Accepted for/Published in: JMIR Formative Research
Date Submitted: Mar 28, 2022
Date Accepted: May 26, 2022
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Assessing validity of the PortionSize app to estimate dietary intake among adults: A pilot study
ABSTRACT
Background:
Accurately assessing dietary intake can promote improved nutrition. The PortionSize© app is designed to quantify and provide real-time feedback on intake of energy, food groups, saturated fat, and added sugar.
Objective:
This study assessed the preliminary validity of estimating food intake using the PortionSize app among adults.
Methods:
Fifteen adults (18-65 years) were recruited and trained to quantify food intake from a simulated meal using PortionSize. Trained personnel prepared 15 simulated meals and covertly weighed (weigh back [WB]) the amount of food provided to participants, as well as food waste. Equivalence tests (+/- 25% bounds) were performed to compare PortionSize to WB.
Results:
Participants were 28 ± 12 years (Mean ± SD) and 73.3% female. Mean energy intake (EI) estimated with PortionSize was 742.9 ± 328.2 kcal and WB was 659.3 ± 190.7 kcal (mean EI difference, 83.5 ± 287.5 kcal). The methods were not equivalent in estimating EI (P = .18), and PortionSize overestimated EI by 83.5 kcal (12.7%) at the meal level. Estimates of portion size (gram weight), total sugar, fruit, and dairy servings with PortionSize were equivalent to WB (all P values < .05). PortionSize was not equivalent to WB for carbohydrate, fat, vegetables, grain, and protein servings (all P values > .05).
Conclusions:
Due to power limitations, the equivalence tests had large equivalence bounds. Though preliminary, the results of this small pilot study warrant further development and validation of PortionSize as means to estimate EI and provide users with real time and actionable feedback. Clinical Trial: Registered at ClinicalTrails.gov (NCT04494971); https://clinicaltrials.gov/ct2/show/NCT04494971
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