Higher-weight social identity as a risk and protective factor in the negative health consequences of weight stigma: a systematic review

This review explored the role of higher-weight social identity as both a risk and protective factor in the effects of weight stigma on physical and psychological well-being. Given the difficulty of combating weight stigma at the societal level [4], understanding these factors is crucial for developing targeted interventions that effectively reduce the harmful effects of weight stigma for higher-weight individuals. This review synthesised 13 studies. Across the 13 studies, seven different measures of weight stigma were used, higher-weight social identity was operationalised in five different ways, and 18 outcome variables were assessed. Thus, the research question was not suitable for a meta-analysis. Ten studies were informed by the WBSIT model and three by the social cure perspective. A general conclusion that can be drawn is that the studies support both the WBSIT and the social cure models, but results were contingent on the outcomes measured and the inclusion of moderators when evaluating the link between higher- weight social identity and well-being.

Higher-weight social identity as a risk factor

Psychological outcomes

Studies informed by WBSIT theory showed mixed results. Major et al. [11] found that higher-weight women experienced greater stress emotions after weight stigmatisation, unlike their lower-weight counterparts. However, another study [47] found no significant impact of higher-weight social identity on this relationship. Moreover, higher-weight social identity, when accompanied by weight stigma, did not exacerbate the negative emotions experienced, such as reduced self-esteem, increased anxiety, post-interaction rumination, and self-consciousness. Similarly, this social identity did not consistently exacerbate the negative impact of weight stigma on executive functioning, as observed by Blodorn et al. [47] and Hunger et al. [13].

Interestingly, two of three findings indicated that higher-weight social identity played an exacerbating role in the link between weight stigma and expectations of weight-based social rejection, while only one finding showed no impact on this outcome. Anticipated rejection has been identified as a mediator between weight stigma and psychological stress, negative emotions and reduced executive performance [13, 47]. Thus, interventions targeting rejection expectations could be implemented to prevent significant downstream psychological issues for higher-weight individuals. For instance, therapies addressing anxiety symptoms may incorporate cognitive bias modification training to address weight-based rejection expectations [48].

Furthermore, in three studies, all findings demonstrated that higher-weight social identity, combined with weight stigma, detrimentally affects outcomes related to consumption behaviours, such as individuals’ belief in their ability to control their diet and their actual tendency to do so. Notably, higher-weight women consumed more high-calorie snacks after weight stigma exposure compared to average-weight individuals [49, 50]. Since self-efficacy is crucial for long-term behavioural self-regulation among higher-weight individuals [51], interventions should prioritise promoting dietary self-efficacy. However, one study found that weight stigma’s negative consequences on alcohol use and disordered eating were worse for lower-weight individuals [37]. Given the prominence of behavioural responses to weight stigmatisation among higher-weight individuals in the WBSIT model, further research assessing these outcomes is necessary, as this study alone is insufficient.

Physical outcomes

The current review revealed that all findings from the three studies that assessed physical outcomes indicated that stigma and WBSIT can get “under the skin” to undermine a person’s physical health and their ability to fully participate in life [52]. Specifically, higher-weight social identity was found to significantly increase the harmful effects of weight stigma on physiological stress and partly explained weight stigma’s impact on functional disability among individuals identifying as higher-weight. However, as research is limited, further research in this area is needed.

Higher-weight social identity as a protective factor

Psychological outcomes

Studies informed by the social cure also showed mixed results. One study found that identification protected against the negative impact of weight stigma on self-esteem [30]. In contrast, Wellman et al. [45] reported that higher-weight social identity exacerbated the harmful impact of stigma on self-esteem, and Araiza et al. [44] similarly identified detrimental effects, linking higher-weight social identity to increased stress and unhealthy eating behaviours. Methodological differences may explain these discrepancies. Wellman et al. and Araiza et al. both used large community samples (n = 739 and n = 1257, respectively), whereas Magallares et al. [30] included 95 participants exclusively from higher-weight associations, possibly influencing their tendency to positively identify with the higher-weight group. Wellman et al. found no evidence that higher-weight social identity exacerbates the negative relationship between weight stigma and life satisfaction. However, this is one study and further research is required.

Importantly, Curll and Brown [29] found that higher perceived weight stigma was associated with stronger identification that, in turn, was associated with higher psychological distress. However, in line with their predictions, this indirect relationship was moderated by IWB. Increased identification was shown to be an effective strategy for coping with the distress associated with stigma, but only when IWB was low. This study provides valuable insights into individual factors that determine when higher-weight social identification can buffer against the harmful effects of weight stigma. It also provides support for strategies (such as, participation in online size acceptance communities) and psychosocial interventions (including group-based treatments) that aim to harness the benefits of a higher-weight social identity.

Physical outcomes

One study unexpectedly found that higher-weight social identification exacerbated the harmful effects of weight stigma on general health. However, given the limited research in this area, further studies should examine the influence of individual factors, such as levels of IWB, on these relationships.

Limitations of the studies

Most studies in this review that were guided by the WBSIT model assessed higher-weight social identity using either psychological group membership (i.e., self-perceived weight; n = 3), or sociological/assigned group membership (i.e., BMI; n = 4). Although both forms of identity are important to assess, they are conceptually and operationally different. Whereas psychological group membership reflects self-perception, sociological group membership denotes an assigned membership that may or may not correspond to one’s identity. Psychological membership is more likely to impact outcomes [8] compared to an externally assigned identity that may or may not be internalised. Acknowledging these issues, three studies [13, 37, 53] used self-perceived weight alongside BMI to assess the impact of higher-weight social identity on the harmful effects of weight stigma, all of which found significant moderation effects for both BMI and self-perceived weight. However, it remains uncertain whether mere awareness of group membership is a true measure of social identity, since social identity theory also emphasises the evaluative and affective aspects of identity [19]. Thus, it raises questions about whether a more comprehensive measure of social identity would yield different results.

To comprehensively capture higher-weight social identity, it is necessary to assess both the extent to which group membership contributes to one’s self-concept and to the positive emotional valuation of that membership [14]. Although the former was assessed in the social cure studies through measures of identity centrality, individuals’ positive feelings towards and attachment to (e.g., embracing, rejecting or neutral) the ingroup were not assessed. To better understand the complexity of the higher-weight experience and how to minimise negative outcomes of stigma, research should employ a multidimensional operationalisation of social identity that incorporates affective components, such as satisfaction with and attachment to the ingroup, in addition to identity centrality (see Leach et al. [42]). By doing so, researchers can explore the psychosocial resources available to individuals and determine how they can either facilitate effective coping with stigma or potentially intensify its negative consequences. It is essential to explore the possibility that some individuals may embrace a higher-weight identity, which is likely to result in positive psychological outcomes [54].

Furthermore, the four studies that employed the social cure approach used a correlational design, which restricted the ability to draw causal conclusions. Although the social cure approach is theoretically strong, it is possible that psychological well-being might also influence social identification and weight stigma [29]. Moreover, perceived weight stigma was assessed by reference to participants’ past stigma experiences, and so may have been vulnerable to recall bias [29]. Future research should consider longitudinal methods, such as ecological momentary assessment [55], to measure stigma experiences in real-time, reducing the potential for recall bias.

Risk of bias

In this review, 13 out of the 14 included studies were of good quality. Therefore, results were not impacted by discrepancies in quality, suggesting there was no bias in the results. However, areas for improvement by researchers include reporting response rates (n = 5 studies achieved a satisfactory response rate), and confidence intervals for main results (n = 7). None of the studies reported conducting an a priori power analysis. If studies were underpowered this could explain non-significant findings present. Future studies should report adequate information for meaningful conclusions to be drawn.

Limitations of this review

This review has some limitations. Firstly, whilst revealing important directions for future research, the heterogeneity of findings makes it challenging to conduct meta-analysis and draw definitive conclusions about the role of higher-weight social identity as a risk or protective factor in the relationship between weight stigma and well-being. Secondly, consistent reporting of effect sizes was observed for only three out of the 18 outcomes assessed (i.e., for dietary self-efficacy, cortisol reactivity, and psychological distress), limiting a comprehensive overview of the magnitude of the impact of higher-weight social identity on health outcomes. Thirdly, the scope of this review was limited by the exclusion of unpublished or grey literature, potentially introducing publication bias and excluding relevant information. Future review should include such literature to address these limitations.