Electronic Dietary Intake Assessment (e-DIA): relative validity of a mobile phone application to measure intake of food groups.

Automation of dietary assessment can reduce limitations of established methodologies, by alleviating participant and researcher burden. Designed as a research tool, the electronic Dietary Intake Assessment (e-DIA) is a food record in mobile phone application format. The present study aimed to examine the relative validity of the e-DIA with the 24-h recall method to estimate intake of food groups. A sample of eighty university students aged 19-24 years recorded 5 d of e-DIA and 3 d of recall within this 5-d period. The three matching days of dietary data were used for analysis. Food intake data were disaggregated and apportioned to one of eight food groups. Median intakes of food groups were similar between the methods, and strong correlations were found (mean: 0·79, range: 0·69-0·88). Cross-classification by tertiles produced a high level of exact agreement (mean: 71 %, range: 65-75 %), and weighted κ values were moderate to good (range: 0·54-0·71). Although mean differences (e-DIA-recall) were small (range: -13 to 23 g), limits of agreement (LOA) were relatively large (e.g. for vegetables, mean difference: -4 g, LOA: -159 to 151 g). The Bland-Altman plots showed robust agreement, with minimum bias. This analysis supports the use of e-DIA as an alternative to the repeated 24-h recall method for ranking individuals' food group intake.