Accepted for/Published in: JMIR Human Factors
Date Submitted: May 31, 2024
Date Accepted: Dec 22, 2024
Description and Usability Evaluation of NutriDiary, a Smartphone-based Dietary Record App
ABSTRACT
Background:
Repeated applications of short-term dietary assessment instruments are recommended for estimating usual dietary intake. For this purpose, NutriDiary was developed, a smartphone app for collecting weighed dietary records (WDR) in the German population. Users can search for foods by free text entry or barcode scanning.
Objective:
To test the usability and acceptability of NutriDiary, an evaluation study was conducted.
Methods:
The study sample comprised 74 participants (69% female) aged 18 to 64 years of whom 36% were experts (nutritionists). Participants completed a one day WDR and entered a pre-defined dummy meal (n=17 foods) the following day by using NutriDiary. An evaluation questionnaire was answered from which the System Usability Scale (SUS) Score (0–100) was calculated. A backward selection procedure (PROC REG in SAS®) was used to identify potential predictors for the SUS score (age, sex, status (expert/laymen), operating system (iOS/Android)).
Results:
The median SUS score of 75 (Q25-Q75: 62.5-87.5) indicated good usability. Age was the only characteristic identified as a potential predictor for a lower SUS score (P< .001). The median completion time was 35 min (Q25-Q75: 19-52) for completing an individual WDR and 15 min (Q25-Q75: 12-18) for the dummy meal. Older participants took longer to enter the data than younger ones (18-30 years: 1.5 min/item (1.1-2.0) vs. 45-64 years: 1.8 min/item (Q25-Q75: 1.3-2.3)). The majority of participants expressed a preference for NutriDiary over the traditional paper-based method.
Conclusions:
Good usability and acceptability in experts and laymen make NutriDiary promising for use in nutritional studies.
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