Background Over the last decade, health mobile apps have become an increasingly popular tool used by clinicians and researchers to track food consumption and exercise. However, many consumer apps lack the technological features for facilitating the capture of critical food timing details. Objective This study aimed to introduce users to 11 apps from US app stores that recorded both dietary intake and food timing to establish which one would be the most appropriate for clinical research. Methods To determine a viable app that recorded both dietary intake and food timing for use in a food timing–related clinical study, we evaluated the time stamp data, usability, privacy policies, the accuracy of nutrient estimates, and general features of 11 mobile apps for dietary assessment that were available on US app stores. The following apps were selected using a keyword search of related terms and reviewed: text entry apps—Cronometer, DiaryNutrition, DietDiary, FoodDiary, Macros, and MyPlate; image entry apps—FoodView and MealLogger; and text plus image entry apps—Bitesnap, myCircadianClock, and MyFitnessPal. Results Our primary goal was to identify apps that recorded food time stamps, which 8 (73%) of the 11 reviewed apps did. Of the 11 apps, only 4 (36%) allowed users to edit the time stamps. Next, we sought to evaluate the usability of the apps using the System Usability Scale across 2 days, and 82% (9/11) of the apps received favorable scores for usability. To enable use in research and clinical settings, the privacy policies of each app were systematically reviewed using common criteria, with 1 (9%) Health Insurance Portability and Accountability Act–compliant app (Cronometer). Furthermore, protected health information was collected by 9 (82%) of the 11 apps. Finally, to assess the accuracy of the nutrient estimates generated by these apps, we selected 4 sample food items and a 3-day dietary record to input into each app. The caloric and macronutrient estimates of the apps were compared with the nutrient estimates provided by a registered dietitian using the Nutrition Data System for Research database. In terms of the 3-day food record, the apps were found to consistently underestimate daily calories and macronutrients compared with the Nutrition Data System for Research output. Conclusions Overall, we found that the Bitesnap app provided flexible dietary and food timing functionality capable of being used in research and clinical settings, whereas most other apps lacked in the necessary food timing functionality or user privacy.

UNSTRUCTURED Abstract: Over the last decade, health apps have become an increasingly popular tool utilized by clinicians and researchers to track food consumption and exercise. However, as consumer apps have primarily focused on tracking dietary intake and exercise, many lack technological features to facilitate the capture of critical food timing details. To determine a viable app that recorded both dietary intake and food timing for use in our clinical study, we evaluated the timestamp data, usability, privacy policies, accuracy of nutrient estimates, and general features of 11 mobile apps for dietary assessment. Apps were selected using a keyword search of related terms and the following apps were reviewed: Bitesnap, Cronometer, DiaryNutrition, DietDiary, FoodDiary, FoodView, Macros, MealLogger, myCircadianClock, MyFitnessPal, and MyPlate. Our primary goal was identifying apps that record food timestamps, which 8 of the reviewed apps did (73%). Of those, only 4/11 (36%) allowed users to edit the timestamps, an important feature. Next, we sought to evaluate the usability of the apps, using the System Usability Scale (SUS) across 2 days, with 82% of the apps receiving favorable scores for usability (9/11 apps). To enable use in research and clinic settings, the privacy policies of each app were systematically reviewed using common criteria with 1 Health Insurance Portability and Accountability Act (HIPAA) compliant app (Cronometer). Furthermore, protected health information is collected by 9/11 (81%) of the apps. Lastly, to assess the accuracy of nutrient estimates generated by these apps, we selected 4 sample food items and one researcher’s 3-day dietary record to input into each app. The caloric and macronutrient estimates of the apps were compared to nutrient estimates provided by a registered dietitian using the Nutrition Data System for Research (NDSR). Compared to the 3-day food record, the apps were found to consistently underestimate calories and macronutrients compared to NDSR. Overall, we find the Bitesnap app to provide flexible dietary and food timing functionality capable for research or clinical use with the majority of apps lacking in necessary food timing functionality or user privacy.