Professional dietary coaching within a group chat using a smartphone application for weight loss: a randomized controlled trial

Abstract

PurposeTo test the effectiveness of professional dietary coaching via group chat using a smartphone application (app) for weight loss.MethodsThis study was a 12-week, assessor-blind, parallel-group, waitlist-controlled randomized trial that included a 4-week follow-up period (trial registration, UMIN000025340). Data were collected between October 2016 and May 2017 and were analyzed between July 2017 and January 2018. Participants were 112 overweight, obese, or abdominally obese Japanese adults, aged 20 to 64 years, with at least one cardiometabolic risk factor. Participants were randomized to the coaching group (n=75) or control group (n=37), with a ratio of 2:1. The coaching group received a commercial weight loss program characterizing dietary coaching by a certified nutrition professional via group chat delivered on a smartphone app. Participants posted photos of every meal into the group chat, and the certified professional gave immediate direct feedback and encouragement. The primary outcome was an 8-week weight change. Secondary outcomes included 8-week changes in cardiometabolic risk factors. The frequency of meal photo uploads was recorded as a measure of adherence.ResultsOf the 112 randomized participants, 93 (83.0%) and 81 (72.3%) completed 8-week and 12-week visits, respectively. Intention-to-treat analysis demonstrated significantly larger 8-week weight loss in the coaching group (−1.4 kg; 95% confidence interval [CI]: −2.0, −0.8 kg) than that in the control group (−0.1 kg; 95% CI: −0.6, 0.4 kg). Significantly larger improvements in triglyceride and glycated hemoglobin A1c levels were also obtained in the coaching group. These benefits, except for the triglyceride level, were maintained until week 12. The frequent upload of meal photos was associated with a larger 8-week weight loss in a dose–response fashion (P-value for trend <0.001).ConclusionThis smartphone-delivered commercial weight loss program characterized as dietary coaching via group chat resulted in modest but significant weight loss. Facilitating participants’ active involvement in the program is necessary to achieve greater health benefits.

User Engagement With Smartphone Apps and Cardiovascular Disease Risk Factor Outcomes: Systematic Review (Preprint)

“…The study characteristics are summarized in Multimedia Appendix 2 . Of the 24 studies, 17 used an RCT design [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], 4 used a retrospective analysis [33][34][35][36], and 3 used a single-group pre-and posttest quasi-experimental design [37][38][39]. Although 20 studies used an RCT or single-group preand-posttest quasi-experimental design, it was the correlational studies nested within these larger parent studies that were of interest for this review.…”

“…Of the 17 RCT studies, 14 conducted an a priori power analysis. Of these 14 RCTs, 3 detected a significant difference in the primary outcome between groups [21,23,27], 9 did not detect a significant difference in the primary outcome between groups [16,17,22,[24][25][26]29,31,32], and 2 did not report the results of the difference in the primary outcome between groups [18,30]. One of the studies that did not detect a significant difference between groups did not achieve the target sample size [32].…”

“…All 24 studies reported on sex, with 16 of the samples consisting largely of women (range 51%-91%) [22,38], 7 of the samples consisting largely of men (range 51%-100%) [16,21], and one split evenly [39]. Thirteen studies reported sample races [17][18][19][21][22][23][24][25][26][27][28]32,39], with 7 consisting largely of White participants [18,19,22,[24][25][26]28]. Seventeen studies reported on sample educational level, with the majority of the participants within each individual study having attended some college [16][17][18][19][20][21][22][23][24][25][26][28][29][30][31][32]38,39].…”

“…Seventeen studies reported on sample educational level, with the majority of the participants within each individual study having attended some college [16][17][18][19][20][21][22][23][24][25][26][28][29][30][31][32]38,39]. Ten studies limited their sample to participants who were overweight or obese [17,19,[21][22][23][24][25][26]28,35], and another 11 studies reported enrolling participants with a baseline mean or majority percentage BMI indicating overweight or obesity [16,20,22,27,[29][30][31]33,34,38,39]. The majority of the studies recruited participants from a community setting, except for 5 studies that recruited participants from hospitals [21], a hospital-based diabetes management education program [32], primary care [23,29], and a community health care facility [39].…”

“…All 22 interventions assessed included an app for addressing CVD risk factors. Of 22 interventions, 11 (50%) included commercial apps [19,20,22,[25][26][27][32][33][34][35][36][37]39] and 11 (50%) included investigator-developed apps [16][17][18]21,23,24,[28][29][30][31]38]. In addition, 73% (16/22) of the interventions consisted of not only an app but also other components, including in-person meetings, emails, text messaging, phone consults, websites, Facebook groups, blogs, and podcasts [16][17][18][19][20][21][22][23][24][25][26][29][30][31]36,38,39].…”