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

Abstract

Objective Assess the effects of a prototype computerized food portion tutorial (CFPT). Design Participants 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). Setting Research offices. Participants Seventy-six adult participants without dietary restrictions. Intervention The 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 Measures Estimated vs. weighed portions of food items selected for a meal. Analysis Nonparametric tests were performed on estimated vs. weighed portion differences and on accuracy ratios between and within groups. Results A 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 Practice The 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.