Evaluation of Mobile Applications as an Alternative to Weighed Food Records and Food Frequency Questionnaires for Dietary Assessment in Japan.

Introduction  Dietary surveys are essential in nutritional epidemiology. While the weighed food record method is highly accurate and commonly used in Japan, it is unsuitable for large-scale studies due to its labor-intensive nature. Mobile applications for dietary assessment have gained popularity as alternatives, offering convenience and automation. This study aimed to evaluate the feasibility of using mobile applications as a substitute for traditional methods like weighed food records and food frequency questionnaires (FFQs) in population-based dietary assessments, specifically by examining the correlation between nutrient intake estimates obtained from a mobile application and those from traditional methods. Methods  This cross-sectional study was conducted from May 1 to June 30, 2022, and included 85 third-year female students (mean age: 20.2 ± 0.6 years; range: 20-25 years) from the Department of Nutrition, Faculty of Health Sciences, Kio University, Nara, Japan. All participants were Japanese nationals with a uniform educational background, were unmarried, and had received formal training in nutrition and dietary assessment as part of their curriculum. Dietary intake data were collected using both weighed food records and the Calomeal® mobile application (Life Log Technology, Inc., Tokyo, Japan), which enables users to record intake via food photos or manual entry and provides automatic analysis for 29 nutrients. Each participant recorded all foods and beverages consumed on a single weekday of their choice during the study period. There were no dropouts; all enrolled participants completed the study procedures. Nutrient intake estimates from the app and weighed food records were compared using Spearman's correlation coefficients. The proportion of participants not meeting the Estimated Average Requirement (EAR) was assessed using the cut-point method. All statistical analyses were performed using IBM SPSS Statistics for Windows, version 28 (IBM Corp., Armonk, New York, United States). Results  High correlations (0.7 ≤ |ρ| ≤ 1) were observed between nutrient intake estimates from the app and weighed food records for most nutrients, although moderate correlations (0.4 ≤ |ρ| < 0.7) were noted for specific nutrients like magnesium, iron, and vitamin B12 during certain meals. Comparisons with FFQs showed weaker correlations, consistent with previous findings. The mobile application demonstrated significant potential as a reliable tool for dietary assessment, particularly in large-scale studies where traditional methods pose logistical challenges.  Conclusions  Mobile applications like Calomeal® provide a viable alternative to weighed food records for dietary assessments, offering high accuracy and ease of use. They outperform FFQs in precision and reduce logistical challenges, making them suitable for large-scale nutritional studies.