Coronavirus Stress and Overeating: The Mediating Role of Anxiety and the Moderating Role of COVID-19 Burnout

Background: This study examined the mediating effect of anxiety and the moderating effect of COVID-19 burnout on the relationship between coronavirus stress and overeating among Chinese college students during the COVID-19 period. Methods: 2926 Chinese students (M age = 19.90, SD = 1.47, range = 18 - 25, 54.3% female) completed self-reported questionnaires regarding coronavirus stress, anxiety, overeating, and COVID-19 burnout. The data was analyzed using Pearson’s r correlations and moderated mediation analysis. Results: The results revealed that anxiety mediated the link between coronavirus stress and college students’ overeating. College students’ COVID-19 burnout moderated the associations between anxiety and college students’ overeating. The association between coronavirus stress and anxiety was stronger for those with higher COVID-19 burnout. Discussion and conclusion: Findings of this study demonstrated that coronavirus stress was positively related to anxiety, which in turn, was related to overeating in college students. COVID-19 burnout enhanced this effect at indirect mediation paths, suggesting that college students with greater COVID-19 burnout may be more likely to have overeating behavior. This study identied the critical factors associated with overeating; it supplies empirical support for existing theories and provides practical implications for interventions aiming to decrease Chinese college students’ overeating during COVID-19 period. of Chinese college students. However, they are limited by the cross-sectional nature of the study, meaning we cannot imply causality. We recommend that further research replicate our ndings in people with diagnosed eating disorders using a longitudinal design.

. These changes concern, among others, eating behaviors, which is often less healthy and, along with decreased levels of physical activity, leads to signi cant weight gain ( Previous research has found that overeating is a relative term. Short-term overeating is a common human habit associated with feasting and celebration (Prentice et al., 1992). Overeating becomes a health risk when it sustained over long periods. The fundamentals of the energy balance equation dictate that longterm overeating will always lead to body fat storage and obesity (Prentice et al., 1992). Overeating this article studies refers to the consumption of an energy intake that is inappropriately large for a given energy expenditure (Prentice, 2001). Overeating is not only a direct cause of obesity and eating disorders, but also an important risk factor for internalization and externalization problems such as depression, anxiety, self-harm, and substance abuse (Ye et al., 2021;Striegel-Moore & Bulik, 2007). In other countries, the COVID-19 pandemic and associated containment strategies are thought to have affect eating behaviour (Dou et al., 2020;Yang et al., 2021;Zhao et al., 2020). In Italy, which experienced a severe outbreak early in the COVID-19 pandemic, one survey found that around 53% of respondents reported eating more during lockdown and 19.5% reported weight gain (Scarmozzino, 2020). Another survey of adults in Poland, more than 40 % respondents reported eating more and 42 % respondents reported weight change (Sidor, 2020).
The Transactional Model of Stress (Lazarus & Folkman, 1984, p. 141) de ned stress as "constantly changing cognitive and behavioral efforts to manage speci c external and/or internal demands that are appraised as taxing or exceeding the resources of a person". According to the model, people respond to the same stressor differently due to individual differences including social, emotional, and psychological factors. COVID-19 has adversely affected the psychological health of individuals by leading to stress, anxiety, panic disorders, and behavioral problems (Yildirim & Arslan, 2020). A study conducted on the general public in China reported that the prevalence rates of psychological distress like stress and anxiety are substantially high (more than 25%) during COVID-19 pandemic . Stress may affect an individual's eating behavior. According to stress-induced food reward model (Adam & Epel, 2007;Dallman et al., 2003), repeating stimulation of brain reward pathways through stress, leads to neurobiological adaptations that create a feed-forward cycle promoting stress-induced overeating (Adam & Epel, 2007;Pecoraro et al., 2004). Thus, individuals who have higher coronavirus stress may be more likely to overeating.
Given this theoretical framework, the aim of the present study is to investigate whether coronavirus stress of college students is signi cantly associated with overeating and examine the potential mediating and moderating mechanisms in this association.

Anxiety as a mediator
In examining the overeating, it is important to consider the possible mediators that may play a role in decreasing the levels of overeating. In particular, anxiety may be a subsequent consequence of different levels of coronavirus stress as well as being an antecedent of overeating.
Anxiety is the natural warning system of the body indicating the imminent danger and corrective action to be taken (Hooley et al., 2016). Anxiety is a future response and often shows up when people face a new situation or when there are some signi cant changes in their lives (Beidel et al., 2014). In addition to emotional suffering, individuals with anxiety (versus individuals without) experience more health problems, poorer quality of life, and greater functional impairment (Hoffman et al., 2008). Among disorder classes, anxiety disorders account for the second highest number of disability-adjusted life years (i.e., approximately 26.8 million; Whiteford et al., 2013). Unfortunately, clinically signi cant anxiety has nearly tripled in 2020, as the severe acute respiratory syndrome coronavirus 2019 (COVID-19) pandemic has resulted in increased uncertainty and social isolation, as well as nancial and family distress (Twenge & Joiner, 2020). Prevalence of anxiety may increase due to exacerbated and sustained stress related to COVID-19 (Gallagher et al., 2020). COVID-19 stress have shown to be associated with greater anxiety (Bardeen, Gorday & Clauss, 2021). After an individual has suffered a stressful event, they will have a judgment on the severity of the crisis in terms of perception and cognition, and there will be a certain degree of reaction in physiological and psychological degrees (e.g., anxiety reactions). The more stress they perceived, the more anxious they are . In fact, several studies have shown that stress related to the COVID-19 pandemic is associated with signi cantly elevated levels of generalized anxiety ( While past studies have evidenced that anxiety predicts a diverse range of overeating (Goossens et al., 2009;Rosenbaum & White, 2016), no studies to date have directly investigated the mediating role of anxiety in the association between coronavirus stress and overeating in college students. Indeed, a range of negative subjective states (e.g., anxiety) were initiating and/or maintaining factors of different kinds of eating disorder behavior (Svaldi et al., 2019). For instance, anxiety exacerbated emotional eating and loss of control over eating in adolescents (Goossens et al., 2009). Eating has been shown to alleviate distress in individuals who lacked other, more constructive coping mechanisms to calm themselves (e.g., after experiencing life stressors or experimental manipulations that led to anxiety mood) ( (Heatherton & Baumeister, 1991). Previous research showed that stress and anxiety can increase one's impulse to eat (Macht & Simons, 2000). Previous research observed that women in Italy stated they were more prone to emotional eating during the lockdowns, and they had increased their food intake to relieve anxious . Evidence shows that anxiety as potential culprits in the appearance of overeating behaviors in normative and clinical samples (Goossens, Van & Mels, 2009; Nguyen-Rodriguez, Unger & Spruijt-Metz, 2009).
Given the uncertainty associated with the course of COVID-19, it stands to reason those students with high coronavirus stress may associate with more anxiety, which in turn may increase their risk for overeating.

COVID-19 burnout as a moderator
Although coronavirus stress may impact college students' level of overeating through the mediating role of anxiety, and individuals with different coronavirus stress respond differently to anxiety, not all college students with high level of anxiety may engage in a high level of overeating. One key buffering mechanism may be COVID-19 burnout.
The construct of burnout is de ned as a psychological syndrome caused by a prolonged response to interpersonal stressors (Maslach & Leiter, 2016). This multidimensional model of burnout highlights the importance of individual stress experience within a social context and involves the one's conception of both self and others (Maslach & Leiter, 2016).
Previous study showed that burnout seems to affect eating behavior. Women with burnout had signi cantly higher scores in overeating than those without burnout (Nina et al., 2012). Exhaustion leads to fast-food consumption which serves to counter exhaustion and in doing so, reinforces further intake of fast-food and so on (Chui et  . In other words, the role of a single risk is relatively limited, but when the risk accumulates, the effect is no longer a simple sum of the two risks, but rather a greater adaptation di culty (Bao et al., 2014;Wang et al., 2012). In other words, overeating is a defense mechanism when individuals face anxiety. Based on previous researches, when the level of college students' COVID-19 burnout is lower, as their anxiety increase, their levels of overeating tend to increase slower; when the level of college students' COVID-19 burnout is higher, as their anxiety increase, their levels of overeating tend to increase rapidly. To date, no previous studies examined whether COVID-19 as a moderator in the indirect relation between anxiety and overeating.

Present study
The purposes of this research were twofold: (a) to test whether anxiety would mediate the relation between Coronavirus stress and overeating in college students, and (b) to test whether the relations between anxiety and overeating were moderated by COVID-19 burnout. The proposed model is illustrated in Figure 1. Based on the review of literature, we posit the following hypotheses: Hypothesis 1. Anxiety will mediate the relation between Coronavirus stress and overeating.
Hypothesis 2. COVID-19 burnout will moderate the direct relations between anxiety and overeating.

Participants
A total of 2926 college students in China (M age = 19.90, SD = 1.47, range = 18 -25, 54.3% female) participated in this study. Participation in this study was entirely voluntary and no compensation was given to participants for their participation. To abide by local government policies, the study questionnaire was distributed to potential participants electronically via Survey Star (Changsha Ranxing Science and Technology, Shanghai, China) and no face-to-face contact was made. All participants consented to participation and data were anonymized. Furthermore, 37.8% of these participants were 1st year standing, 28.0% were 2nd year standing, 17.4% were 3rd year standing, and 16.8% were 4th year standing.

Coronavirus stress
The Coronavirus stress was assessed by Coronavirus Stress Measure (CSM) (Arslanet al., 2020). The scale has 5 items (e.g., how often have you felt that you were unable to control the important things in your life due to the COVID-19 pandemic?). Participants rated each item on a ve-point scale ranging from 0 (never) to 4 (always) with higher scores showing higher levels of Coronavirus stress. In this study, the internal consistency coe cient α = 0.933. Con rmatory factor analysis (CFA) suggested that the onefactor model t the data well: RMSEA =0.045, CFI = 0.999, TLI = 0.998, SRMR=0.006, which indicated that the validity of this scale was good (Brown, 2006;Mulaik & Stanley, 2009).

Overeating
The Chinese version of overeating (Luo, 2020) was measured by loss of control eating subscale of threefactor eating scale (Stunkard & Messick, 1985). This scale comprises 9 items (e.g., when I smell a delicious food, I nd it very di cult to keep from eating, even if I have just nished a meal.), and all items were limited to the time after the outbreak of the new coronavirus disease. Participants rated each item on a four-point scale ranging from 1 (very inconsistent) to 4 (very consistent) with higher scores showing higher levels of overeating. The scale has good reliability, validity and applicability in the study of Chinese population (Chen, Luo & Chen, 2020; Luo, Niu & Chen, 2020). In this study, the internal consistency coe cient α = 0.935. Con rmatory factor analysis (CFA) suggested that the one-factor model t the data well: RMSEA =0.036, CFI = 0.998, TLI = 0.990, SRMR=0.009, which indicated that the validity of this scale was good (Brown, 2006;Mulaik & Stanley, 2009).

Procedure
This study was approved by the Research Ethics Committee of the rst author's institution. We obtained consent from all participating college students before data collection. Participants were given the survey questionnaire which they provided demographic information and completed the measurements listed above.

Data analysis
The purpose of this study was to explore whether anxiety played a mediating role between the coronavirus stress and overeating of college students, and whether COVID-19 burnout played a moderating role in the indirect path between the anxiety and overeating. These research hypotheses were tested in three steps.
First, the descriptive statistics and bi-variate Pearson correlations were calculated. Second, the mediating effect of anxiety was examined by using PROCESS macro for SPSS (Model 4) (Hayes, 2017). Third, the analyses of the moderating effect of COVID-19 burnout on the indirect links between Coronavirus stress and overeating were constructed applying the PROCESS macro (Model 14). All study continuous variables were standardized, and the models utilized 5,000 resamples through bootstrapping con dence intervals (CIs) to determine whether the effects in Model 4 and Model 14 were signi cant (Hayes, 2017).

Moderated mediation effect analysis
Hypothesis 2 proposed that the indirect relationships between coronavirus stress and overeating via anxiety would be moderated by COVID-19 burnout. To examine this moderated mediation model, we used Model 14 of PROCESS macro developed by Hayes (2017). The results of parameters for three regression models are shown in Table 3. As Table 3 illustrates, the effect of coronavirus stress on overeating was signi cant (β = 0.06, p < 0.001). In addition, Table 3 also indicated that the direct association between anxiety and overeating remained signi cant (β = 0.27, p < 0.001), and the product (interaction term) of anxiety and COVID-19 burnout had a signi cant positive association with overeating (β = 0.06, p < 0.001), which suggested the effect of anxiety on overeating was moderated by COVID-19 burnout. Following the methodology from a previous study (Wang et al., 2017), we plotted predicted overeating against anxiety, separately for low and high levels of COVID-19 burnout (one SD below the mean and one SD above the mean, respectively) ( Figure 2). Simple slope test demonstrated that for college students with high levels of COVID-19 burnout, overeating was positively associated with anxiety, β = 0.21, p < 0.001. For college students with low COVID-19 burnout, overeating yielded a stronger positive association with anxiety, β = 0.33, p < 0.001. Simple slope tests demonstrated that the higher the level of COVID-19 burnout, the stronger the association between anxiety and overeating. Our results indicated that the effect of coronavirus stress on overeating was signi cant and positive among Chinese college students, and this relation can be partially explained by heightened anxiety. That is, high level of coronavirus stress increased anxiety, which increase overeating. Furthermore, the indirect relation was moderated by COVID-19 burnout in the second stage of the mediation process. These two relations became stronger for college students with high level of COVID-19 burnout.

The mediating role of anxiety
Mediation results of this study suggested that anxiety was not only an outcome of coronavirus stress but also a partial catalyst for overeating. For the rst stage of the mediation process (i.e., coronavirus stress → anxiety), this study indicated that high level of coronavirus stress promoted the activation of anxiety For the second stage of our mediation model (i.e., anxiety → overeating), the present study found that anxiety was associated with overeating. Heatherton and Baumeister (1991) suggest that overeating functions as a mechanism to escape awareness or avoid emotions. Previous research has found that overeating might provide relief or a feeling of calm (Goossens et al., 2009;Sulkowski & Dempsey, 2011). However, overeating improved participants' mood only for short time periods (Leehr, 2015). Speci cally, it has been suggested that anxiety may precede overeating which may serve as a mechanism for relieving this anxiety (Deaver et al., 2003). Other research supports overeating as a momentarily reliever of anxiety and that the shame and guilt generated by the binge then serves to reinforce this cycle (Rosenbaum & White, 2015). According to the emotional eating model (Fairburn & Wilson, 1993), binge eating behavior is due to extreme stress and an attempt to be free from unpleasant moods (Heatherton & Baumeister, 1991). Our nding supports the emotional eating model (Fairburn & Wilson, 1993), and suggests that overeating may be more likely to occur in as part of a maladaptive coping process when individuals are faced with anxiety thoughts. Further, if the above-mentioned process is in fact occurring, this suggests that individuals may have di culty appreciating the negative proximal and distal consequences of this behavior as they are focused on the perceived positive consequences of overeating (i.e., temporary blunting of anxiety) (Rosenbaum & White, 2016). In other words, the anxiety affects the individual's overeating. In summary, individuals with high coronavirus stress tend to have higher levels of anxiety which led to more overeating behaviors during the COVID-19 period.
It is also worth noting, however, that anxiety only partially mediated the association between coronavirus stress and overeating. That is, coronavirus stress remained a signi cant, direct effect of overeating even upon controlling for anxiety. The remaining direct and positive association between coronavirus stress and overeating may suggest that coronavirus stress was uniquely salient factors that could signi cantly increase the prevalence of overeating during the COVID-19 period. Thus, each of the separate paths in the mediation model was noteworthy and practical implications may be necessary at various stages of managing one's coronavirus stress to mitigate susceptibility to overeat. The society can guide college students to adopt acceptance strategies to relieve coronavirus stress. The acceptance strategy is about accepting the situation (recognizing the reality of the stressor) and learning how to live in it without actively trying to change the situation (Sameko & Guszkowska, 2016 This study reveals the in uence of psychological instinct on individual behaviors, and provides an evolutionary explanation for this path. The ndings have theoretical and practical contribution. In the context of the COVID-19 epidemic, the study deepens the theory's application and interpretation in the eld of eating behaviors in the Chinese context. By exploring the role of the cognitive tendency of coronavirus stress, we can provide evidence for the intervention of cognitive strategies for overeating; it can also reduce the possibility of overeating by decreasing the individual's anxiety; reducing the individual's COVID-19 burnout can also reduce the possibility of overeating. We can help people to establish a comprehensive understanding of the information of the COVID-19 and establish a sound social support system to reduce the COVID-19 burnout.

Limitations and future directions
Interpretation of the ndings of this study must consider the following limitations. Firstly, the fact that this study is a cross-sectional survey study does not allow inference of causality. Future studies may examine longitudinal data to infer the ndings in this study. Secondly, the measures are based on a Chinese college student sample and the extent to which results may be generalizable to other cultural contexts is limited. Future studies may collect data from multiple informants (e.g., teacher, peer, or parents) across different cultures to further examine the robustness of our ndings. Additionally, the current study did not collect information regarding students' majors nor family socioeconomic status. Future studies may also examine the robustness of the model presented in this paper in other populations that may be exposed to qualitatively different coronavirus stressors in both frequency and intensity (e.g., frontline healthcare workers), and longitudinal studies of eating behaviour and other behavioural risk factors are needed to understand both short-term and long-term mental and physical health impacts

Conclusion
Although further replication and extensions are needed, this study is an important step in unpacking how coronavirus stress relate to overeating of Chinese college students. Because anxiety served as one potential mechanism by which coronavirus stress was associated with overeating, it remains important to address anxiety directly or intervene in a manner that reduces the impact of anxiety on overeating. At the same time, it is necessary to reduce the level of individual COVID-19 burnout. This study was approved by the Research Ethics Committee of the rst author's institution. We obtained consent from all participating college students before data collection. Participants were given the survey questionnaire where they provided demographic information and completed the measurements listed above. The ethics review approval code is IRB-JXNU-PSY-2020002.
-Consent for publication N/A.

-Availability of supporting data
This study data is available to researchers.

-Competing interests
All authors report no con icts of interest. -Funding Jiangxi' Social Science Planning Project (18JY09) -Authors' contributions RNW and BJY conceptualized the study. RNW completed the statistical analyses. BJY, RNW and QY contributed to the drafting and revising of the manuscript. All authors read and approved the nal manuscript. -Acknowledgements Thanks to everyone who helped during the research. Figure 1 The proposed moderated mediation model.