Efficacy of SmartLoss, a smartphone-based weight loss intervention: results from a randomized controlled trial

Abstract

Objective: Test the efficacy of SmartLoss, a smartphone-based weight loss intervention, in a pilot study.

Design and methods: A 12-week randomized controlled trial. Adults (25 ≤ BMI ≤ 35 kg/m2) were randomized to SmartLoss (n = 20) or an attention-matched Health Education control group (n = 20). SmartLoss participants were prescribed a 1,200 to 1,400 kcal/d diet and were provided with a smartphone, body weight scale, and accelerometer that wirelessly transmitted body weight and step data to a website. In the SmartLoss Group, mathematical models were used to quantify dietary adherence based on body weight and counselors remotely delivered treatment recommendations based on these objective data. The Health Education group received health tips via smartphone. A mixed model determined if change in weight and other endpoints differed between the groups (baseline was a covariate).

Results: The sample was 82.5% female. Mean ± SD baseline age, weight (kg), and BMI were 44.4 ± 11.8 years, 80.3 ± 11.5 kg, and 29.8 ± 2.9 kg/m2, respectively. One participant was lost to follow-up in each group before week 4. Weight loss was significantly (P < 0.001) larger in the SmartLoss (least squares mean ± SEM: -9.4 ± 0.5%) compared with the Health Education group (-0.6 ± 0.5%).

Conclusions: SmartLoss efficaciously promote clinically meaningful weight loss compared with an attention-matched control group. Smartphone-based interventions might prove useful in intervention dissemination.

Trial registration: ClinicalTrials.gov NCT00883350.

Figure 1

Diagram describing recruitment and study flow.

Figure 2

The weight graph or nomogram. Participants are considered adherent to the caloric prescription if their body weight is within the “zone” depicted on the weight graph. Additionally, mean energy intake over time can be accurately calculated based on observed body weight.

Figure 3

Change from baseline (least square means) for the primary outcome variables (error bars represent standard errors of the mean). The solid line and dashed lines represent the SmartLoss and Health Education Control groups, respectively. Asterisks indicate significant within group change from baseline (*P<.05, **P<.01, ***P<.001). Plus signs indicate significant differences between groups on change from baseline (+P<.05, ++P<.01, +++P<.001).

Figure 4

Weight change over 12 weeks per individual in the Health Education (Panel A) and SmartLoss (Panel B) group.

Figure 5

Weight loss nomograms that are normalized to reflect the distance in or out of the zone for men and women. Panels A and B include the individual and group level data for men, respectively. Panels C and D include the individual and group level data for women, respectively. As illustrated, men were, as a group, more frequently in the zone compared to women.