Effects of a Web-based Food Portion Training Program on Food Portion Estimation

ObjectiveAssess the effects of a prototype computerized food portion tutorial (CFPT).DesignParticipants were randomly assigned to estimate portion sizes for selected food items either prior to or following CFPT training (between groups), and those estimating before CFPT training re-estimated portions after training (within groups).SettingResearch offices.ParticipantsSeventy-six adult participants without dietary restrictions.InterventionThe CFPT is a Web-based food portion training program that displays varied portions of 23 food items with user-controllable reference objects and viewing angles.Main Outcome MeasuresEstimated vs. weighed portions of food items selected for a meal.AnalysisNonparametric tests were performed on estimated vs. weighed portion differences and on accuracy ratios between and within groups.ResultsA significant difference was found between conditions, both within and between groups, on the discrepancy between estimated and weighed portions for a number of the food items. Training exposure, however, resulted primarily in a shift from underestimation to overestimation, not more accurate estimation.Implications for Research and PracticeThe CFPT produced a significant impact on food portion estimation but appeared to sensitize participants to underestimation errors, leading to overestimation errors. Computerization of food portion training programs holds promise for providing cost-efficient portion estimation training but requires further development and evaluation before being considered for clinical use.