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Mobile health (mHealth) has shown promise as a way to deliver weight loss interventions, including connecting users for social support.
To develop, refine, and pilot test the Social Pounds Off Digitally (POD) Android app for personalized health monitoring and interaction.
Adults who were overweight and obese with Android smartphones (BMI 25-49.9 kg/m2; N=9) were recruited for a 2-month weight loss pilot intervention and iterative usability testing of the Social POD app. The app prompted participants via notification to track daily weight, diet, and physical activity behaviors. Participants received the content of the behavioral weight loss intervention via podcast. In order to re-engage infrequent users (did not use the app within the previous 48 hours), the app prompted frequent users to select 1 of 3 messages to send to infrequent users targeting the behavioral theory constructs social support, self-efficacy, or negative outcome expectations. Body weight, dietary intake (2 24-hr recalls), and reported calories expended during physical activity were assessed at baseline and 2 months. All participants attended 1 of 2 focus groups to provide feedback on use of the app.
Participants lost a mean of 0.94 kg (SD 2.22,
The Social POD app provides an innovative way to re-engage infrequent users by encouraging frequent users to provide social support. Although more time is needed for development, this mHealth intervention can be disseminated broadly for many years and to many individuals without the need for additional intensive in-person hours.
Rates of overweight and obese US adults remain high with 69% having a body mass index (BMI) greater than 25 kg/m2 [
The use of apps on mobile devices (eg, smartphones and tablets) has the potential to improve how individuals monitor health behaviors by serving as a convenient platform to connect users to one another via online social networks. Mobile health (mHealth) holds promise as an effective method of delivering behavioral interventions addressing diet and physical activity, and it is less time-intensive than in-person, individual, or group sessions [
Weight loss programs have been developed and delivered via Internet and other Web-based platforms as well as through social media (eg, Facebook [
The overarching objective of this line of research has been to design an app that can be used to monitor and test scientific hypotheses related to optimal matching of participants to provide support for collective weight loss in the context of mobile interventions. The primary goal for this pilot study was to solicit participant feedback to refine the Social Pounds Off Digitally (Social POD) app for use in a larger pilot randomized clinical trial (RCT). The Social POD app was developed by a transdisciplinary team of researchers including experts in health behavior, nutrition, computer science, psychology, exercise science, and social work. The analysis sought to answer the following questions: (1) What features of the Social POD app needed to be refined or developed to further incentivize participants to use the app? (2) Were there any significant changes from pre- to poststudy in participant weight, calories consumed, and reported intentional physical activity? (3) Was participant weight loss correlated with frequency of app use over the course of the study?
Men and women who were overweight or obese with Android smartphones (BMI 25-49.9 kg/m2; N=9) were recruited in South Carolina for a 2-month weight loss pilot intervention to test usability and provide feedback to be used in the refinement of the smartphone app. Participants were recruited via worksite listserv announcements, flyers, and newspaper advertisements. Exclusion criteria included not having an Android phone, previous stroke or heart attack diagnosis, diagnosis of diabetes and using insulin or oral medications to control diabetes, BMI outside the range of 25.0-49.9 kg/m2, unable to attend required meetings, unable to access the Internet using a computer for completing assessments, having a psychiatric illness, receiving treatment for drug or alcohol dependency, having an eating disorder, participating in another weight loss program, being pregnant or planning on becoming pregnant during the study, and breastfeeding. Participants were excluded for endorsing any of the first 4 items on the revised Physical Activity Readiness Questionnaire (PAR-Q) [
Participants attended 4 in-person meetings: an orientation session to learn about the study and complete baseline dietary assessments; a training session to learn how to download and use the Social POD app and podcasts and to collect baseline height and weight measurements; a mid-study focus group at 1 month to provide feedback regarding the usability of the Social POD app, provide suggestions for improvement, and collect 1-month weight measurements; and an end-of-study session to provide 2-month weight measurements. All participants provided written consent. This study was approved by the University of South Carolina institutional review board.
Participants were instructed to track their total calories from all meals, snacks, and beverages consumed; minutes of intentional physical activity; and body weight each day for the duration of the 2-month usability study. Participants were instructed to use MyFitnessPal or LoseIt, free commercial diet-tracking apps with extensive nutrient databases, to look up calorie information for food and beverages consumed. Participants were then asked to transfer total calories from each meal and snack consumed for the day to the Social POD app. Screenshots of the tracking features are shown in
Participants received within-app notifications at certain times throughout the day to remind them to self-monitor (promoting self-regulation) diet, minutes of physical activity, and total body weight each day. Participants could view a history of all dietary, activity, and weight information entered on the within-app history screen. Participants could view weight entered on a weight graph. Participants who were frequently using the Social POD app (users who entered information in the app in the past 48 hours) were prompted via notifications to send encouraging messages to other group members who had not entered data in the app over the previous 48 hours (infrequent users). Messages were sent from frequent users by clicking the notification to send a message to an infrequent user, selecting one of three options listed on the message selection screen, and clicking Send. Screenshots of the message log, message selection, and history screen of the Social POD app features are shown in
This study is novel in that it used theory-based messages designed by the researchers to help re-engage infrequent participants over the course of the 2-month intervention. The participants were matched to provide support to one another based on principles of recommender systems used by some websites and applications (eg, Amazon and Netflix) [
User-to-user message types by social cognitive theory construct targeted.
SCT construct targeted | Construct definition | Sample message |
Self-efficacy | One’s belief in the ability to perform specific tasks and overcome barriers. | “I found some light recipes on the Internet and they look pretty good. Nutrition info is listed, so they’re easy to track too.” |
Social support | Support from others, which can take many forms including information, suggestions, or advice. | “Haven’t seen you log anything in the app lately. We miss you!” |
Outcome expectations | Expected outcomes of behaviors. | “I’ve never really succeeded at a diet before, but I think tracking my calories, weight, and exercise has to help this time around!” |
Participants were provided with 3 20-minute, evidence-based weight loss podcasts each week. Podcasts were uploaded to the study website, and participants were sent a reminder that a new podcast was available every Monday, Wednesday, and Friday via email. Participants were instructed to listen to the 3 podcasts within the week but could listen at a time and place of their choosing. Podcasts were informed by SCT and provided participants with a range of weight loss topics. Podcast topics included nutrition and exercise information, an audio diary tracking the weight loss progress with challenges experienced by a male and female character, and a weight loss soap opera depicting the challenges of overcoming social barriers to weight loss, with a goal-setting activity related to weight loss at the end of each episode. Specific information regarding the development and testing of these podcasts in previous interventions can be found elsewhere [
Screenshots (left to right) of the home, meal tracking, and physical activity tracking screens on the Social POD app.
Screenshots (left to right) of the message log, message selection, and history screens on the Social POD app.
Participants completed online questionnaires assessing demographic characteristics. Height was measured at baseline assessment only using a Seca 213 (Hamburg, Germany) calibrated stadiometer. Weight was measured at baseline and 2 months using a Seca 869 calibrated digital scale accurate to 0.01 kg. Dietary measures were completed by participants using the National Cancer Institute’s Automated Self-Administered 24-Hour Dietary Recall (ASA24) [
Participants attended 1 of 2 focus group sessions at 1 month to provide feedback regarding their use of the intervention components (Social POD app and podcasts). The focus groups were conducted by a trained focus group facilitator, and questions were asked using a semistructured interview guide developed by the investigators that included prescripted and spontaneous probes designed to elicit information from participants regarding their experience with the Social POD app. Questions were designed to assess participant satisfaction and dissatisfaction with the weight loss podcasts; the Social POD app including the tracking, prompting, and messaging features; and the weight graph and history features for future revisions. Participants were also asked if they would like incentives for using the app, and if so, how they would like an incentive system to be structured. Information regarding aesthetics and appearance of the app was solicited as well.
Focus group sessions were taped using an audio recorder, and all participants were instructed to use their study identification number to protect confidentiality during the focus groups. A trained graduate research assistant was present at the focus group sessions to take field notes during the sessions. The focus group facilitator completed detailed memos following each midstudy focus group session to document salient themes from participant discussions. Recordings from the 1-month focus group were transcribed verbatim by the research assistant and were cross-referenced with recordings for accuracy.
During the study (weeks 1 through 7) participants completed brief weekly online surveys each Friday to report the number of podcasts listened to and the number of days they used the Social POD app that week. Participants also reported any problems experienced using the Social POD app during the past 7 days and any suggestions they had to improve the app. If participants reported problems or suggestions for the Social POD app, they were then asked to write a detailed explanation.
All qualitative data were collected and analyzed between February and August 2014 using NVivo for Mac Beta 2014 statistical software (QSR International) to extract a combination of a priori and emergent themes from the focus groups to guide the revision of the Social POD app. Open-ended responses from weekly surveys regarding problems experienced and suggestions for improvements to the Social POD app were coded as well. Stata version 13.1 (StataCorp) software was used to detect statistical significance for all quantitative data analysis. Paired samples
A total of 34 individuals inquired about the study, 15 individuals qualified to participate, and 9 completed baseline measures and received the intervention. Major reasons why participants did not qualify included not having an Android phone (9/19, 47%) and meeting medical exclusion criteria (3/19, 16%). Most participants (7/9, 78%) attended the 1-month focus group sessions (2 infrequent app users did not attend), and all participants completed the poststudy questionnaire and unannounced dietary recalls and had their body weight measured poststudy. The response rate for weekly surveys was 62% (39/63). Baseline demographics of the study sample are presented in
Baseline demographic characteristics.
Characteristics |
|
n=9 |
Age (years), mean (SD) |
|
39 (14.5) |
|
|
|
Female | 8 (89) | |
|
Male | 1 (11) |
|
|
|
|
Black | 3 (33) |
|
White | 6 (67) |
Weight (kg), mean (SD) |
|
91.5 (19.1) |
Body mass index, mean (SD) |
|
35.5 (7.1) |
|
|
|
|
Advanced | 3 (33) |
|
College | 5 (56) |
|
Some college | 1 (11) |
|
|
|
|
Divorced or separated | 1 (11) |
|
Married | 2 (22) |
|
Single | 4 (44) |
|
Other | 2 (22) |
Major themes that emerged during focus group discussions are reported below with illustrative quotes from participants. These themes included Social POD app functionality, improvements to the Social POD app and podcasts, additions to the Social POD app, incentive and goal system for the Social POD app, and satisfaction with the Social POD app and podcasts.
Functionality problems reported by participants included issues with the notification system that prompted participants to track their daily diet, weight, and minutes of physical activity. Reported functionality issues with the notification system mentioned during the focus groups as well as on the weekly surveys included 1 failure to receive notifications and 1 failure of notifications to connect with the correct screen within the Social POD app. The same participant reported 2 instances of spontaneous crashing of the Social POD app on the weekly surveys.
Themes relating to suggested improvements for the Social POD app were varied and included adding additional features and modifying existing features. Modifying the color scheme and integrating options for personalization were suggested. One participant suggested using colors that “get your attention more” by replacing the grey and dark blue used in the current version of the Social POD app with brighter colors. Another participant mentioned she would like to have had the opportunity to choose an avatar or icon for her home screen to customize the appearance of her app. Having the ability to track calories consumed on previous dates was another requested modification. Most participants (3 out of 4 participants in this group) reported that the notifications to track their diet, physical activity, and weight were helpful as reminders to track their healthy behaviors, although 1 participant said she found them to be annoying.
There were not many suggested improvements for the podcasts during the focus groups, but participants did note problems with sound quality and variation in the volume level. A participant in the focus groups mentioned that there was a difference in the volume level of the various segments of the podcasts, specifically with the soap opera portion. Participants recommended leveling the volume and improving the sound quality of the podcast episodes prior to future use. While all participants reported that they valued the information provided in the podcasts and felt satisfied with the various segments, some participants (n=3) reported they did not like the soap opera portion of the podcast episodes. A participant shared, “I don’t particularly like the soap opera,” and 2 members of the group agreed with this statement and said this story line was “geared toward young dating women” and “negative.” Another participant would have enjoyed the soap opera portion of the podcast more if all of the episodes could be listened to consecutively rather than having to wait until the next episode was available to download.
Suggested additions to the Social POD app included adding a database of common foods and beverages within the app (versus having to use another app to look up calorie information) and incorporating an incentive system. Increasing the amount of praise provided by the study staff for entering weight and achieving weight loss–related goals was a highly suggested addition to the app. All of the participants that attended the focus groups (n=7) expressed their desire to see how others were doing in the program and to send other participants encouragement for achieving weight loss goals. A participant mentioned it would be interesting to see if messages sent to other users actually motivated them to use the app more often.
I think it’d be interesting to hear somebody from the receiving end to see if that motivated them to do something.
All participants in the focus groups reported they would like an incentive system with rewards for using the tracking components of the Social POD app. Participants suggested that points should be redeemed for prizes.
I’m all about a token economy, so yes,...I think like a five year old, so yeah, that [prizes] really does motivate me.
Participants recommended earning points specifically for completing physical activity.
I haven’t been nearly as active as I would have liked to have been...having a point reward system for that would be an incentive for me to move more.
A participant mentioned that creating a competition among study participants or giving prizes for personal bests would be motivating.
I certainly like prizes [laughter]. It could also be fun to have a competition between the Social POD users so you could have the leader in points receive some prize or even personal bests, like if you have a 5-week program and your best week you could get some rewards.
Participants recommended the integration of preset or tailored goals to limit the possibility that some might set unrealistic goals for themselves and give up on the program.
First participant: Think of the other side if you decide for yourself some goals, and for some reason you cannot make them, how would you feel?
Second participant: Really terrible, but if it was somehow like...If the system could somehow help you set reasonable goals instead of like high in the sky things that I know I’m not going to do. People do tend to set lofty goals for themselves when really it should be small, measurable, incremental changes at first.
Themes relating to satisfaction with Social POD app components included the user-to-user messaging system. Some participants preferred the prewritten user-to-user messages because they seemed more professional than allowing participants to create their own user-to-user messages.
I think the prepopulated messages is [are] the best because it’s professional.
Overall, participants reported satisfaction with the messaging system. A participant reported that she would have been less likely to send messages to others if she had to write the messages herself.
I know that I would be less likely to send a message to someone if I had to write it myself...so having some [messages] to choose from where it takes just a second to do, I’m more likely to do that.
Overall, participants reported the Social POD app was simple and easy to use. Participants reported they liked the convenience and ability to use their smartphones to track their diet, which they found to be more inconspicuous than other methods (eg, using a calorie book).
Every now and then you feel like James Bond because if you are at the table an[d] you still have your cellphone with you an[d] you turn on the app and...nobody knows what you do...an[d] you just...key in everything an[d] done. I mean [at] the end of the day...I’ve done something for myself today.
Participants also mentioned that the app gave them the motivation they needed to change their diet and physical activity behaviors to lose weight.
It’s definitely been a useful exercise...my thing is process, not perfection...in my case I’m doing a lot more than I was doing before.
All participants in the focus groups volunteered that they valued the information provided in the podcasts.
I liked the information...it reinforces what I’m sure most of us already know.
Participants reported a variety of methods used to listen to the weekly podcasts. A participant created an icon on the phone to easily access the podcasts and even set reminders to listen to the podcasts throughout the week.
I’ve set up the podcasts as an icon on my phone. So then I just go to the website and can play it from there, and then I have an alarm set up for Monday, Wednesday, and Friday because otherwise I’ll forget to [listen] even with an email I’ll probably forget.
Another participant reported listening to the podcasts from a laptop.
It’s easy, I told you, I listen to this on my laptop, and once I get the email, I just click on the link on my media system in the laptop [and] just open up, and I can see everything there. I wish they could stay. I wished at the end of the study [the podcasts] would not go away.
Participants reported listening to the podcasts in a variety of settings. Some participants reported listening to the podcasts while in the car.
I like to listen to it in the car when I’m going to be in the car for twenty or thirty minutes.
I like to listen to them in the car or when I’m getting ready in the morning and that’s a good time to do it, so I appreciate that your assistant sends them early in the morning, so I have a good time, a whole day really to listen to it.
All focus group participants mentioned that they liked at least one of the various segments included in the podcast episodes.
I also really like the section where you listen to someone’s diary...that’s helpful.
Another participant liked the diversity of characters included in the podcasts.
I like there’s an array of people who share. Older gentlemen, the women, whoever you seem to identify with you can find somebody who is good for you.
On the weekly surveys, participants suggested many of the same improvements discussed in the focus group sessions. Suggestions for improvements to the Social POD app included adding more vibrant colors to the app, adding customization such as a personal avatar, integrating a nutrient database, adding the ability to track diet and activity for previous dates, and providing more praise for losing weight and/or increasing physical activity. Additional suggestions made on the weekly surveys not mentioned in the focus groups included adding additional activity options for tracking physical activity (n=1), giving participants the ability to customize the user-to-user messages (n=1), and revising the user-to-user messages to sound more motivating and encouraging (n=1).
A news feed will be developed for the Social POD app for participants to view the progress of other users with weight loss-related goals. Participants will be able to send others encouragement for achieving these goals (eg, logging 30 minutes of exercise, logging diet and weight) through the news feed, targeting positive reinforcement [
Participants lost a mean of 0.94 kg (SD 2.22). Differences in mean participant weight before (91.48 kg, SD 19.08; 95% CI 76.82-106.15) and after (90.55 kg, SD 20.01; 95% CI 75.17-105.93) the 2-month intervention were not statistically significant (
Mean number of Social POD app entries over the course of the 2-month usability study was 77.2 (SD 73.8, 95% CI 17.66-133.68) with a minimum of 0 and a maximum of 219 entries. Messages were sent by frequent users targeting social support most often (32/68, 47%), followed by self-efficacy (28/68, 41%) and outcome expectations (8/68, 12%). There was not a statistically significant correlation between total app entries and percent weight loss over the course of the intervention (
On the weekly surveys, participants reported listening to an average of 2.24 podcast episodes (SD 1.50; minimum 0, maximum 6) per week, and they reported using the Social POD app an average of 4.5 days (SD 2.25; minimum 0, maximum 7). There were 7 reports of problems using the Social POD app by 3 participants over the course of the 2-month study. Reported problems from weekly surveys included spontaneous crashing (2 times) and notifications linking with the incorrect screen in the Social POD app (1 time); there were no explanations for the other reported problems on the weekly surveys.
There were 2 participants with no objective measure of Social POD app use over the course of the study. A participant reported using the Social POD app 1 day during the study, and she specified on the weekly survey that she did not use the app because she did not have enough time. The other participant without objective app use data reported on the weekly surveys that she used the app a total of 21 days during the study. The total number of days participants used the app (as objectively measured by the app) and total number of days of self-reported app use by participants via weekly surveys was highly correlated (
While there has been much work in the area of mobile app development for health, there is currently little published research in the area of development and testing of new mobile apps for weight loss among adults who are overweight and obese. There are several recent studies documenting the development and testing of new apps for weight loss in adolescents [
In a similar mixed-methods usability study, Morrison and colleagues used a computer-based weight loss program in conjunction with an Android mobile app to improve participant goal setting and motivation to achieve weight management goals among young adult participants over a 4-week period [
In a qualitative study examining the desired features of weight loss apps among young adults, Tang and colleagues found that participants valued the opportunity to move beyond strictly tracking their eating behaviors and wanted a way to integrate other features, such as behavioral weight loss goals [
In their qualitative study documenting the development and prototype testing of an app promoting change in eating and activity behaviors to reduce weight gain among young adults, Hebden and colleagues received feedback requesting positive reinforcement for performing desired behaviors (eg, eating healthy foods or engaging in physical activity) [
The color scheme of the Social POD app will be updated with brighter colors to better appeal to users as suggested in the Social POD participant focus groups. Tang and colleagues conducted focus groups with young adult participants and also found that the perceived attractiveness of an app was an important consideration for participant satisfaction and maintaining engagement with weight loss apps [
Ensuring that all components of mHealth apps are functioning properly over time is an integral part of the usability testing process and of great importance in remotely delivered behavioral health interventions. Following usability testing, it was imperative to prioritize the changes that were made to the Social POD app prior to the pilot RCT. Correcting functionality issues and developing a newsfeed and incentive systems took priority; an avatar to personalize the app was not incorporated, and, while a nutrient database was added, it was not as extensive as originally hoped.
Because the purpose of this study was to test the first iteration of the Social POD app prior to the pilot RCT, it was not adequately powered to detect statistically significant differences in pre-post scores. The time period of the study was limited and at 2 months may have been too short to detect significant differences in participant pre-post body weight. The Social POD app is currently only available for the Android operating system. Despite the fact that the Android phone is the most prevalent cell phone in the United States [
One strength of this study was the use of a mixed-methods design, which included participant focus groups to obtain usability and functionality feedback and suggestions for improvements to the Social POD app prior to the pilot RCT. Obtaining feedback through the weekly surveys was another strength, given the potential for some participants to refrain or modify comments during focus groups based on social desirability bias. Another strength of this study was the iterative testing of the Social POD app to uncover and resolve functionality issues prior to the pilot RCT [
The Social POD app provides an innovative way to encourage self-monitoring of dietary intake, weight, and physical activity while encouraging frequent users to provide social support to infrequent users. Although more time is needed for development, this mHealth intervention can be disseminated broadly for many years and to many individuals without the need for additional intensive in-person hours. The Social POD app should be tested in a larger clinical trial for a longer length of time to determine if changes in participant weight, calories consumed, and calories expended during physical activity are improved.
Automated Self-Administered 24-hour Dietary Recall
body mass index
Physical Activity Readiness Questionnaire
randomized clinical trial
Social Pounds Off Digitally
social cognitive theory
This project was supported by the South Carolina Clinical and Translational Research Institute at the Medical University of South Carolina, CTSA NIH/NCATS grant UL1TR000062 to Dr Turner-McGrievy, and NIH grants 1R01GM081793 and P20 RR-016461 to Dr Homayoun Valafar. The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH. The authors would like to thank Lynn Boyd for her contributions to the focus group sessions and transcription of audio recordings.
None declared.