Empirical evidence suggests that obese people are discriminated in different social environments such as the work place. Yet, the degree to which obese people are internalizing and adjusting their own behaviour as a result of this discriminatory behaviour has not been studied thoroughly. We develop a proxy for measuring experimentally the self-weight bias by giving to both self-identified obese (n=90) and non-obese (n=180) individuals the opportunity to request a positive amount of money after having performed an identical task. Consistent with the System Justification Theory, we find that self-identified obese individuals, due to a preexisting false consciousness, request significantly lower amounts of money than non-obese ones. A within subject comparison between self-reports and external interviewers' evaluations reveals that the excessive weight felt by the self but not reported by evaluators captures the self-weight bias not only for obese but also for non-obese individuals. Linking our experimental results to the supply side of the labour market, we argue that self-weight bias, as expressed by lower salary requests, enhances discriminatory behaviour against individuals who feel, but may not actually be, obese and consequently exacerbates the wage gab across weight.