Introduction

For over 50 years, researchers have documented weight bias,Footnote 1 known as the negative attitudes and beliefs and discrimination toward individuals who live with obesity [1,2,3]. Weight bias in kindergarten to grade 12 (K-12) schools most often manifests as children and adolescents with obesity being victims of direct forms of aggression such as verbal teasing/bullying (e.g., verbal harassment, name-calling, fat jokes), physical bullying (e.g., hitting, pushing, kicking, shoving), or indirect forms like relational bullying (e.g., social exclusion, being the subject of rumors) due to their body weight [4,5,6]. For children and adolescents, schools are a common setting for experiences of weight bias, as peers, teachers, and other school professionals can also hold negative attitudes and beliefs about individuals with obesity [4, 7]. Adolescents living with obesity have reported that the school context is the most common place for weight-based teasing to occur [8] and that they are much more likely to be victims of bullying than their counterparts with “normal” weights [9, 10]. In the same period of time that childhood obesity has come to be labeled an epidemic (i.e., the last 40 years), weight bias against children has increased dramatically by 41% [11].

Educational settings have often been seen as important sites to “prevent” or “combat” obesity [12]. However, actions taken in efforts to improve the health of students may be misleading, misguided, and even potentially harmful [12]. Weight bias in schools begins early in childhood and becomes more prevalent in adolescence, with the largest children at the highest risk of being bullied [7] regardless of gender, race, social skills, or academic achievement [13]. The impact of weight bias extends through from grade school to postsecondary educational settings [14]. Being on the receiving end of weight bias has serious psychosocial and physical consequences in children and youth including increased risk of depression, anxiety, social isolation, substance use, suicidal thoughts, poor body image, low self-esteem, unhealthy eating behaviors, binge eating, decreased physical activity, and worsening of obesity [2, 15]. Despite the serious consequences of weight bias, students with obesity have reported that policies intended to create safe environments in educational settings have not been applied or enforced in relation to weight-based discrimination [16]. While weight bias continues to be a problem in educational spaces, the literature on the topic must be synthesized to help guide future interventions, policies, and practices to address weight bias in educational settings.

The purpose of this systematic review was to synthesize the available evidence on the prevalence of weight bias and its impact on the educational experiences and the health of students in K-12 and postsecondary settings. While similar previous reviews of weight bias literature have been conducted, these reviews have focused on the broad nature of weight bias experienced by children and youth, not limited to an educational setting [17, 18], how children and youth cope with weight bias in physical education settings specifically [19], and associations between childhood obesity and academic achievement [20]. The current review adds to this literature by providing a review of original research specific to the occurrence of weight bias in educational settings, but broadens the review to all educationally based research, rather than research conducted solely within physical education. Specifically, this review aimed to examine (1) the prevalence of weight bias within educational settings, (2) the impact of weight bias within these settings on the health or peer relationships of students, (3) teachers’ or pre-service teachers’ attitudes and beliefs about students with obesity, and (4) weight bias reduction interventions conducted with students, teachers, or pre-service teachers in educational settings.

Method

We followed the systematic review protocol outlined in the Cochrane Handbook for Systematic Reviews of Interventions [21]. We report our findings in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [22] statement presented in Fig. 1.

Fig. 1
figure 1

PRISMA diagram overview selection of studies for review

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Data Sources

A health sciences librarian (K.A.H.) developed the search strategy based on three main concepts: (i) weight bias/stigma, (ii) obesity/overweight, and (iii) education. Keywords were generated for each of the three main concepts by reviewing subject indexing and key terms, and by reviewing search strategies from similar systematic reviews in weight bias literature [2, 23,24,25]. The search strategy was pre-tested to ensure that relevant known studies were retrieved. Keywords were the same for each database, and subject headings were determined by the controlled vocabulary for each database. The MEDLINE search strategy can be found in the Appendix.

The search strategy was limited to English and from the publication date of 2000 onwards. Searches were conducted in eight databases (OVID databases: Medline, EMBASE, PsycINFO, Cochrane Central Register of Controlled Trials; and EbscoHost databases: CINAHL SocINDEX, Education Research Complete, ERIC). The initial search was conducted in December 2016, and was updated in May 2018. Studies were included if they were original research articles that aimed to address our research objectives outlined above and were published in English. Commentaries, editorials, literature reviews, letters, conference abstracts, theses, and gray literature were excluded. Furthermore, articles were excluded if (i) they examined the effects of an obesity prevention program in schools where weight bias was not measured, (ii) research conducted with school-aged or postsecondary samples that investigated only the prevalence of weight bias as a proxy for the prevalence of weight bias in the general population rather than with the purpose of examining the impact of these attitudes on educational experiences, and/or (iii) the article did not examine educational attainment based on body weight or was not related to weight bias within an educational setting.

The search yielded a total of 13,241 abstracts. After the removal of duplicates (n = 4918) and inter-rater training, two authors (S.N. and A.I.) independently screened the remaining 8323 titles/abstracts and reached consensus through discussion, when required. Given the large quantity of records identified through the search, two research assistants (I.B. and D. L.) were recruited and trained to assist with the remaining phases of the screening process. The 207 papers that met the inclusion criteria in the title/abstract screening were then reviewed in full text for eligibility (by S.N. and I.B. or A.I. and D.L.). This phase resulted in 45 articles selected to be included in the review. Working independently, all four reviewers (S.N. and I.B. or A.I. and D.L.) analyzed and summarized the 45 studies, which were verified by S.N and A.I. for the final inclusion.

Results

Study Characteristics

Study characteristics are described in Table 1. Of the 45 papers included in this review, 18 reported samples of students (i.e., K-12, postsecondary), 16 were samples of teachers, and 11 described samples of pre-service teachers (i.e., postsecondary Bachelor of Education students). Regarding educational settings, 41 papers examined weight bias in the K-12 setting, 3 were conducted in a postsecondary setting, and 1 paper was a retroactive study with adults on past experiences in K-12 physical education (PE). There were 37 quantitative studies and 8 qualitative studies. The majority of studies examined negative attitudes toward students with obesity (i.e., weight bias) and its prevalence among peers, teachers, and pre-service teachers (n = 28). The remaining studies examined the impact of weight-based victimization on student well-being (n = 5), the effectiveness of weight bias reduction interventions (n = 6), students’ preferred sources of support for weight bias at school (n = 2), teacher behavior toward students with obesity (n = 2), and student experiences with weight bias in K-12 physical education (PE) classes (n = 2).

Table 1 Characteristics of Studies that Met the Inclusion Criteria
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K-12 and Postsecondary Student Samples (n = 18)

Research with student samples examined the prevalence and impact of weight bias, preferred supports for student victims of weight bias, experiences specific to PE, and a school-based intervention aimed to reduce weight bias among children and adolescents. Papers included in this section represent research that investigated the impact of weight bias on students in a K-12 or postsecondary educational setting.

Prevalence of Weight Bias

Eight studies examined the prevalence of weight bias with samples of children and adolescents [7, 14, 26,27,28,29,30,31]. The results of these studies suggest that children or adolescents with obesity are more likely to be bullied than students without obesity [13, 29] and that students with obesity are likely to experience threats, physical victimization, and social exclusion in addition to weight-based teasing [7, 26]. Among a sample of adolescents with obesity, 71% indicated experiencing weight-based victimization (e.g., teasing) at school within the previous year [30], which is consistent with a sample of adolescent peers, of whom 85–92% reported witnessing weight-based teasing at school [7]. Research examining peer relations and friendship networks demonstrated that, as body weight increases, children and youth are less likely to be identified as friends [27], are perceived as less popular, more sensitive, less attractive, and less athletically skilled [31], and that these differences do not differ for students based on racial or ethnic diversity [28].

Impact of Weight Bias on Students’ Health and Well-being

Five studies investigated the impact of weight-based victimization on students with regard to physical and psychological well-being [8, 32,33,34, 35•]. Results from these studies indicated that, within K-12 schools, children and adolescents who experienced weight-based teasing felt self-conscious, angry, and unappreciated by their peers as well as had low self-esteem and increased symptoms of depression compared to peers who were not teased for their weight [8, 32, 33]. Weight-based victimization was also associated with a variety of positive (e.g., seeking social support, utilization of stress reduction strategies) and negative (e.g., disengagement, avoidance, confrontation) coping strategies [34] in these settings. Within postsecondary education, a sample of medical students with overweight/obesity who perceived experiences of weight discrimination reported lower overall health, lower body esteem, and greater loneliness, and were more likely to report using drugs or alcohol as a coping strategy compared to medical students without overweight/obesity [35•].

Weight-Based Victimization Support

Two studies examined children and youth preferences for support related to weight-based victimization [36, 37]. In a study about preferred sources of support, youth indicated they would most want their friends to intervene (66%), followed by their peers (58%), teachers (55%), physical education teachers (44%), and parents (43%) [37]. Another study examined the perspectives of children, school staff, and parents to identify school-based support strategies, including creating a school environment that (1) discourages bullying, and promotes (2) social support, (3) self-esteem, and (4) healthy eating and regular physical activity for children of all sizes [36].

Experiences with Weight Bias in K-12 Physical Education

Two papers examined the impact of weight bias on experiences within PE in K-12 schools. Wiltshire, Lee, and Evans’ [38] qualitative study found that students did not want to “stand out as the bigger one” (p. 553) and that their engagement was dependent upon physical ability. Students with obesity who were regarded as good at sports, by self or others, engaged in activity at school, while those not regarded as good at sports did not [38]. One study retrospectively investigated childhood experiences of PE among a sample of adults who identified as having overweight/obesity [39]. Qualitative interviews were conducted with 15 adults, from which themes emerged related to participant’s perceived inability to form positive relationships with their bodies in PE, as well as experiences of shame associated with public weighing in PE classes.

Student Weight Bias Reduction Intervention

One study investigated the effects of a weight bias reduction intervention conducted among a sample of grade 4–6 students aimed at preventing weight-based teasing as well as unhealthy weight-control behaviors [40]. This multi-faceted intervention included an after-school program and theater program, as well as school and family environment components, and led to decreased reports of weight-based teasing among students.

Teacher (n = 16) and Pre-Service Teacher (n = 11) Samples

Papers included in this section are comprised of samples of both currently practicing (i.e., in-service) as well as pre-service teachers. Although pre-service teachers are also postsecondary students, they were examined in their capacity as future teachers (e.g., attitudes toward students, perceptions of student ability). Thus, these studies are presented alongside investigations of currently practicing teachers in relation to weight bias. Research with teachers and pre-service teachers examined attitudes and behaviors toward students with obesity generally as well as specific to perceptions of academic ability. A few studies tested interventions aimed at reducing weight bias of current and future teachers.

Teacher Attitudes

Twelve studies investigated teacher attitudes toward students with obesity, their perceptions of student ability, or their attitudes toward weight-related bullying policies [14, 41,42,43, 44•, 45, 46,47,48, 49•, 50, 51]. Results from these studies indicated the presence of explicit and implicit weight bias among non-specialist as well as PE teachers [41, 46], as well as the belief that children with obesity are a burden and have control over their body weight [51]. Martinez-Lopez et al. [47] found that teachers having higher perceived self-efficacy in fostering participation among students with overweight/obesity also had more positive attitudes toward these students. Despite evidence of weight bias among teachers, Puhl et al. [49] found that teachers recognized weight-based bullying as an issue and supported bullying-related prevention and intervention policies.

Researchers examining the influence of obesity on teacher’s perceptions of academic ability found that teachers rated children with normal weight as having above-average abilities [50] whereas students with obesity were more likely to be perceived as having academic challenges [45]. Researchers also found that girls with obesity were perceived as having lower reading ability while boys with obesity were perceived as having lower math ability [44•]. Researchers also found that PE teachers had lower physical expectations for students with overweight/obesity [43] and perceived them to have poorer physical abilities [48]. Finally, researchers have looked at the influence of weight bias in a postsecondary setting. In an experimental investigation of the impact of body weight on graduate school admission decisions by faculty members, researchers found that having a high BMI was associated with fewer offers of admission, especially among female applicants [14]. In another study, PE faculty members indicated a willingness to have students with obesity within their program, but did not believe that a physical educator with obesity would be a positive role model for students [42].

Teacher Behavior

Two studies investigated classroom behavior or behavioral intentions toward students with obesity [52, 53]. After engaging in field observations and interviews with PE teachers, researchers observed that students with overweight were regarded as different, were provided with individualized goals, and were perceived as a challenge to teachers [52]. In an experimental investigation, it was found that PE teachers were more likely to intervene in an instance of bullying for a female student with overweight compared to a female student without overweight, and that there were no differences in likelihood of intervention for male students [53].

Pre-Service Teacher Attitudes

Eight studies investigated attitudes of pre-service teachers toward child or adolescent students with obesity [56,57,58,59,60,61,62,63]. Studies with both a general sample of pre-service teachers [56, 62] and samples of PE pre-service teachers [49•, 63] have reported implicit and explicit weight bias in these samples. In qualitative research, PE pre-service teachers described the belief that weight is a proxy for health, that body weight is within individual control, and indicated a desire to assist students with obesity with weight loss [63]. When comparing the attitudes of PE pre-service teachers with non-specialist pre-service teachers or non-education postsecondary students, researchers have found that weight bias exists among all samples, but that pre-service teachers with a PE specialty display higher weight bias compared to non-PE teachers [57] or non-education postsecondary students [60] as well as significantly lower expectations for students with obesity [58]. Muller et al. [59] conducted an experimental investigation of the impact of information related to weight on the judgments of 57 pre-service teachers about students’ academic and social skills. Contrary to previous research, the results of this study suggested that pre-service teachers perceived children and youth with overweight as having better academic skills than non-overweight students and similar social skills as non-overweight students [59].

Intervention Research

Five studies reported on the results of weight bias reduction interventions, three with pre-service teachers [64,65,66], one with a mixed sample of pre-service and in-service teachers [54], and one with a sample of teachers and health professionals [55]. After receiving a 3-h intervention, pre-service teachers specializing in PE reported an increased awareness of weight bias, but were concerned with how to incorporate information about body image into their instruction [66]. After a similar 3-h intervention, elementary specialist pre-service teachers reported a significant decrease in both implicit and explicit weight bias as well as a significant increase in perceived self-efficacy in addressing weight-related content in their instruction [64]. In another sample of pre-service teachers, Tingstrom and Nagel [65] conducted a 1-h intervention that included information about environmental influences on weight, weight bias, and positive teaching strategies, which corresponded to a significant decrease in explicit weight bias. Following an online module promoting body size acceptance, pre-service students and teachers both reported a decrease in explicit weight bias [54]. Finally, among a sample of teachers and health professionals, participants taking part in an intervention promoting a view of health as occurring at any body size improved their awareness of weight bias and improved self-efficacy to address weight bias in schools [55].

Discussion

Weight bias in educational settings has the potential to significantly impact individuals’ well-being and educational experiences. The studies reviewed herein reinforce the existence of weight bias within educational settings among children, adolescents, and teachers as well as among future teachers. Specifically, our review showed that students in K-12 schools frequently experience weight bias in multiple forms from peers in all spaces within schools. In samples of teachers and pre-service teachers, our review showed that negative attitudes toward students with obesity are pervasive and negatively impact perceptions of student ability. While emerging, intervention research has provided positive results among samples of K-12 students, teachers, and pre-service teachers.

Future Research Directions

The results of this review highlight a need for researchers to place greater emphasis on expanding weight bias research in several underexamined areas. Weight bias with pre-service and in-service teacher populations is well established as well as within the K-12 student population. However, more evidence that weight bias is carried from the K-12 settings into the educational experiences of postsecondary students is needed. More knowledge on the factors that impact weight bias in teachers in general, as well as PE teachers specifically, is necessary to better understand the nature of weight bias in these populations [51]. A better understanding of weight bias among teachers will provide the opportunity for more effective weight bias reduction interventions to be developed for this population. Additionally, although the incidence of weight bias among students is well established, more research is needed to understand potential contributing factors to weight bias in educational settings (e.g., BMI screenings [67]) and obesity prevention programs in schools [68].

Our review indicated a lack of research examining weight bias reduction interventions with students, teachers, and pre-service teachers, with existing research limited to small sample sizes. Addressing weight bias in K-12 and postsecondary educational settings brings with it unique challenges, such as creating developmentally appropriate interventions that can be implemented to meet multiple needs (i.e., curricula) within the limitations of existing policies and practices (i.e., school bullying legislation). In addition, interventions may be most effective when they are tailored to the institution in which they are implemented, meaning additional research needs to investigate how efforts might be individualized to meet the needs of a variety of different settings. Finally, interventions are most likely to be successful if they enlist the support of various stakeholders (i.e., adolescents who live with obesity) by employing a community-based, student-oriented research approach [69].

Finally, our review highlighted methodological limitations of research in this area. The majority of research conducted to date has been with cross-sectional samples with descriptive, correlational, or qualitative data. While these studies have provided valuable information regarding the impact of weight bias on the educational experiences of students, an increase in experimental and/or longitudinal research will help investigate educational disparities experienced by students with obesity. Further, most studies have primarily white participants and research with more diverse samples is needed to develop a better understanding of how weight bias impacts the educational experiences of students from various racial, ethnic, and other diverse backgrounds.

Limitations

Although this review highlighted the impact of weight bias in educational settings, not all aspects of weight bias or weight-related issues were captured. For example, this review did not examine differences in academic achievement based on body weight, which has been examined in a previous review [20]. Future research should examine if negative attitudes toward students with obesity influence educational attainment and contribute to inequity over time in educational settings. This review also did not examine variables that could be related to weight bias such as the impact of thin-ideal internalization, disordered eating practices, and other weight-related attitudes, which have been shown to negatively impact the educational experiences of students of all sizes [70].

Conclusion

It is important to gain a greater understanding of the occurrence and impacts of weight bias in educational settings in the short and long term, and the factors that contribute to and sustain weight bias among students and teachers, as well as interventions to reduce or prevent it. Further research in this area will continue to establish weight bias as a social justice issue to be addressed within educational settings [71]. Reducing weight bias is critical to creating educational environments wherein students and teachers of all sizes are embraced and experience equitable treatment necessary for success.