A Survey of Personal Visualization in mHealth Nutrition Apps Corrie M. Whisner, Alexandra Porter, Nicholas Pecor, and Ross Maciejewski Senior Member, IEEE ABSTRACT One emerging means of engaging and educating individuals and communities is the combination of mobile computing, medical sen- sors, and communication technology (commonly referred to as mo- bile health or mHealth) that can enable the tracking and personal visualization of the physical health of the user. To date, hundreds of mobile apps are available for smartphone users for tracking nutri- tion and weight related elements of personal health. Unfortunately, few apps report on the use of evidence-based practices [4] or be- havioral theory [12] in their development and/or programming and fewer still provide users with means of quickly analyzing their per- sonal longitudinal data, relying primarily on static charts of the pie, bar or line variety. In this paper, we survey a small set of mHealth applications for diet and nutrition and identify app functions that would relate to traditional methods of assessing dietary intake and physical activity as well as advice-giving for meal planning and improvement. We discuss the use of personal visualization in this context and close with speculation on novel ways in which the com- munity could explore visualization design for influencing personal changes. 1 I NTRODUCTION Obesity has reached epidemic proportions globally with over 1 out of every 3 adults being classified as obese. Overweight and obesity are linked to increased risks in chronic diseases including heart dis- ease, diabetes, osteoporosis and some cancers. Such chronic dis- eases are a major contributor to the rising health care costs faced in the United States, accounting for approximately $147 billion of medical costs in 2008 [6]. In order to combat this growing problem, new methods of communicating and educating people about health issues related to overweight and obesity are needed. The Office of the Surgeon General [1] has emphasized the need for engaging and educating communities about healthy eating habits based on the Dietary Guidelines for Americans. In fact, the nutrition and weight status objectives for Healthy People 2020 focus specifically on the promotion of healthful diets and regular physical activity as a means of improving individual health over time [2]. According to the 2015 Pew Research Center Internet and Amer- ican Life Project, data suggest that a total of 62% of smartphone owners used their phones to explore health information in 2014. In 2012, exercise, diet and weight apps were among the most popu- lar health apps with 38%, 31% and 12% of users utilizing apps to track exercise, dietary intake and body weight, respectively. De- spite the increased usage of these tools there are few data to sug- gest that these apps are effective for achieving health-related goals, as many of the most popular apps do not report the use of evidence- based practices in their development and/or programming [4]. Fur- thermore, few apps take advantage of visualization. The research agenda on personal visualization by Huang et al. [9] defines sev- eral critical areas that would need to be addressed to improve the efficacy of mHealth nutrition apps, specifically the notions of en- abling relevant context for reasoning with the data (i.e., what was I doing/feeling when I engaged in unhealthy eating habits?), defining appropriate baselines (i.e., how do I compare to others, normative data or population standards in the nutrition literature), and shar- ing/privacy issues (i.e., some research suggests that sharing health data within a community may improve self-management [7]). 2 A BRIEF SURVEY OF MHEALTH NUTRITION APPS In this paper, we present a survey of the most highly downloaded Android and Apple App Store nutrition apps from the winter of 2014. Each app was reviewed looking for functionality that enabled calorie, nutrient, fitness and weight tracking as well as goal setting, peer comparison, social network sharing, meal planning advice and incentives/gamification. Tables 1 and 2 show 15 of the most popular apps (based on number of downloads and ratings) along with a sum- mary of the most common positive and negative comments about each app. Representative comments for the apps were extracted from the app stores to explore sentiment and topics relating to user preferences and software functionality. The sample apps shown here were collected using keywords: “nutrition, diet, health”. Func- tionality of the apps was then broken into nine different categories that are representative of methods/approaches commonly utilized in clinical settings (calorie, nutrient, fitness and weight tracking as well as goal tracking, peer comparison, social networking/sharing, meal suggestions and gamification/incentives). Screen shots were also captured to show representative visualizations (or lack thereof) from the apps. Of the 15 apps reviewed, the majority (n=14) were multi- functional providing functions beyond nutrient, fitness and weight tracking alone. The most common features among these apps were goal-setting (n=14; primarily weight-related goals), weight (n=15), physical activity (n=11) and calorie (n=12) tracking. Although peer support has been shown to positively impact health, only nine of the apps included a social networking feature and only 4 apps provided peer support functionality. The least common features were meal planning/recipes (n=1) and incentives/gamification (n=3). Visualizations provided in the apps under review included line graphs, pie charts and bar graphs. Nutrition displays/images were limited to visualizing macronutrients (protein, carbohydrate and fat) in pie charts to illustrate the breakdown of these core nutri- ents. Vitamins and minerals (micronutrients) were frequently visu- alized using bar-type graphs. Apps such as MyFitnessPal allow for personalization of dietary and physical activity goals but lack edu- cational components to assist the user in making evidence-based goals. Other dietary trackers, including FatSecret, MyFitness- Pal, Lose It!, LIVESTRONG Calorie Tracker, MedHelp’s Calorie Counter, and SparkPeople’s Calorie Counter all offer the ability to track specific food items on a daily basis. However, the only vi- sualization options in any of these are pie graphs based on macro- nutrients (protein, fat, and carbohydrates) and bar charts of calories, sugar, or other nutrients. Detailed data are presented almost exclu- sively through text and tables, and effective tracking requires the input of all food items consumed. While this process is simplified on these applications by making suggestions based on past records and allowing for bar code scanning, there is no way to enter general information about a user’s diet that can be used to assess their nu- tritional behaviors. Furthermore, few of these apps allow visualiza- tion or interaction with behavior goals and the allowable changes to behavior goals may not be broad enough to meet the needs of users with additional complications beyond weight, such as cardiovascu- lar disease, diabetes, Celiac disease, food allergies, etc. As such, we feel that an interesting avenue for personal visualization and