We examined associations between IWB and impairment in HRQoL in a treatment-seeking sample of overweight and obese men and women. The main findings were twofold. First, IWB was associated with greater perceived impairment in both the physical and mental health domains of HRQoL. Second, IWB contributed significantly and independently to the variance in physical and mental health impairment over and above the contributions of BMI, age, exercise, medical conditions, and medication use. The association between IWB and health impairment among overweight and obese individuals is consistent with past studies demonstrating that prejudice and internalized bias may be linked to adverse health outcomes in other commonly stigmatized groups, such as gays, lesbians, bisexuals, and ethnic minorities [18, 30, 31]. For example, internalized racism has been associated with negative health outcomes among African Americans [32, 33]. It has been proposed that the stress associated with IWB may have a significant impact on cardiovascular health and metabolic abnormalities, which could potentially lead to poorer health, weight gain, and increased risk of internalized stigma . Stress associated with internalized bias may also lead to unhealthy coping behaviors, such as smoking, alcohol or substance use  or binge eating . Another potential coping behavior that could lead to poor HRQoL is avoidance. Phobic anxiety and avoidance of specific situations may result among obese individuals who have experienced weight stigma .
Although the cross-sectional design of the current study precludes any conclusions concerning the direction of the observed associations, it is worth considering the possibility that weight bias and its internalization may be conducive to adverse health outcomes among overweight and obese individuals, that is, in addition to the more commonly accepted view that impairment in HRQoL is a consequence of obesity. The present findings suggest that future research using prospective study designs should continue to address this issue.
The finding that, in this clinical sample of overweight and obese individuals, IWB was associated with significant impairment in both physical and mental health domains of HRQoL, independent of its association with medical comorbidity, suggests that it may be important to include the reduction of IWB as a key therapeutic goal of obesity treatment programs. There is some evidence that this goal is viable. For example, a day-long intervention directed at alleviating internalized bias by teaching acceptance and mindfulness significantly reduced IWB in obese participants in one recent trial . Future research of this kind should include assessment of the potential benefits of reducing IWB on specific aspects of HRQoL. Whether weight bias can be reduced at the population level is less clear . Therefore, from a public health perspective, it may be especially important to test the efficacy of health promotion and early intervention programs that seek to preempt the adverse effects of IWB on obese individuals’ quality of life.
Other limitations of the present study - that is, other than the use of cross-sectional study design - should be noted. First, we relied on a single, brief measure of HRQoL that yields scores on subscales relating to only physical and mental health impairment. Although the SF-12 is widely used and has good psychometric properties, the use of a more comprehensive measure, such as the SF-36, would be desirable. It would also be desirable to include an obesity-specific measure of HRQoL in future research e.g., , particularly in research designed to evaluate the effects of clinical intervention on levels of IWB, since a measure of this kind may be more sensitive to change. It would be interesting to examine how strong the correlation might be between IWB and an obesity-specific measure of HRQoL. Second, and whereas the assessment of medical comorbidity is a strength of the present study, other variables likely to be associated with both body weight and HRQoL were not assessed. The role of body dissatisfaction and eating-disordered behavior may be particularly important in this regard [23, 39, 40]. Future studies should also examine the relative effects of depression alongside those of IWB. Considering the relationship between obesity, depression, and HRQoL , it is possible that depression may account for variance in HRQoL or may mediate the relationship between WBIS and HRQoL. In addition, it should be noted that the assessment of medical comorbidity and related variables was by self-report. Data bearing on actual (diagnosed) medical comorbidity and documented use of medication would, of course, be preferable. Finally, the current study included a large proportion of Asian participants and participants of mixed (primarily Asian, Pacific Islander, and Caucasian) descent. The use of this this study population may limit the generalizability of the findings, although the choice of study population might also be considered a strength of the study, given the reliance on Western populations in most previous research. In any case, further research exploring the associations of IWB with impairment in quality of life, in different study populations, would be welcome.