Household food waste and theory of planned behavior: A systematic review and meta-analysis

The darker side of food behavior is that millions of tons of food have been shown the doors of garbage. Therefore, food waste behavior needs an eye to look upon. The purpose of this research is to inculcate the concept of systematic literature review along with meta-analysis in order to examine the Theory of Planned Behavior (TPB) with respect to food waste behavior. The methodology includes Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) that is conducted for the identification, screening, and inclusion of studies. In all, twenty-six independent studies with (N = 13373) met the inclusion criteria. For validating the related literature, random-effects meta-analysis has been applied for ascertaining the average correlation among the variables. More specifically, the present study also examines the sub-group analysis effect among TPB variables. The findings reveal that the strongest association was observed between Attitude and Intention followed by Subjective Norm (SN) and Intention (INT), Perceived Behavioral Control (PBC) and Intention, and Intention and Behavior. Furthermore, the subgroup analysis using multi-cultural groups explores the highest composite correlation in the case of other cultural groups that included countries like Canada. The outcomes of the present study seek to serve in the best interest of households, event management stakeholders, and food policy makers.


Introduction
The concept of food waste is a matter of concern from the very past.In fact, the term 'food' is a blessing from God that is continuously showering upon human genesis.It is a well-known saying that 'Human being is by nature gregarious and community or group existence is one of the most enduring features of human being on this planet (Deneulin and Townsend, 2007).Further, this food is the pivot that binds community on different clusters whether it is a social celebration, corporate gathering, birth celebration, funeral rituals and others (Vermeulen et al., 2020).In fact, this all human struggle is for appetite and this very appetite is served with food itself (Weis and Weis, 2007).In addition to it, for a healthy life, nutritional value content is required which can only be supplemented through food.Not only this, the food waste of household is one the core challenges that deters the supportability of modern food set-up worldwide (Annunziata et al., 2022;Liao et al., 2018).The issues of food wastage in respect of social and environmental impacts remains untouched or very limited and in relation to food waste behavior (Blešić et al., 2021;Szakos et al., 2021).
Food plays an important part in our lives, not just in terms of supplying fuel, nutrients, and sustenance, but also in terms of forming the basis of many of our social connections (White et al., 2009).Household food waste has become the fulcrum of food series that fetches attains from its various conceptual stakeholders and variables (Ferro et al.,2022).Consequently, because of our biological requirement to get, make, and consume food so as to survive, a portion of the food that is meant to be consumed by humans is thrown away as a waste.Unfortunately, 1/3 of all foods manufactured in the world is disposed or wasted, costing $400 billion per year (Nixon, 2015).As stated by FAO (the Food and Agriculture Organization) in 2016, nearly 1.3 billion tons of food provided for consumption by human beings is thrown away or dumped every annum.Food losses and waste among developed nations total nearly $680 billion, while in developing nations they total nearly $310 billion (FAO, 2016).According to several surveys, food waste accounts for more than a 1/3rd of the country's yearly production.Food waste effects both the environment and the economy adversely, and the management of discarded food require costs within the energy and water sectors (Buzby et al., 2014;Reisch et al., 2013;Szakos et al., 2021).
The darker side of this aspect is that millions of tons of food has been shown the doors of garbage.Hence, this food waste behavior needs an eye to look upon.Losses and wastage of food are the issue in question, resulting in worldwide shortages of food and other severe repercussions (Lipinski et al., 2013).In the Indian backdrop, this problem is rapidly growing that indicates a loss of usefulness and ine cient food management, which has signi cant economic, environmental, and social consequences.On the other hand, improving this ine ciency has the potential to transform these negative consequences into societal gains.
In India, almost 67 million tons of foods are thrown away each year, valued at more than $14 billion (Nawaz et al., 2016).According to an article in Business today, (Kapoor, 2021), in 2019, Indian homes wasted food accounted for 7.4% of the total 931 million tons worldwide.Each year, the average household wastes 74 kg of food.It was lower in India, at 50 kilograms per household (68.8 million tons a year).Moreover, this problem is rapidly growing in severity in India.Consumers, despite their typically unfavorable attitude towards wastage of food, frequently seek objectives which can sabotage their efforts to prevent the loss of food.Determining the objectives which restrict customers' desire to avoid food waste is necessary for the development of effective public policy and retail strategies to restrict or minimize household food waste.
The important note here to mention is that there exist very few amounts of literature that investigates Theory of Planned Behavior in the context of food waste through meta -analysis.So far limited knowledge of author is concerned, till date, no multi-group analysis study was found backing with culture wise.The culture pattern is very essential to get acquainted as the food consumption pattern varies signi cantly in different continents of the world.In the respect of meta-analysis, there was a lacuna of study which conducted sub group analysis on the basis of sample size.Methodologically, sample size differences create a standard amount of difference in results too.These gaps induced the researchers to work upon.RQ1: How TBP constructs are interrelated with each other?RQ2: How different culture varies in context to food waste behavior?RQ3: Is there any signi cant difference of sample size on food waste behavior?
To address the crucial literature gap and research queries, the following research objectives are outlined.

1.
To analyze the association among TPB constructs in relation to food waste behavior.2. To examine the difference in culture in context to food waste behavior.
3. To assess the sample size effect in relation to food waste behavior Thus, this timely research work endeavors to contribute the extant literature by addressing the crucial gap therefore a systematic literature review has been conducted by the researchers on the ow and identi cation of the paper with the help of PRISMA.We conducted sub group analysis on the basis of culture wise and sample size wise by systematically reporting correlation values of each and every construct underlying through meta essentials.Apart from this, the study also reported the correlation values of each and every construct interrelation of TPB, construct name of each and every study, behavior of each and every reported study and sample details of each & every study.
Based upon ongoing description, the current study facilitates a meta-analytic integration of research on food waste and TPB.In general, the current study emphasizes upon assessing the strength of the association between food waste with different TPB constructs.In addition to this, the present study will also examine the sub-group analysis effect for those TPB constructs hypothesized to have direct relation with food waste behavior, intention, Attitude, Subjective Norms and Perceived Behavioral Control.The reported sub-group analysis effect will involve multi-cultural groups and relative sample size.These differences have important practical implications for food policy initiatives.

Theory Of Planned Behaviour And Food Waste Behavior
It is a standard saying that scienti cally every action has equal and opposite reaction.In other words, an action is created in relation to any de ned stimuli that is more speci cally de ned as behavior.The biggest association with the term behavior is that it is highly unpredictable.Moreover, understanding human behavior aspect is a cumbersome one but not impossible.This needs to be addressed with several conceptual dimensions.In this regard, a theoretical foundation with systematic valid reasoning needs to get proposed.Keeping this in mind, Theory of Reasoned Action or Reasoned Action Theory (Ajzen, 1975) followed by pervasive Theory of Planned Behavior or TPB (Ajzen, 1991).The advanced theory basically deals with the constructs (i.e.Attitude, Subjective Norms and Perceived Behavioral Control) that extracts a constructive meaning to the stated behavior (Jaiswal et al., 2022).The said elements of this theory jointly together create a model that suggests cognitive self-regulation plays a crucial role.
The TPB (Theory of Planned Behaviour) developed by Icek Ajzen in 1991, is individual paradigm that deals with behavioural intention.This theory is a conceptual extension of Fishbone and Ajzen (1975) Theory of Reasoned Action without "Perceived Behavioural Control "It is now regarded to be bene cial for predicting human behaviour (Tommasetti et al., 2018).In 1980, TPB was formed so as to forecast an individual's behavior to behave in a speci c action at a particular phase as well as locality.The hypothesis was made to include all human behaviours that are related to self-control.This model is built around the concept of behavioural intent.One's perception of the possibility that perhaps the behaviour can produce the intended outcome, and also one's subjective judgment of the bene ts and risks of that consequence, in uence behavioural intentions.
The TPB was used to study consumer decision-making, making in the disciplines of sustainability (Jaiswal et al., 2022), notably waste minimization and recycling, as well as food-related behaviour (Jaiswal and Singh, 2018;Mondéjar-Jiménez et al., 2016;Tommasetti et al., 2018).In recent times, the TPB has been commonly used to forecast and describe ecological performance.Further, the Attitude, Subjective Norm (SN) and Perceived Behavioral Control (PBC) cumulatively carries a standard bearing on food waste reduction based on intention (Wang et al.,2022).On the same lines, another author concludes that personal attitudes and perceived behavioral control (PBC) directly hits food loss behavior (Blešić et al., 2021).The ndings of investigations have typically validated the TPB's usefulness in predicting intention.However, there is indication that, as required by the model, intentions can assist in forecasting of behavior related to the atmosphere (Graham-Rowe et al., 2015; Jaiswal et al., 2022).
The conceptual framework is seen to be helpful in dealing with the complexities of social human behaviour and can be used as a beginning point for change.With a topic as complicated as sustainability, which is highly volatile in terms of social concerns as well as human behaviour, the theory appears to be a viable choice for understanding decision-making processes in this subject.According to Ajzen (1991), each of these aspects of conduct (attitude toward behaviour, perception of behaviour control, subjective norm, and intention) reveals a different aspect of conduct.People's intentions to do something are strengthened once they have a favourable attitude toward the behaviour (Jaiswal et al., 2021), as stated by the TPB, consider that prominent people want them to act in a con dent approach, and assume that they have enough power to engage in the desired behaviour.Almost all of these structures are a re ection of a person's personal beliefs.
For example, whether or not a person believes important people want them to indulge in a particular behaviour does not always correspond to what other key people really want when directly asked.The TPB, on the other hand, argues that perception is much more important than facts in determining behaviour.Socio-demographic characteristics are found to be vital estimators of behaviors associated to food.In fact, the ndings provide the base platform for establishing policy measures in consonance with the determinants of household food wastage behaviors particularly in developing nations (Abouhatab et al., 2022).Some of the reported behaviors are habits, attitude, perceived behavioral control and intention to reduce food waste carries vitality in describing reduction in food waste behaviors and a mere habit and perceived behavioral control (PBC) can become a possible avenue for designing instructional policies (Niha et al., 2022).
In addition to it, in the context of meta-analysis, it was observed that intention accounted approximately for 27% of the variance of food waste behaviours (Bamberg and Möser, 2007).(Graham-Rowe et al., 2015) stated that TPB has ability to anticipate reduction in household food waste.As per the result of extended model explained 64% variance of intention with attitude, Perceived Behavioral Control, Subjective Norms, self-identity and anticipated regret found strong linear predictors.

Methods
The nitty-gritty of particular systematic review was communicated through Preferred Reporting Items for Systematic Reviews & in accordance with Meta-Analyses framework.This current study involves the resources of mainly secondary data nature.

Selection criteria/bases
In relation to PRISMA, the PICOS (i.e.population, intervention, comparison, outcome & study design) approach is applied for selection of studies (Mcdermott et al.,2015).The works mainly in English that mainly talks about TPB (Ajzen, 1991) were included.Further, the studies did not meet the inclusion criteria where food waste behavior was not reported.In addition, the studies where absence of generalized population, different sorts of participants' intervention and comparison between conditions took place were excluded.In adherence to the TPB theoretical model, the studies should carry at least reported correlations among following outcomes i.e.Attitude with Intention, Subjective Norms with Intention, Perceived Behavioral Control with Intention, Intention with Behavior & Perceived Behavioral Control with Behavior.
Lastly, any design on quantitative study was given consideration provided that the other stated inclusion criteria were hit.

Study identi cation
The probe is made collectively by both the authors of the current study jointly through two standard databases i.e. google scholar and EBSCO using the keywords like Role of Food waste in TPB, TPB and systematic literature review, Food waste behavior, TPB: An extended model in order to extract and sync the different number of eligible studies.The total searches were conducted during January-April 2022.Reference lists of total number of studies identi ed for inclusion in the reference panel of vital systematic Further, all the researchers of the current study (SKS, AM & SS), pre-screened the whole databases that contained all the heads and abstracts for direct inclusion in the study.Data from every study under investigation was extracted mainly by one researcher (AM), the accuracy of which was ascertained by SKS (the other author) and guided by (SS).Any reported discrepancies during the course were resolved unanimously.

Data extraction
Apart from extracted and calculated correlation data, data were extracted and coded for multi-cultural groups and respective sample size with respect to subgroup analysis.The multi-cultural groups were coded into three important categories where 1 = Asian respondents, 2 = European respondents and 3 = others/rest of the world.On the same lines, respective sample size was coded into 2 main categories i.e. 1= >=400 and 2 = < 400.Further, the extracted and coded data were put into specially framed electronic database.

Analysis And Results
The analysis was of the current study was performed on Meta essentials excel interface (Suurmond et al., 2017) where pooled mean effect size (r + ) and subgroup analysis was held.The current study also tested the

Identi cation stage
The electronic database search strategy from two important terminals i.e. google scholar and EBSCO retrieved 213 records.These 213 records comprise of journal articles, thesis, book & conference proceedings (Nejad, 2005;Nejad et al., 2004).Out of these 213 records, 190 searches come from google scholar and rest 23 is from EBSCO source.In part 2 of identi cation stage, 10 duplicate records were removed.These all procedures of PRISMA were facilitated through Endnote software.

Screening stage
Initially, 203 records entered into screening stage and out of which 103 record were excluded because food waste variable along with TPB theoretical framework were not existed.Further, this difference of 100 went into the category of 'reports sought for retrieval'.Out of this, 21 reports went into the category 'reports not retrieved' as the authors did not nd the access to reports.This further created a difference of 79 which went into the column 'reports assessed for eligibility'.Out of this, 53 reports got excluded under three valid reasons head.Under Reason 1, 18 reports got excluded because correlation was not reported in the mentioned studies.Under reason 2, 12 reports got excluded because behavior was not explained.Finally, under reason 3, 23 reports got excluded because other variables were explained.

Inclusion stage
Finally, a total of 26 studies met the inclusion criteria (Fig. 2).The relevant data were extracted from either journal article as suitable or thesis.The twenty-six studies were therefore included with a total n of 13373.
The complete details of the screening process can be seen in the PRISMA ow-chart (Fig. 1)._______Insert Fig. 1_______ _______Insert Fig. 2_______ 4

.2 Description of included data
The allocation of variables uprooted from every le have been xed diligently under meta-analysis le.Most of the studies under inclusion criteria were held on Asian cultural groups (n = 14), followed by European cultural groups (n = 8) and remainder comes under the category 'other cultural group' (n = 4).The reported sample size ranged between 53 and 2004.The twenty-six articles that ful lled the inclusion criteria were published during the phase of 2014-2022.The overall sample size of the study reported under the inclusion criteria is 13373.

Direct relation of TPB variables with Intention (INT.) & Food Waste Behavior (FWB)
From the Table1, it clearly reveals the random-effects average correlation among TPB variables.The extracted data study was analyzed on meta essentials interface of excel and we found that TPB variables carries association amongst stated variables.Primarily, the association was tested between attitude and intention (r + = 0.44), followed by SN-Intention (r + = 0.36), PBC-Intention (r + = 0.34), Intention-Behavior (r + = 0.09) and PBC-Behavior (r + = 0.08).The nal observed picture revealed that there exist low and moderate association among the TPB variables of studies.The signi cant reason behind low and moderate association among TPB variables is higher I 2 (i.e. a higher I 2 re ects a high heterogeneity) along with a higher Q.This signi cant variation paved the way towards subgroup analysis.Forest Plot for each and every association can be observed.

Subgroup analysis: Multi-cultural groups
The above table 2 talks about different cultural groups of the studies under inclusion as a part of subgroup analysis.The subgroups are further trifurcated into 3 important categories.The studies under inclusion criteria were held on Asian cultural groups (n = 14), followed by European cultural groups (n = 8) and remainder comes under the category 'other cultural group' (n = 4).The reported sample size ranged between 53 and 2004.After conducting analysis on meta essentials, primarily it was found that the nest association among the variables of the studies in case of Asian cultural groups (i.e.Attitude-Intention (r + 0.37), SN-Intention (r + 0.33), PBC-Intention (r + 0.23), Intention-Behavior (r + 0.25), PBC-Behavior (r + 0.27).
_______Insert Table .2_______ Further, the signi cant difference was seen in between PBC-Behavior & Intention-Behavior among the three mentioned cultural subgroups.The reported correlation value in case of PBC-Behavior subgroups are (r + 0.25), (r+ -0.16) & (r + 0.02).Whereas in case of Intention-Behavior subgroups, the reported correlation values are (r + 0.27), (r+ -0.18) & (r + 0.00).Apart from this, no signi cant difference was found among other TPB variables subgroups.One important outcome of table 2 is that the min and max values of correlation is said to be in other cultural groups (i.e.r + 0.00 and 0.55).

Subgroup analysis: Sample size groups
The table no. 3 talks about respective sample size of two subgroups.Further, the analysis was done on meta essentials where one subgroup is of > = 400 participants whereas the other subgroup formed is of < 400 participants.One of the major analysis of table which was conducted jointly by the authors is that on increase in sample size, the association of stated TPB variables gets strong.The reported correlation in case of Attitude-Intention increased to (r + 0.39 to r + 0.47), followed by SN-Intention (r + 0.32 to r + 0.35), PBC-Intention (r + 0.30 to r + 0.38), Intention-Behavior (r + -0.02 to r + 0.30) and PBC-Behavior (r + -0.07 to r + 0.32).
Further, the extension of analysis reveals that the highest reported association took place between Attitude-Intention (r + 0.47).The signi cant difference was observed in case of Intention-Behavior (r + -0.02 to r + 0.30) and PBC-Behavior (r + -0.07 to r + 0.32 Further, it was observed that intentions were most ideally and suitably correlated with attitudes, followed by SN and PBC.The strongest association of behavior was reported with intention followed by PBC.This is because Perceived Behavioral Control with respect to food wastage was related with food planning as well as the shopping routines (Chen, 2022).The present review provides signi cant information with respect to subgroup variables.Further, in case of subgroup analysis the standard association between intentionbehavior and PBC-behavior were found to alter signi cantly in respect to other TPB variables.
In case of subgroup analysis, the healthiest association among the respective TPB variables was observed in case Asian culture, followed by other cultural groups and European cultural groups.The societal, economic and ecological connect of wasting food is thus a massive challenge in Asia.It is evident developing countries are confronting social malice like food waste management more than the developed ones (Thi et al.,2015).The developing countries are facing challenges on account different issues like environmental problems and sanitary problems (Heidari et al., 2020;Thi et al.,2015).Following the issue of food wastage to the different culture and environment in all, proper and in-depth analysis of the related strategies is required, particularly in Asia where this problem is complex issue (Joshi and Viswanathan, 2019).One of the studies suggested that participants size estimated the food waste behavior particularly in European culture (Grasso et al.,2019).The signi cant deviation in this very subgroup analysis belongs to Intention-behavior and PBC-behavior.As per TPB, PBC directly impacts the behavior up to the level that connects standard control (Ajzen and Madden, 1986).
The major point of concern is that on increase in sample size, the association of following stated TPB variables gets strong.The reported correlation in case of Attitude-Intention is found to be maximum and highest with respect to remaining others.The signi cant difference was observed in case of Intention-Behavior and PBC-Behavior.Further, no signi cant difference was found among other TPB variables subgroups.The Interclass Correlation Coe cient (ICC) is a kind of statistical estimate which deals with degree of reliability, consistency and stability between quantitative variables.Furthermore, it is important here to note that as the sample size increases, the association between variables tends to increase (Bartko, 1966;Bartko, 1976;Hunt, 1986;Shrout and Fleiss, 1979;Taylor, 2010).

Research implications
The current study emphasized upon two vital theoretical contributions in order to provide core strength to the existing theory.Firstly, the multi-culture subgroup analysis was performed in order to determine the association among different TPB constructs.Secondly, the sample size subgroup analysis was conducted in order to ascertain the relation among various TPB constructs.The reported association was tested amongst Attitude-Intention, Subjective Norms-Intention, Perceived Behavioral Control-Intention, Intention- Behavior & Perceived Behavioral Control-Behavior.
The outcomes of the current study provide an in-depth understanding of the factors of food waste behavior which is of utmost value for households, event management stakeholders and food policy makers.Yet another contribution will be dispersing of social awareness among different sections of the society that will assist in putting the food waste barometer on a lower side.The study will also have paved the way towards formation of healthy and sustainable consumption behavior.It is worth mentioning to note here that Theory of Planned Behavior or TPB sets out the expeditious conceptual foundations for explaining the food waste behavior to a signi cant degree of extent.The researchers shall also inculcate some additional variables as an extension of TPB and test the explanatory power of extended theoretical framework in comparison to basic framework.
In context with current ndings, the studies that met the inclusion criteria were not enough to extract signi cant differences among different subgroups platforms.One strong reason here is that the relationships explained in terms of correlation do not always cover to those uncovered in studies under experiment (Sheeran et al., 2014).In all, the studies have somehow portrayed the association among the stated TPB variables under different subgroups case.This current study will add signi cant contribution in existing pool of literature related with food waste and associated behaviors.

Conclusion And Future Research
Food has been treated one of the nest blessings of God from ages.During the course, the wastage of food has become a common practice worldwide.In order to felicitate this study, there must be standard practice worldwide as to not to waste the food as and when served right from agro-waste to household waste.Our central nding is that the TPB variables underlying in the study have low to medium associations with respect to intention and food waste behavior and will therefore insist program makers with lexicon for framing effective interventions.The results insisted upon increment in sample size in determining the overall effectiveness and associations among stated TPB variables.Finally, in the context of multi culture subgroups, the nest association between intention and food waste behavior was seen in Asian culture.It is because of the fact food is the center of gravity among different sorts of social gatherings in respect to other culture.
The foundation effect of the current study includes the standard probe policy where journal articles, thesis and dissertation through diligent screening and inclusion process to frame the design, procedures and reporting of meta-analysis (Moher et al.,2009b).Yet another strength here to add upon is that inclusion of studies took place through standard reporting format i.e.PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analyses).One more important addition here is that instead of including samples studies of homogenous nature, the reported heterogeneity stood high for all sorts of association and analysis (Mcdermott et al.,2015).One important strong point to support this study is that even with such limited number of inclusion studies, it became possible to extract association among all stated TPB variables.Last but not the least, the small number of sample studies limited researcher potential to extract signi cant differences in all elements of subgroup analysis.
Hence, there is a dire need of improvisation required with food waste culture.At the end, the future research must get centered upon inclusion of a greater number of samples in subgroup analysis and also exploring some novel factors which carries a lion's share stake in the existing theoretical construct.
heterogeneity across various dimensions by employing Q (a signi cant result indicates vital heterogeneity & I 2 (values of 25%, 50% and 75% represented low, moderate and high heterogeneity respectively (Mcdermott et al.,2015).

Figure 1 See
Figure 1

Table 1
n = number of participants, k = number of effect sizes included in the analysis, CI = 95% con dence interval, Q and I 2 = tests of heterogeneity, r + = random average correlation Table-2: Random -effects average correlation & heterogeneity statistics by various culture wise members n = number of participants, k = number of effect sizes included in the analysis, CI = 95% con dence interval, I 2= tests of heterogeneity, r + = random effects average correlation.

Table 3 :
Random -effects average correlation & heterogeneity statistics through sample size wise (Sample Size >=400 and Sample Size < 400) of participants (Wang et al., 2022)1998) difference was found among other TPB waste is a common phenomenon that is observed in every stage of supply chain but the ratio becomes highest when consumers waste it(Aktas et al., 2018).From the theoretical and base foundation point of view, the outcomes of present study re ect the importance of adding literatures on additional predictor variables with respect to utility based TPB model(Conner & Armitage 1998).The present study the lead to determine the relations between TPB & food waste behavior.It is so because different variables of Planned Behavior Theory (TPB) like attitude with respect to food wastage, Subjective Norms (SN) and Perceived Behavioral Control (PBC) have bearing on intention to reduce food waste and not only this, food waste behavior is also vitally affected by intention to reduce food waste(Wang et al., 2022). Food