Faculty Bibliography

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.

OBJECTIVE: Study objectives were to assess the accuracy of a food record delivered on a personal digital assistant (PDA) and to examine sources of error from the PDA-based food record. METHODS: Thirty-nine adults recruited with a newspaper advertisement were trained to record food intake using DietMatePro, a dietary assessment program delivered on a PDA. After 3 d of use, subjects returned for a follow-up visit in which a 24-h recall was conducted. Subjects also were timed while recording an observed, weighed lunch. Recalled and actual food intakes were compared with estimates recorded by the subjects when using the PDA. Paired sample t tests and Pearson's correlations assessed means and measurements of association between DietMatePro data compared with the 24-h recall data and observed meal data. Bland-Altman plots were used to assess bias in food recording. Sources of error were quantified by using calories as the unit for comparison. RESULTS: There were no significant differences in daily totals for calories and macronutrients between DietMatePro data and comparison measurements. Pearson's correlations of associations between DietMatePro data and the comparison measurement ranged from 0.505 to 0.797 (P < 0.005, n = 28) for the 24-h recall and from 0.419 to 0.786 (P < 0.005, n = 33) for the observed lunch, depending on the nutrient measured. The largest source of absolute error in caloric estimation was attributable to portion size estimation error (49%). CONCLUSIONS: DietMatePro, a PDA-based dietary assessment program, provides a method of assessing energy and macronutrient intakes comparable to the 24-h recall in samples lacking dietary restrictions.