A post hoc comparison between inpatients with obesity and healthy-weight subjects in the size estimation accuracy of shoulders, waist, and hips widths and circumferences

Purpose: This post hoc study aimed to assess the hypothesis that subjects with obesity could underestimate their body size. Methods: Data from a previous study with different aims were used to compare 22 female inpatients with obesity with 21 healthy-weight women in the size estimation accuracy of their shoulders, waist, and hips circumferences and widths. The body estimation task with an individualized metric methodology was used to collect data. Frequentist and Bayesian analyses were performed. Results: Samples differed significantly in the accuracy measures of shoulders width and hips as well as waist circumferences: inpatients with obesity underestimated them, while healthy-weight subjects estimated shoulders width accurately but overestimated their hips and waist circumferences. Multiple regression showed that the between-group difference in the accuracy measure of shoulders width was explained by the individuals’ education level, while the difference in the accuracy measure of waist circumference resulted to be independent of both age and education level. Conclusion: This post hoc study supports the hypothesis that female patients with obesity might underestimate their body size. If these results will be confirmed in future studies, interventions specifically designed to equalize estimations to match the real measures of body size may play a key role in weight-reduction programs for people with obesity. Level of evidence: Level III, evidence obtained from cohort or case–control analytic studies.