Image-Based Dietary Assessment Ability of Dietetics Students and Interns.

Erica Howes,Emily J Tomayko,Deborah A Kerr,Mary Cluskey,Carol J Boushey

doi:10.3390/nu9020114

Abstract

Image-based dietary assessment (IBDA) may improve the accuracy of dietary assessments, but no formalized training currently exists for skills relating to IBDA. This study investigated nutrition and dietetics students’ and interns’ IBDA abilities, the training and experience factors that may contribute to food identification and quantification accuracy, and the perceived challenges to performing IBDA. An online survey containing images of known foods and serving sizes representing common American foods was used to assess the ability to identify foods and serving sizes. Nutrition and dietetics students and interns from the United States and Australia (n = 114) accurately identified foods 79.5% of the time. Quantification accuracy was lower, with only 38% of estimates within ±10% of the actual weight. Foods of amorphous shape or higher energy density had the highest percent error. Students expressed general difficulty with perceiving serving sizes, making IBDA food quantification more difficult. Experience cooking at home from a recipe, frequent measuring of portions, and having a food preparation or cooking laboratory class were associated with enhanced accuracy in IBDA. Future training of dietetics students should incorporate more food-based serving size training to improve quantification accuracy while performing IBDA, while advances in IBDA technology are also needed.

Highlights

Current dietary assessment methods, including dietary records, 24-h dietary recalls, and food frequency questionnaires, are subject to errors that can influence overall accuracy of the assessment.Validation studies using doubly-labeled water have revealed high rates of underreporting using traditional diet assessment methods, especially in certain subpopulations [1,2]
The objectives of this study were (1) to assess the ability of nutrition and dietetics students and interns to perform Image-based dietary assessment (IBDA); (2) to explore factors relating to dietetics training and experience that may contribute to enhanced accuracy in IBDA; and (3) to identify challenges to performing IBDA
38% of the estimates were within ±10% of the ground truth, which is higher than the results found by Japur and Diez-Garcia [20] using foods estimated in person, who found that only 18.5% of serving size estimates by nutrition students were within ±10% of the ground truth

Summary

Introduction

Current dietary assessment methods, including dietary records, 24-h dietary recalls, and food frequency questionnaires, are subject to errors that can influence overall accuracy of the assessment. Validation studies using doubly-labeled water have revealed high rates of underreporting using traditional diet assessment methods, especially in certain subpopulations [1,2]. One method of preventing errors in reporting is training participants on serving size estimation skills. Several studies have reported improved accuracy after training individuals; in comparison to doubly-labeled water, accuracy remains low [4,5,6,7,8]. Image-based dietary assessment methods have emerged as potential tools for increasing the accuracy of reported diet intake [9,10]. The use of images allows for visual representations of the client’s diet to be captured, removing some of the reliance on memory and providing a more objective measure of a client’s diet [12]

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Discussion

Conclusion