Abstract
Physical inactivity and obesity are detrimental to one's overall health, as they increase the risk of developing non-communicable diseases. Fortunately, physical inactivity and obesity can be improved by supporting lifestyle behavior changes. This support may be provided remotely by Mobile Health (mHealth) messaging interventions, which involve using mobile messages for health improvement. This study aimed to determine the effect of mHealth interventions using unidirectional text messaging/instant messaging on physical activity and weight-related outcomes in adult populations. An electronic literature search was conducted using PubMed, Scopus, and Web of Science, for pre-post interventions using unidirectional messaging for physical activity/weight loss. A total of 43 articles were included in the review. Most studies used non-tailored text messages, were RCTs, and were performed on clinical populations in high income countries. Meta-analysis showed that messages had minimal effects on physical activity (d+: .14, 95% CI: .05 to .23, P = .003, I(2) = 65%), and no effect on weight loss (d+: .04, 95% CI: -.02 to .10, P = .21, I(2) = 29%). This suggests that unidirectional messaging alone is not sufficient to promote physical activity and weight loss. Future studies should consider using bidirectional messaging or other interventions in addition to messages, such as mobile applications, to potentially improve intervention effectiveness.