Intervention content was adapted from the original Fresh Start intervention, a weight loss treatment protocol based on content from the DPP [11], adapted for mothers with young children [14,33]. Briefly, the original Fresh Start protocol involved an 8-week group-based curriculum delivered by a WIC nutritionist. The intervention format included a narrative component, group discussions, print materials, and access to fitness facilities, followed by 9 monthly follow-up telephone calls.

This intervention was adapted for delivery via Facebook. First, the research team held regular meetings to review the protocol for the in-person Fresh Start Trial [33], which was adapted from the DPP curriculum [34]. The team identified key constructs and topics from the sessions and created a draft library of Facebook posts that were originally copied verbatim from the in-person protocol. In accordance with the Fresh Start protocol [33], posts emphasized one new topic each week (eg, tracking food and beverage intake, reading nutrition labels) and the use of behavioral strategies including self-monitoring and goal setting. The language was then simplified, and messages were shortened into simple terms and short sentences. The adaptation process for the Facebook intervention using goal setting as an example as well as a collage of posts can be found in Multimedia Appendix 1 and Multimedia Appendix 2. As research has shown that Facebook engagement is higher when a post has a photo or video [19,35], videos and pictures from the in-person protocol were included in posts where applicable and supplemented by additional photos, infographics, and videos extracted from Web-based sources with special attention to maintaining the original message. These were created using Microsoft Publisher and Windows Media Player. To promote interaction among participants in the Facebook group, all posts ended with an open-ended question regarding the topic of the post [19]. Facebook posts were then systematically ordered into a “feed” based on the order and progression of the original protocol and previous social media marketing research reporting an ideal frequency of 1-2 Facebook posts per day [19,35].

Finally, 8 research staff members with experience in weight loss intervention and social media approaches participated in a mock Facebook group where posts were delivered and pilot-tested. These individuals were asked to provide feedback on the wording of the posts, including the language, pictures, and videos, and whether the posts emphasized behavioral weight loss strategies and principles of motivational interviewing. Posts were revised and finalized for the first pilot based on feedback from the mock group.

The intervention consisted of an 8-week intervention phase followed by an 8-week maintenance phase delivered via a secret, private Facebook group, preceded by a 90-minute in-person orientation session. Each of the 3 pilots held 2 orientation sessions (one in the morning and one in the evening) that women attended based on their needs, and sessions were required for participation in the study. The orientation allowed women to meet other women in their Facebook group, provided instruction on how to join the Facebook group, and informed women about the rules of the Facebook group.

Women were also introduced to the concepts of goal setting and taught how to track their diet, physical activity, and weight loss using a commercial mobile app (MyFitnessPal) or paper records. They were also provided a scale, pedometer, workbook, measuring cups, and a 1-year gym membership to YWCA Central Massachusetts at no cost to them.

Following the orientation, participation in the Facebook intervention commenced. During the first 8 weeks, Facebook intervention posts were delivered 2 times per day (8 am and 4 pm), 7 days per week, from study-created Facebook accounts (one from the intervention coach and one from the assistant coach) via the social media management platform Buffer [22]. The intervention coach was a postdoctoral fellow with experience and training in behavioral weight loss intervention delivery, and the assistant coach was a doctoral student. The coaching tasks included liking and commenting on the women’s posts or comments, encouraging discussion and sharing of strategies to deal with challenges to goal attainment or weight loss among the women, answering questions, and providing support. Coaches also provided group-based feedback based on women’s answers to intervention prompts. For the second 8-week period of the intervention (weeks 9-16), Facebook posts were delivered once per day without additional input from coaches.

Outcome measures for each pilot study focused on feasibility outcomes including retention, engagement, and satisfaction. [36]. Weight change also was assessed. Participants completed the survey and anthropometric measures at baseline (preintervention assessment) and 16-week follow-up (postintervention assessment). Additional engagement data were obtained from Facebook, as described below. Participants who completed the postintervention assessment received a $50 gift card incentive.

Height and weight were measured at baseline and after 16 weeks by trained research staff using a stadiometer and digital scale, respectively, with participants removing their shoes.

As in previous studies [19,22,23], engagement was operationalized as participants’ behavior and interactions with the Facebook group, including all likes, comments, and posts in each week. Facebook data were downloaded weekly using Facebook Downloader V5.0.1, and it included the number of comments, likes, and original posts from each participant over the course of the intervention. Additional survey questions asked women to self-report their level of engagement with a series of items that inquired how often they read the entire intervention posts and how often they read part of the intervention posts. Response options were on a 6-point scale ranging from “never (0% of the time)” to “almost always or always (90%-100% of the time).” Indiscernible Facebook engagement, or “lurking,” was also defined via the extent to which women read the intervention posts without commenting on it or liking it [37]. Specifically, women reported how often they read the entire post and did not respond by liking it or commenting on it on a 5-point scale ranging from “never” to “always.”

Survey items at the follow-up assessment asked about satisfaction with the intervention overall and satisfaction with the amount of weight lost during the program. Responses were rated on a 5-point scale ranging from “very dissatisfied” to “very satisfied.” Women also rated how helpful they found the program in helping them lose weight on a 5-point scale from “very unhelpful” to “very helpful.” We asked the participants how likely they were to participate in a similar weight loss program and how likely they were to recommend the program to a friend on a 5-point scale from “very unlikely” to “very likely.” Women also rated how often they felt supported by other participants in the group on a 5-point scale ranging from “never” to “always.” Finally, women rated the extent to which they felt the other participants were motivating and the extent to which they felt the coaches were helpful and motivating based on a 5-point scale from “strongly disagree” to “strongly agree.”

A total of 29 women were initially enrolled in Pilot 1. However, 2 participants became ineligible during the intervention, one due to medical reasons and the other due to intake of a weight-altering medication (study exclusion criterion). Thus, the final sample for Pilot 1 was 27 women (Table 1). The retention rate for this pilot was 89% (24/27).

Table 2 displays the engagement for all 3 pilots during the coached (weeks 1-8) and noncoached (weeks 9-16) phases of the intervention. On average, about 63% (17/27) women engaged in the group each week. Of the 24 women who completed the 16-week assessment, 71% (17/24) reported reading the entire intervention posts either most of the time or always and 42% (10/24) said that they read only part of the posts either most of the time or always. When asked about lurking, 1 woman reported never reading a post without commenting on it or liking it; 38% (9/24) women reported occasionally reading a post without commenting on it or liking it; 17% (4/24) women reported lurking half the time, 21% (5/24) women much of the time, and 21% (5/24) women always.

Weight loss outcomes at the 16-week follow-up are presented in Table 3. Women lost an average of 2.6 (SD 8.64; range −23.4 to 14.4) pounds or 1.4% of their baseline weight (SD 4.4; range −12.4 to 5.8). At the 16-week follow-up, 63% (15/24) women lost weight and 38% (9/24) women gained weight.

A majority (75%, 18/24) of the participants reported being satisfied or very satisfied with the intervention, and 19 out of 24 women (79.2%) felt the program was somewhat or very helpful in facilitating their weight loss (Table 3). Furthermore, 63% (15/24) women felt supported by other participants in the group at least half of the time, and 67% (16/24) felt that the other women in the group were motivating. Finally, all 24 women (100%) felt that the coaches were helpful and motivating.

We learned several key lessons from Pilot 1 based on the group discussions and Facebook group engagement data. First, we explored intervention posts with lower engagement, as defined by <5 comments on the post or <3 women who commented on the post, to identify key themes or similarities between posts with poor engagement. From our review of engagement data, we discerned that goal setting posts, posts with lengthy videos, and posts asking multiple questions were associated with lower engagement among the participants. As a result, we edited goal posts to include sample goals, exchanged long videos for infographics, and reduced the word count of lengthier posts to simplify the posts further. Of note, when iterations were made to the approach to behavioral strategies, the core evidence-based behavioral strategies were maintained across groups. During the group discussions, we learned that women were more likely to read and comment on a post that included helpful pictures and visuals. For example, a few of the women shared that they took “screenshots” of the intervention pictures and saved them to the photo library on their mobile phones to be able to access them later. We therefore carefully reviewed intervention posts that included photos (eg, a picture of a mom walking) versus infographics (eg, a diagram of healthy snacks with calorie amounts), and where applicable, we enhanced posts to include infographics.

Second, during the first few weeks of the intervention, women reported via Facebook posts to the group and private messages to the coaches that they were having difficulties tracking their diet or activity using the recommended app (ie, MyFitnessPal). We thus modified intervention posts during the first 2 weeks to include posts that provided support in learning to use the app. Specifically, we created 4 new Facebook posts for Pilot 2 that included both videos and infographics and directed women on key features of tracking their food using the app.

Finally, during the group discussions, women reported that they wished there were more opportunities for the participants to meet in person and suggested that this be accomplished via increased utilization of the free YWCA membership. Based upon this suggestion that in-person interactions be in the form of workout groups or other exercise participation, during the coached phase of Pilot 2, participants received Facebook posts with invitations to join and participate in an exercise class at the YWCA with other women in the group and one of the coaches. Class type (eg, Zumba, yoga) and day and time varied each week to facilitate the attendance of women with different scheduling needs.

Pilot 2 had initially enrolled 25 participants. However, 1 woman became ineligible due to pregnancy, leading to a sample of 24 women (Table 1). The retention rate for this pilot was 83% (20/24).

An average of 13 (55.2%) women engaged in the group each week. Of the 20 women who completed the 16-week assessment, 70% (14/20) reported reading the entire intervention post either most of the time or always, and 65% (13/20) women said that they read only part of the post most of the time or always. When asked about lurking behavior, 35% (7/20) women reported occasionally reading a post without commenting on it or liking it; 25% (5/20) women reported lurking half the time, 25% (5/20) women much of the time, and 5% (120) woman always.

Women lost an average of 2.5 (SD 9.23; range −26.2 to 8.8) pounds or 1.2% of their baseline weight (SD 3.97; range −9.8 to 3.8; Table 3). Half (10/20, 50%) of the women lost weight, 5% (1/20) woman maintained her baseline weight, and 45% (9/20) women gained weight.

A majority (16/20, 80%) of the women reported being satisfied or very satisfied with the intervention, and 60% (12/20) women felt the program was somewhat or very helpful in their weight loss effort. Furthermore, 65% (13/20) women felt supported by other women in the group at least half of the time, and 60% (12/20) women felt the other women in the group were motivating. Finally, 90% (18/20) women felt that the coaches were helpful, and 95% (19/20) women felt that the coaches were motivating.

Observations and findings from Pilot 2 provided additional insight on how to enhance the intervention. First, women endorsed opportunities to attend group exercise classes with one of the intervention coaches at the YWCA. However, only 3 of the women ever attended these classes. Challenges to attendance included lack of time, class timings not working well with their schedules, and childcare responsibilities (babysitting). Second, women expressed that they wished more women would have engaged actively in the Facebook group. Factors that got in the way of active engagement included feeling uncomfortable posting about themselves and not wanting to post if they were not experiencing successful weight loss. In terms of intervention content, women expressed that they were less likely to read posts that were too long and endorsed posts that elicited responses via questions and included visuals. Examples of helpful visuals included pictures of appropriate portion sizes, recipe substitution ideas, and number of calories of specific commonly consumed foods.

From the lessons learned in Pilot 2, we made several modifications for Pilot 3. First, we again carefully reviewed the posts based on the women’s feedback, as well as posts that elicited low engagement (<5 comments or <3 women commenting). We adjusted the language to make them more concise and engaging, and where applicable, we replaced some of the text with a picture or video. In response to feedback regarding the use of gym, we extended the orientation by 5 minutes to include more information about the YWCA and provide women with a map to the facility and the group exercise schedule. We were also able to secure babysitting at the YWCA for 2 hours, 3 days per week: 1 day in the morning, 1 day in early afternoon, and 1 day in the late afternoon or early evening. To encourage women to post more in the group, we added 2 posts in the first week of the intervention; one asked women to introduce themselves to the group and one encouraged women to post in the group regardless of their motivation throughout the program (eg, when they lost weight vs when they did not lose weight; when they had a good week vs when they had a bad week).

Pilot 3 had 17 enrolled participants. However, 1 woman became ineligible during the study due to a new pregnancy, leading to a final sample of 16 women (Table 1). The retention rate in Pilot 3 was 88% (14/16).

On average, 67% (11/16) women engaged in the group each week. Out of the 14 women who completed the 16-week assessment, 43% (6/14) women reported reading the entire intervention post most of the time or always (≥75% of the time), and 43% (6/14) said that they read part of the post most of the time or always. When asked about lurking behavior, 36% (5/14) women reported occasionally reading a post without commenting on it or liking it; 21% (3/14) women reported lurking half the time, 36% (5/14) women much of the time, and 7% (1/14) woman always.

During Pilot 3, women lost an average of 7.0 (SD 11.6; range −31.8 to 13.8) pounds or 3.6% of their baseline weight (SD 5.62, range −11.9 to 6.1; Table 3). Out of 14 women, 71% (10/14) women lost weight, 14% (2/14) women maintained their baseline weight, and 14% (2/14) women gained weight.

A majority (9/14, 64.3%) of the women reported being satisfied or very satisfied with the intervention, and 79% (11/14) women felt the program was somewhat or very helpful for their weight loss effort. Furthermore, 64% (9/14) women felt supported by other women in the group at least half of the time, and 57% (8/14) women felt the other women in the group were motivating. Finally, all 14 (100%) women felt that the coaches were helpful and 93% (13/14) women felt that the coaches were motivating.

We learned several key lessons from the women in Pilot 3. Women reported that they would have liked there to be more interaction among the women in the group, and a few suggested more opportunities for in-person meetings or get-togethers (eg, Pilates in the park, walking around the neighborhood). However, like Pilot 2, a discrepancy existed between these suggestions and attendance in in-person group opportunities, as none of the women in Pilot 3 utilized the babysitting or attended the classes at the YWCA with one of the coaches. Women also reported several factors that contributed to their engagement with the Facebook group, including the time of day of the post, how much time had passed since the post, and how many other women had commented on the post. Women also offered several suggestions for improving communication between each other within the Facebook group, such as exchanging phone numbers during the orientation session, having nonweight loss related ice breakers on the Facebook group (eg, asking about work schedules or how many kids women have), and having weekly step or weight loss competitions. Finally, women provided feedback on intervention content and reported that they found practical tips related to meal planning, proper food storage, food preparation, and recipes to be particularly helpful.

Based on the findings and feedback from Pilot 3, as well as Pilots 1 and 2, important lessons that could inform further intervention refinement were the intervention posts that included concise language; open-ended questions that elicited responses; infographics and content related to weight loss progress, calorie goals and budgeting; and practical tips for meal planning and cooking. Furthermore, while women in all 3 pilots liked receiving the intervention content via Facebook, they desired more social support from one another and suggested solutions, such as a longer orientation session, more ice breakers and discussions on Facebook, and face-to-face interactions to facilitate this support. It is important to note, however, that when women in these pilots were offered more opportunities for in-person interaction, they did not utilize them.