title: Efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour: a systematic review.
abstract: BACKGROUND
  Health and fitness applications (apps) have gained popularity in interventions to improve diet, physical activity and sedentary behaviours but their efficacy is unclear. This systematic review examined the efficacy of interventions that use apps to improve diet, physical activity and sedentary behaviour in children and adults.
  
  
  METHODS
  Systematic literature searches were conducted in five databases to identify papers published between 2006 and 2016. Studies were included if they used a smartphone app in an intervention to improve diet, physical activity and/or sedentary behaviour for prevention. Interventions could be stand-alone interventions using an app only, or multi-component interventions including an app as one of several intervention components. Outcomes measured were changes in the health behaviours and related health outcomes (i.e., fitness, body weight, blood pressure, glucose, cholesterol, quality of life). Study inclusion and methodological quality were independently assessed by two reviewers.
  
  
  RESULTS
  Twenty-seven studies were included, most were randomised controlled trials (n = 19; 70%). Twenty-three studies targeted adults (17 showed significant health improvements) and four studies targeted children (two demonstrated significant health improvements). Twenty-one studies targeted physical activity (14 showed significant health improvements), 13 studies targeted diet (seven showed significant health improvements) and five studies targeted sedentary behaviour (two showed significant health improvements). More studies (n = 12; 63%) of those reporting significant effects detected between-group improvements in the health behaviour or related health outcomes, whilst fewer studies (n = 8; 42%) reported significant within-group improvements. A larger proportion of multi-component interventions (8 out of 13; 62%) showed significant between-group improvements compared to stand-alone app interventions (5 out of 14; 36%). Eleven studies reported app usage statistics, and three of them demonstrated that higher app usage was associated with improved health outcomes.
  
  
  CONCLUSIONS
  This review provided modest evidence that app-based interventions to improve diet, physical activity and sedentary behaviours can be effective. Multi-component interventions appear to be more effective than stand-alone app interventions, however, this remains to be confirmed in controlled trials. Future research is needed on the optimal number and combination of app features, behaviour change techniques, and level of participant contact needed to maximise user engagement and intervention efficacy.
authors.affiliation: Central Queensland University, School of Health, Medical and Applied Sciences, Physical Activity Research Group, Building 77, Bruce Highway, Rockhampton, QLD 4702, Australia. s.schoeppe@cqu.edu.au.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schoeppe
authors.affiliation: Central Queensland University, School of Health, Medical and Applied Sciences, Physical Activity Research Group, Building 77, Bruce Highway, Rockhampton, QLD 4702, Australia.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Alley
authors.affiliation: Ghent University, Department of Public Health, De Pintelaan 185-4 K3 room 036, 9000, Ghent, Belgium.
authors.forename: Wendy
authors.initials: W
authors.lastname: Van Lippevelde
authors.affiliation: Central Queensland University, School of Health, Medical and Applied Sciences, Physical Activity Research Group, Building 77, Bruce Highway, Rockhampton, QLD 4702, Australia.
authors.forename: Nicola A
authors.initials: NA
authors.lastname: Bray
authors.affiliation: Central Queensland University, School of Health, Medical and Applied Sciences, Building 6, Bruce Highway, Rockhampton, QLD 4702, Australia.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Williams
authors.affiliation: The University of Newcastle, School of Medicine & Public Health, Priority Research Centre for Physical Activity and Nutrition, University Drive, Callaghan, NSW 2308, Australia.
authors.forename: Mitch J
authors.initials: MJ
authors.lastname: Duncan
authors.affiliation: Central Queensland University, School of Health, Medical and Applied Sciences, Physical Activity Research Group, Building 77, Bruce Highway, Rockhampton, QLD 4702, Australia.
authors.forename: Corneel
authors.initials: C
authors.lastname: Vandelanotte
mesh_terms: D000328:Adult; D002648:Child; D004032:Diet; D015444:Exercise; D015438:Health Behavior; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D063731:Mobile Applications; D057185:Sedentary Behavior; D000068997:Smartphone
keywords: Efficacy; Exercise; Health behaviour; Healthy eating; Literature searches; Programs; Sitting; Smartphone applications; Systematic review