens in the north, which mainly follow the wheat mode.The rice mode is also known as ''fan-cai'' ( -) mode, in which people usu- ally order one rice and many dishes (Chang, 1977), while in wheat mode proper amount of dishes is usually served with noodles in one bowl.Thus, it is more likely for people to over-order food in the rice mode.For many students, not having enough time to finish their food is a significant cause of waste.Indeed, studies have shown that more food is wasted when students are limited to 20 minutes of meal time than when they have five more minutes to eat (X.Zhao & Manning, 2019).
Food quality has been shown to significantly affect wasteful behavior (C.Zhao et al., 2019;X. Zhao & Manning, 2019).The tastier the food, the less waste it will cause (Mirosa, Munro, et al., 2016).Wu et al. (2019) revealed that dishes served in schools are often wasted because students think they are not tasty.Beausang et al. (2017) found that visually unappealing food is wasted more, possibly because such food is more likely to be unappetizing.Lorenz et al. (2017) argued that individuals' sense of control over leftovers is much lower in the presence of larger portions of food.Therefore, the larger the portion and plate size, the more food is wasted (Xu et al., 2020;X. Zhao & Manning, 2019).Mirosa, Munro, et al. (2016) found that the greater the variety on a menu, the more difficult it was for students to make choices; they tended to regret their choices and not finish the food they chose.Richardson et al. (2021) found that oval plates caused less waste than round plates, because diners perceived oval plates as not holding as much food as round plates.
Studies have mainly used quantitative methods to examine the causal mechanisms of various factors affecting food waste in school canteens.However, the sociocultural context in which food waste occurs has not been adequately considered.For instance, many studies have pointed out that China's face (mianzi) culture can induce over-ordering of food and wastage in the context of restaurant consumption (Filimonau et al., 2020;Long et al., 2022).However, it is still unclear how culture influences food waste in university canteens.Most universities in China are public, and this education system is set up to provide universal access to higher education.The principle of inclusiveness also applies to food services in university canteens (Yang, 2021).There is little research into how this particular system affects food waste.Food waste in canteens should not be understood in isolation from students' social life in university.The advantage of the qualitative approach is that it can contextualize students' dining and food waste behaviors to reveal the complex causes of food waste.Therefore, this study chose to use qualitative methods to examine factors impacting university students' attitudes and behaviors of food waste in canteens.

Case Selection
We chose a university in Guangzhou for our case study.This university is a participant in China's ''211 project,'' which is a project to build approximately 100 higher education institutions to meet the challenges of the new technological revolution of the 21st century and to ensure they reach the level of world-class universities.Among more than 100 universities participating in the same project, the case study university is ranked in the mid-to upper level according to its teaching and research capabilities.This university can be considered a typical example of the university group.The analysis of this example can give a good picture of the general situation of university canteens in China.The selected university has four campuses, of which we chose the one located in Guangzhou Higher Education Mega Center, because of its ease of access for us and our familiarity with its canteens.
There are three canteens (Nanyuan, Hanyuan, and Xiangyuan) on the studied campus, which provide catering services for more than 12,000 students from 11 colleges.Xiangyuan is a simple dining hall located on the first floor of the teaching building; it mainly serves set meals and can accommodate fewer than 300 students.Nanyuan and Hanyuan have three floors for service and are designed to accommodate a total of 18,000 people.The first and fourth floors of Nanyuan provide specialties with higher prices, mostly in the form of set meals, such as rice with teppanyaki or Cantonese barbecue, clay-pot rice, rice noodles, wheat noodles, and dumplings.The second floor mainly serves affordable food at a moderate price, and it can accommodate the largest number of students.The food is served in the form of ''fan-cai'' (Chang, 1977), in which students usually order rice and some side dishes.The first and second floors of Hanyuan are like the second floor of Nanyuan in that they offer ''fan-cai'' cuisine.The third floor of Hanyuan provides halal cuisine.Students eat most often at Nanyuan and Hanyuan, so this study focused on dining and waste at these two canteens.

Data Collection
Data were collected from October to December 2021 using the semi-structured interview method.The interview questions of students were designed according to our research questions and divided into two parts.The first part elicited basic demographic information about the interviewees, including gender, year of enrollment, major, and hometown.The second part contains questions about the respondents' eating behaviors, such as frequency of eating in the canteens, canteen choices, food choices and preferences, food waste and reasons, and awareness of food waste.Please see the supplementary material for the detailed interview questions.
We used purposive and convenience sampling to select respondents.In purposive sampling, it is important to find key informants who are knowledgeable about the study subject.We interviewed a canteen manager to learn about food preparation and service in the canteens, and how the management responds to food waste (the interview questions are included in the Supplemental Material).Students were selected on a convenience basis.Those students who were available and agreed to be interviewed were selected as the sample.We intended to cover students from different grades and majors.Interviews with students stopped when the information was saturated (Bowen, 2008).
In the end, the interviews were conducted with 60 undergraduate students and one canteen manager.The interviewees included 17 male and 43 female students from 10 colleges, and they represented all 4 undergraduate years and 10 provinces in China (Table 1).The average duration of the interviews was 28 minutes, with the longest being 85 minutes and the shortest being 10 minutes.The interviews were recorded with the consent of the interviewees.All interviewees were anonymized and the interviewed students were labeled as S01 to S60.

Data Analysis
Data were analyzed using the thematic analysis method (Braun & Clarke, 2006).First, we transcribed the interview recordings and repeatedly read the transcripts to familiarize ourselves with them.Second, three members of the research team conducted a preliminary analysis of the transcripts to generate the initial codes.Fifty-four initial codes related to the causes of food waste were identified.Third, the research team members conferred to filter, merge, and integrate the initial codes.Fifteen secondary codes were obtained, which were food taste, food appearance, food quantity, foreign objects, regional differences in food culture, local food culture, the notion of a balanced diet, no overeating, mealtime competition, gender impression management, pressure from co-diners, cheap food prices, economic affluence, psychological eating habits, and frugality.The fourth step was to categorize these 15 codes into themes; finally, we obtained 6 themes (Figure 1).The fifth step was to return to the interview transcripts to contextualize the themes and sub-themes and write up the research findings.

Material Factors
Foreign Objects.The students wasted meals containing foreign objects due to improper handling of ingredients or poor cleaning practices.A number of interviewees mentioned finding foreign objects such as small stones, steel wire, plastic bags, and bugs in their food.After finding foreign objects, many chose to waste part or all of the dish.One student (S50-female) said, ''I ordered a green vegetable once before.Then as I was eating it, I saw some dead worms inside.I just didn't want to eat that meal at all.''Some of the students complained about eating steel wire, so the canteen manager asked the kitchen not to use steel wool: ''Steel wool balls have now been prohibited.But some employees still secretly use it.It is more efficient to use steel wool to clean'' (the manager-male).
Because the canteens must serve a large number of dishes to thousands of students every day, it is difficult for them to handle ingredients carefully.In particular, the handling of some ingredients is complicated, such as potato peeling, fish scaling, and poultry plucking, which makes cleaning work more difficult.Thus, improper handling of ingredients happens from time to time.For example, some of the students wasted fish because the scales were not removed, ''I won't eat the fish skin because the scales are not removed'' (S44-female).According to the manager, this cause of food waste is difficult to avoid.Food Taste.People often waste food that tastes bad (Roodhuyzen et al., 2017).Again, because of the high volume of meals served, canteens have difficulty ensuring that the meals taste good, and many dishes thus taste bad or are undercooked.For example, some of the students wasted fish because it tasted too fishy: ''It is not that I do not like fish, but some fish are so fishy that I really cannot eat them after one or two bites'' (S50-female).Other students wasted food because it did not taste right: ''I felt that the wontons were cooked with no flavor and lost their original characteristics.They were cooked in plain water with a little bit of condiments and chili pepper.It was awful'' (S42-female).Some of the students wasted their meals because they were raw: ''Like this frozen chicken stir-fry with sauerkraut, the chicken is not fully cooked, it is like a gel and not fully heated'' (S53-male).The interviewees said they would not eat half-cooked meals.
Food Appearance.Many dishes could not be identified by their appearance.The canteens do not set up a name menu for each dish, which leads many students to order them by mistake.''Sometimes I get confused when ordering.For example, once the canteens served scrambled egg with green vegetable stalks, but I saw it as scrambled egg with bitter melon.After ordering I realized it was green vegetable stalks, but I wanted to eat bitter melon.So, I ate the egg and left the green vegetable stalks'' (S55-male).Even when their order was correct, some of the students disliked the appearance of certain dishes and wasted them: ''I like to eat stir-fried beans with eggplant.I usually eat the eggplants that look plump and have some leftover that are wrinkled'' (S48-female).Many studies have found that ugly and suboptimal food is more likely to be wasted (Beausang et al., 2017;Hartmann et al., 2021); this also occurred in the university canteens analyzed here.
Food Quantity.Food waste happens when too much food is provided.In most university canteens in China, staff members serve food to students rather than students serving their own food.The biggest problem caused by this system is that canteen staff do not care about the situational demand of the students.For example, S09 (male) had leftovers every time, and his reason was that he ''usually cannot finish it, feeling that one liang ( , equal to 50 grams) of rice is too little, and two liang is too much.''Some students require more than one portion and but less than two.
Research has found that female students waste more food than males (Qian et al., 2019).In our interviews, the majority of those who mentioned that there was ''too much'' food were female students.For instance, ''that set meal gives too much rice, it's too filling, so there will be leftovers'' (S56-female); ''when I order beef noodles at Hanyuan, I cannot finish it because the portion is too large'' (S49-female).Our interviews also showed that the female students generally ate less than their male counterparts and were more likely to engage in wasteful behavior when offered the same amount of food.

Economic Factors
Cheap Food Prices.Our study found that the low price of canteen meals also contributed to food waste.A canteen at a public university will try to keep its dishes at an affordable price for most students.The interviewed manager said that the regulations of the food service center of the university specified a 2:5:3 ratio of meal prices in the canteens: 20% of the dishes cost from 5 to 8 yuan, 50% from 3 yuan to 5 yuan, and 30% from 1 yuan to 3 yuan.The prices thus cannot be changed at will, and the cheaper dishes account for more of the menu.
When they had to waste food, the students often chose to waste cheaper meals, as they felt less of a psychological burden than when wasting expensive meals.''I think this food is cheap, so it should not matter if I cannot eat it all'' (S33-female).Ultimately, this could lead to the notion that expensive meals should be eaten and cheap meals can be wasted.For example, S05 (female) stated, ''I will eat expensive meals first, the cheap meals I can leave without eating.''As a result, cheaper food is wasted more often.This point helps explain why a large amount of green vegetables are wasted in school canteens.
Economic Affluence.Variety-seeking is part of human nature and it affects how people eat (Fischler, 1988;Quan et al., 2004) .Students want to eat as many kinds of food as possible to satisfy their quest for variety.For some students, financial conditions limit them from ordering too much food, while those who are well-off have no such restrictions.For example, interviewee S60 (female), who comes from an affluent family, explained that she ordered a lot of dishes: ''I just want to eat these dishes, that's all.When I order, it is a little bit more than my meal size.''She will order whatever she fancies without considering the waste problem.This echoes the findings of previous studies (Wu et al., 2019).
Over the past four decades, China has undergone reform and opening-up and vigorously developed its economy, and income levels and living conditions have generally improved (Lee, 2017).Society has also replaced a frugal lifestyle with consumerism, and people are no longer content with basic necessities; such hedonism means that people have less self-restraint and are susceptible to temptations (N.Wang, 2010).This consumerism is reflected in student canteen dining and is partly responsible for food waste.

Psychological Factors
Psychological Eating Habits.In everyday life, people develop different eating habits, and certain eating habits manifest as psychological traits.For example, some people do not eat certain foods not because of their negative physiological effects, but because they categorize the foods as inedible and untasteful.Such eating habits can also result in food waste.For some students, the ingredients in a dish have different levels of edibility.For example, student S53 (male) stated, ''I usually have some side dishes left over, such as the vegetable in the pork dish with salted vegetables, the fungus in the steamed chicken dish with tree fungus, the broccoli in the fried beef with Chinese broccoli.''All of these leftovers are edible, but S53 just wasted them habitually.
Frugality.Students' lack of frugality can lead to food waste.Some of the interviewees believed that they should prioritize their own dining experience and that forcing themselves to finish their food would be unpleasant: ''I would be happier if I wasted it; forcing myself to eat it might be unbearable and unnecessary'' (S48-female).Some of the interviewees also felt that they did not need to be ashamed of not finishing their meal: ''I think everyone has something they don't eat, I think it's normal'' (S33-female).In the absence of psychological restraint, food waste occurs.Some even did not recognize the concept of food waste: ''I don't really strongly feel that leftovers are waste'' (S45-female).
Better education can enhance students' frugality and thus reduce their wasteful behavior.Many of the interviewees said that they were strongly influenced by their family environment.''Since I was a kid, my parents have told me not to waste food.They would also set an example.I think this kind of teaching is influential'' (S54-female).Students can develop and internalize a strong sense of frugality from their family members.Students who are conscious of the need to save will engage in less food waste behavior.

Social Factors
Mealtime Competition.The meal times in China's university canteens are relatively fixed, embedded precisely between classes and break activities.For example, the studied canteens serve lunch from 10:40 to 13:00 and supper from 16:20 to 19:00.The consequence of the relatively concentrated meal times is crowding and competition.The number of students eating during peak hours and the long queues for meals make it impossible for students to select their favorite dishes.With a limited supply of favorite dishes and the necessity of eating, students can only choose dishes they do not prefer or even dislike, or are forced to try unfamiliar dishes, resulting in a higher chance of food waste.For example: Q: Can you usually get your favorite food to eat? A: Generally, I can.If I go late the choice is reduced, and most of the options are unappetizing.If I come late, first of all there is not much food, and I lose out on the best dishes.Sometimes you will go back and forth a few times, you still do not see what you want, and you are forced to order something that is at least acceptable.And then after ordering it, it won't be finished, and more food will be left behind than usual.(S48 -female) University students are now under great pressure, with classes, club activities, competitions, and other learning activities filling their college life.It is not uncommon for learning activities to squeeze students' meal times.C. Zhao et al. (2019) found that when students are restricted to a short meal time, they become more wasteful.Food waste occurs when learning or club activities delay or shorten students' meal times.As interviewee S40 (female) said, ''You need to rush to the line, rush to eat, and then rush to class.Many times, I can't finish eating quickly and there will be a lot left over.'' The university has noticed that some students are late for meals and set up a delayed service window in each canteen.However, students do not rate the meals at this window very highly.''The reserved dishes are left for so long that they will definitely taste a little bit worse,'' said the canteen manager.
Gender Impression Management.Some students, especially female students, also waste food because they have to manage their role or image in the eyes of others.For example, interviewee S36 (female) said, When we all eat together, for example, one girl is very thin and eats very little and has a lot left over.Another girl is fatter and finishes all her food.Then who do you think will feel-not ashamed, but uncomfortable?I think it might be the fatter girl.She may think: ''no, I can't eat so much next time.I should eat less and lose weight.''I think this situation might happen.She might compare herself with others.She won't feel, ''I am proud that I have eaten all of my food,'' but ''I eat so much,'' and then feel ashamed.
Although it is only an example, this notion reflects social psychology.Some female students not only have to maintain their gender roles in the eyes of the opposite sex, but also manage the impression they have in the eyes of other women.This impression is often a stereotype: the idea that women eat less.It thus becomes a matter of ''shame'' to finish a meal.Wasting food becomes a negative consequence of managing gender perceptions.
Pressure From Co-Diners.In addition to gender impressions, co-diners can cause stress.When people dine together, when one person finishes eating, some people will stop eating and leave with their companion.''There are times when there will be leftovers because of my boyfriend, because I just can't make him wait.So, I just stop eating and leave with him'' (S48-female).Different individuals eat different amounts of food at different speeds.When a co-diner is left waiting, this can induce the other party to end the meal early and waste food.

Cultural Factors
Regional Food Culture Differences.China is a country with rich food cultures that vary from region to region (Lin et al., 2020).A large number of students enrolled at the studied university come from outside Guangdong province, and they have food habits that differ from the local culture.Such regional cultural differences could induce food waste.
Most of the canteen dishes at this university reflect the local Cantonese food culture, and tend to be sweet and light in taste.Local flavors can satisfy the majority of Guangdong students.However, students from elsewhere must adapt to the local cuisine, and may waste food during this adaptation process.An interviewee from Jiangxi province, where people like eating spicy food, commented: ''One of the greens I am served most often is Chinese flowering cabbage.It has a typical Cantonese flavor, fried with no salt taste at all'' (S39-male).Because the greens did not taste salty and spicy enough, he did not finish them every time.Another student (S26-male) from Anhui province mentioned, ''I cannot accept the way of making chicken soup in Guangdong.I am fine with the soup but do not like the chicken meat, which has no flavor at all.I do not eat the meat at all when I order it.'' The canteens also take into account the culinary needs of students from other areas and try to replicate their regional cuisines.However, the results are not considered authentic by students from these regions.Another Jiangxi student (S60-female) reflected, ''I like spicy food.But the spicy dishes sold in the dining hall don't seem spicy to me at all.I don't like them that much, so I can't finish them.''Because canteens must control labor costs, they cannot hire chefs well versed in different regional food cultures.
Local Food Culture.The food culture of Guangzhou has its own features.For example, Cantonese people often use indigenous concepts such as ''shang shuo'' (rising fire, ) and ''re Qi'' (hot energy, ) in their daily life (Lin et al., 2022).Qi is an invisible energy or substance that determines the characteristics of food, the human body, and other material things.Some foods are categorized as cold foods that convey cold Qi, such as ''water plants, most crustaceans, certain beans (such as mung beans)'' (Chang, 1977, p. 10), while others are considered hot, such as ''oily and deep-fried food, peppery hot flavourings, fatty meat, or oily plant food'' (Chang, 1977, p. 10).By eating certain foods, the body can absorb the cold or hot Qi they contain.A healthy meal should combine cold and hot foods to attain yin-yang harmony (Chang, 1977;Lin et al., 2022) .Because of the hot weather in Guangzhou, Guangzhou people believe they get ''shang shuo'' easily and need to eat cool foods to neutralize the ubiquitous hot Qi.Such cultural beliefs influence their eating behavior, mainly in the form of eating fewer hot foods and a requirement to eat green vegetables.
Q: Chili peppers will be left over, right?A: Yes.Q: Why don't you eat chili peppers?A: Why would Cantonese people eat chili peppers?(S43-female).
Like S43, many Cantonese students leave behind parts of dishes that can cause fire, such as chili peppers and fried food.
Most of the Cantonese interviewees said that greens are a must at every meal.''Greens are a must for me, just like when I am eating at home'' (S22-female).Cantonese students have a notion that green vegetables must be leafy greens, while vegetables such as tomatoes and beans are not considered greens.Because the cost of greens is relatively low, canteen staff usually provide large portions of greens.As one interviewee said, ''The portions of greens are often too large.Often I cannot finish them'' (S54-female).The cultural fact that greens are a staple ingredient and its cheap price make green vegetables a more wasteful dish.

Health Factors
Balanced Diet.Students pay special attention to the combination of meat and vegetarian dishes to maintain healthy eating.They know that the total amount of food will be greater after they order both meat and vegetarian dishes, and they cannot finish them.However, for the sake of healthy eating, they still make sure to have both meat and vegetarian dishes for each meal.''It must be a combination of meat and vegetarian dishes.I am more concerned about healthy eating than food waste'' (S23female).
It is important to note that this desire to have a balanced diet is slightly different from the influence of local Guangdong culture, but a more general concept of health that may influence students from other regions.One student from Xinjiang said, ''Vegetables are a mustorder.I treat the green vegetables in the canteen as a way to consume vegetarian vitamins.It is important to eat more vegetables'' (S24-female).
No Overeating.While pursuing a combination of meat and vegetables, the interviewees also took care to avoid overeating.When they were already full but there was food left over, some of the interviewees forced themselves to finish their meal to avoid wasting it.Others chose not to do so and cause waste.This latter group of students tried to avoid waste, but when they had to choose between avoiding waste and avoiding overeating, they said, ''Although I know in my heart that it is not good to waste food, it is also not good if you have a too full stomach'' (S32-female).The healthy notion of not overeating took precedence over the desire for frugality.

Discussion and Conclusion
Reducing food waste is important for ensuring food security and conserving the environment in China (Cheng et al., 2012).Chinese university canteens waste a great deal of food (Cheng et al., 2018;Ma et al., 2021).Studies have mainly used quantitative research methods to explore how demographic characteristics (Ma et al., 2021;Qian et al., 2021;Qian, Li, Liu, & Wang, 2022), social and family structure (Y.Liu et al., 2016;Wu et al., 2019), and dining characteristics (Lorenz et al., 2017;Mirosa, Munro et al., 2016;Richardson et al., 2021;C. Zhao et al., 2019) influence food waste in school canteens.In this study, a qualitative research approach was used to explore the causes of food waste from the perspective of canteen consumers.
This study identified six dimensions that influence food waste in university canteens: physical, economic, psychological, social, cultural, and health.First, consistent with established research (Beausang et al., 2017;Hartmann et al., 2021;Mirosa, Munro, et al., 2016;Wu et al., 2019), poor food quality in university canteens, such as foreign objects in meals, unappealing food appearance, and poor food taste, is an important cause of waste.However, considering the number of students, for example, 12,000 students in one campus of the surveyed university, providing affordable and delicious food for such a large number of students is a big challenge.Therefore, although everyone knows that food quality is the key to reducing waste, improving food quality is not easy in the context of Chinese universities.
Second, China's economic growth and the loss of frugal habits among students also contribute to food waste.China's public universities are required to serve students from less privileged families, and providing affordable food is a natural part of the university's quest for equity.However, the group of students surveyed were born around 2000 and grew up during a period of rapid economic development in China.Many of them are well-off and have never experienced hunger, and some have been spoiled by being only children (Y.Liu et al., 2016).They have not developed the habit of being frugal, so they have little psychological pressure to waste cheap food in university canteens.This study finds that family education is important for students to develop a sense of frugality.
Third, a university is a ''small society'' where students from different geographical and cultural backgrounds live for up to 4 years.This long, intercultural and organized living situation is another main cause of food waste.During the 4 years of undergraduate study, students must eat similar dishes.Thus, even the most delicious food can bore students, leading to waste.University canteen meals are highly organized, embedded in daily busy schedule of classes, recreation, and club activities, and served during a concentrated period of time.This creates fierce competition for meals, with many students unable to complete their food orders because they are in a hurry, and others unable to order the dishes they most want to eat.Competition for meals can therefore encourage food waste.Students eat socially.Eating together can generate new sources of food waste.For example, some female students may choose to eat less to manage their feminine image.Some students chose not to finish their food to match the progress of their peers who had already finished.
Fourth, cultural differences in diet can be a source of food waste.China has a large geographical area and rich food cultures.The food culture varies greatly from region to region.For many students from other provinces, attending university is a journey to encounter different food cultures.Since the university is located in Guangdong, the canteens serve mainly Cantonese cuisine with light flavors.Such dishes fail to satisfy many students who come from a culture of preferring heavy salty and spicy food.Waste then results from unfamiliar taste.Canteen managers are also aware of this problem and tried to offer dishes from different regional food cultures, but students felt that these dishes do not have the authentic taste, which also results in waste.
Fifth, the notion of healthy eating can also cause waste.For health students usually matched meat and vegetables in order to achieve a balanced diet.In particular, Cantonese food culture emphasizes eating green leafy vegetables to neutralize internal heat and avoid fire.This health concept may lead students to order more vegetables than they can eat.When there was too much food to eat, students chose not to finish all for health reasons.
The results confirm some factors in previous studies such as food taste (Mirosa, Munro, et al., 2016;Wu et al., 2019), food appearance (Beausang et al., 2017;Hartmann et al., 2021), gender (Ma et al., 2021;Qian et al., 2021;Richardson et al., 2021), and frugality (Mirosa, Munro, et al., 2016).This study also identifies factors not previously discussed, such as food culture, health perceptions, gender impressions, meal competition, food prices, and psychological habits.More importantly, this study illustrates that food waste in university canteens has complex socio-material origins (Evans, 2012;Waitt et al., 2016).Wasteful behavior is not just a matter of attitude or lack of awareness, but is deeply rooted in university social life.

Implications
Based on the findings of this paper, several measures can be taken to reduce plate waste in university canteens.First, universities need to educate students about reducing food waste, as many are still not conscious of the environmental consequences of food waste.For example, the university in this study had a week-long ''empty plate campaign'' in which students were encouraged to eat all the food on their plates and then take pictures to post on social media.Such educational activities should be more frequent to generate a consistent and effective impact.Second, canteens need to improve the quality and taste of their food and offer authentic, competently cooked cuisines from multiple regional cultures.If this approach is too costly for the management, then the canteen could open more windows to outside vendors, using a market approach to meet diverse dietary demands.Third, the serving system and process also need further improvement, such as creating a label for each dish so that students know what ingredients are in it, offering variable portions for some dishes rather than only a standardized portion, and ensuring that the dishes served after canteen hours are still appetizing.
However, as revealed in this study, the causes of plate waste in university canteens are complicated.Food waste is embedded in specific social, material, and cultural contexts.It is difficult to address the social, cultural, and organizational causes of food waste through simple management approaches.This paper calls for more research on food waste from sociological perspectives to better understand the causes of food waste, and to develop effective measures to prevent it.

Limitations
There are some limitations for this study.First, the purpose of this paper is to identify as many factors as possible that influence college students when eating in the canteens and does not adopt a unified social theory to explain wasteful behavior.As a result, this paper addresses many dimensions, but has not explored each of them in depth.According to the findings, food waste is not caused by a single factor.We believe that assemblage theory (DeLanda, 2016) can be used to study how heterogeneous material and social factors intersect to cause wasteful outcomes.Second, only one university in Guangzhou was selected for this study, and its results cannot be generalized to explain the waste situation in all Chinese university canteens.Next, it is necessary to design a questionnaire based on the dimensions found in this paper and conduct a quantitative study for Chinese universities in general to verify the validity of these dimensions.Third, only one key manager was interviewed to understand the university's perspective on student food waste and its management.While this does not affect the study of students, interviews with more managers can get more comprehensive information and facilitate the development of management measures that can be implemented.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Figure 1 .
Figure 1.The impact factors on food waste in university canteens.

Table 1 .
Demographics of the Student Interviewees.