Efficacy of a Text Message-Delivered Extended Contact Intervention on Maintenance of Weight Loss, Physical Activity, and Dietary Behavior Change

JMIR Mhealth Uhealth. 2015 Sep 15;3(3):e88. doi: 10.2196/mhealth.4114.


Background: Extending contact with participants after the end of an initial intervention is associated with successful maintenance of weight loss and behavior change. However, cost-effective methods of extending intervention contact are needed.

Objective: This study investigated whether extended contact via text message was efficacious in supporting long-term weight loss and physical activity and dietary behavior change in breast cancer survivors.

Methods: Following the end of an initial 6-month randomized controlled trial of a telephone-delivered weight loss intervention versus usual care, eligible and consenting intervention participants received a 6-month extended contact intervention via tailored text messages targeting a range of factors proposed to influence the maintenance of behavior change. In this single-group, pre-post designed study, within group changes in weight, moderate-to-vigorous physical activity (Actigraph GT3X+ accelerometers), and total energy intake (2x24 hour dietary recalls) were evaluated from baseline to end of initial intervention (6 months), end of extended contact intervention (12 months), and after a no-contact follow-up (18 months) via linear mixed models. Feasibility of implementation was assessed through systematic tracking of text message delivery process outcomes, and participant satisfaction was assessed through semistructured interviews.

Results: Participants at baseline (n=29) had a mean age of 54.9 years (SD 8.8), body mass index of 30.0 kg/m(2) (SD 4.2), and were recruited a mean 16.6 months (SD 3.2) post diagnosis. From baseline to 18 months, participants showed statistically significantly lower mean weight (-4.2 kg [95% CI -6.0 to -2.4]; P<.001) and higher physical activity (mean 10.4 mins/day [95% CI 3.6-17.2]; P=.003), but no significant differences in energy intake (P=.200). Participants received a mean of 8 text messages every 2 weeks (range 2-11) and reported a high rate of satisfaction.

Conclusions: In comparison to interventions without extended contact, results suggest text message-delivered extended contact may support the attenuation of weight regain and promote the maintenance of physical activity.

Keywords: SMS; behavior change; diet; intervention; maintenance; mhealth; mobile telephone; physical activity; textmessaging; weight.