Dietary pattern and diversity analysis using 'DietR' package in R

There are scarce resources available for analyzing 24-hour dietary records. Here we introduce DietR, a set of functions written in R for the analysis of 24-hour dietary recall or records data, collected with either the Automated Self-Administered 24-hour (ASA24) dietary assessment tool or two-day data from the National Health and Nutrition Examination Survey (NHANES). The R functions are intended for food and nutrition researchers who are not computational experts. DietR provides users with functions to (1) clean dietary data; (2) analyze 24-hour dietary intakes in relation to other study-specific metadata variables; (3) visualize percentages of calorie intake from macronutrients; (4) perform principal component analysis (PCA) or k-means to group participants by similar dietary patterns; (5) generate foodtrees based on the hierarchical information of food items consumed; (6) perform principal coordinate analysis (PCoA) taking food classification information into account; (7) and calculate diversity metrics for overall diet and specific food groups. DietR includes a set of tutorials available on a website (https://computational-nutrition-lab.github.io/DietR/), which are designed to be self-paced study materials. DietR enables users to visualize dietary data and conduct data-driven dietary pattern analyses using R to answer research questions regarding diet. As a demonstration of DietR, we applied DietR to a set of created 24-hour dietary records data to demonstrate the basic functions of the package. We also applied DietR to a subset of 24-hour recall data from NHANES to demonstrate analyses using dietary diversity metrics. We present the results of this example NHANES analysis comparing legume diversity with waist circumference.