An exploratory study on portion size estimation errors: psychological correlates of portion size estimation errors in a non-clinical sample with normal-weight

PURPOSE: Accurate perception of food portion sizes is implicated in healthy eating, yet little is known about psychological correlates of portion estimation in non-clinical, normal-weight adults. This exploratory study examined whether consumption intent (self vs other) and markers of psychological processes associated with eating (dietary restraint, shape/weight overvaluation, body dissatisfaction) are associated with portion size estimation errors, and whether these errors relate to body mass index (BMI). METHODS: ) without current or past psychiatric disorders were included. Eating psychopathology was assessed using the brief 7-item, 3-factor version of the Eating Disorder Examination Questionnaire (Dietary Restraint, Shape/Weight Overvaluation, Body Dissatisfaction). Portion estimation was measured with the Portion Estimation Task, with images rated on a visual analog scale (0-100) under two conditions: general intent (for others) and intent-to-eat (for self). A proportional estimation error index was calculated across all non-full portion sizes relative to each participant's full-portion reference. A linear mixed model tested the effect of intent and Pearson correlations examined the association with psychological variables and BMI. RESULTS: = 0.27, p = 0.021), but not with Shape/Weight Overvaluation or Body Dissatisfaction. BMI correlated with Shape/Weight Overvaluation and Body Dissatisfaction, but not with Dietary Restraint or the Estimation Error Index. CONCLUSION: In normal-weight adults without eating disorders, greater dietary restraint is associated with larger biases in portion size estimation, whereas BMI and body-related evaluative concerns primarily track weight status rather than perceptual errors in portion size estimations. Findings are exploratory and warrant replication in larger, more diverse samples. LEVEL OF EVIDENCE: III. Evidence obtained from well-designed cohort or case-control analytic studies.