title: Factors related to sustained use of a free mobile app for dietary self-monitoring with photography and peer feedback: retrospective cohort study.
abstract: BACKGROUND
  Healthy eating interventions that use behavior change techniques such as self-monitoring and feedback have been associated with stronger effects. Mobile apps can make dietary self-monitoring easy with photography and potentially reach huge populations.
  
  
  OBJECTIVE
  The aim of the study was to assess the factors related to sustained use of a free mobile app ("The Eatery") that promotes healthy eating through photographic dietary self-monitoring and peer feedback.
  
  
  METHODS
  A retrospective analysis was conducted on the sample of 189,770 people who had downloaded the app and used it at least once between October 2011 and April 2012. Adherence was defined based on frequency and duration of self-monitoring. People who had taken more than one picture were classified as "Users" and people with one or no pictures as "Dropouts". Users who had taken at least 10 pictures and used the app for at least one week were classified as "Actives", Users with 2-9 pictures as "Semi-actives", and Dropouts with one picture as "Non-actives". The associations between adherence, registration time, dietary preferences, and peer feedback were examined. Changes in healthiness ratings over time were analyzed among Actives.
  
  
  RESULTS
  Overall adherence was low-only 2.58% (4895/189,770) used the app actively. The day of week and time of day the app was initially used was associated with adherence, where 20.28% (5237/25,820) of Users had started using the app during the daytime on weekdays, in comparison to 15.34% (24,718/161,113) of Dropouts. Users with strict diets were more likely to be Active (14.31%, 900/6291) than those who had not defined any diet (3.99%, 742/18,590), said they ate everything (9.47%, 3040/32,090), or reported some other diet (11.85%, 213/1798) (χ(2) 3=826.6, P<.001). The average healthiness rating from peers for the first picture was higher for Active users (0.55) than for Semi-actives (0.52) or Non-actives (0.49) (F2,58167=225.9, P<.001). Actives wrote more often a textual description for the first picture than Semi-actives or Non-actives (χ(2) 2=3515.1, P<.001). Feedback beyond ratings was relatively infrequent: 3.83% (15,247/398,228) of pictures received comments and 15.39% (61,299/398,228) received "likes" from other users. Actives were more likely to have at least one comment or one "like" for their pictures than Semi-actives or Non-actives (χ(2) 2=343.6, P<.001, and χ(2) 2=909.6, P<.001, respectively). Only 9.89% (481/4863) of Active users had a positive trend in their average healthiness ratings.
  
  
  CONCLUSIONS
  Most people who tried out this free mobile app for dietary self-monitoring did not continue using it actively and those who did may already have been healthy eaters. Hence, the societal impact of such apps may remain small if they fail to reach those who would be most in need of dietary changes. Incorporating additional self-regulation techniques such as goal-setting and intention formation into the app could potentially increase user engagement and promote sustained use.
authors.affiliation: Department of Signal Processing, Tampere University of Technology, Tampere, Finland. elina.helander@tut.fi.
authors.forename: Elina
authors.initials: E
authors.lastname: Helander
authors.forename: Kirsikka
authors.initials: K
authors.lastname: Kaipainen
authors.forename: Ilkka
authors.initials: I
authors.lastname: Korhonen
authors.forename: Brian
authors.initials: B
authors.lastname: Wansink
mesh_terms: D000328:Adult; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D063731:Mobile Applications / Q000706:statistics & numerical data*; D010349:Patient Compliance; D010352:Patient Dropouts; D010379:Peer Group; D010781:Photography; D012189:Retrospective Studies; D012648:Self Care
keywords: adherence; control theory; food journaling; food photographing; healthy eating; mobile app; peer feedback; self-monitoring
references.citation: Proc Nutr Soc. 2013 Feb;72(1):70-6
references.pmid: 23336561
references.citation: Eur J Clin Nutr. 2009 Feb;63 Suppl 1:S50-7
references.pmid: 19190645
references.citation: J Am Diet Assoc. 2007 Oct;107(10):1807-10
references.pmid: 17904942
references.citation: Ann Behav Med. 2009 Dec;38 Suppl 1:S4-17
references.pmid: 19787308
references.citation: Appetite. 2009 Feb;52(1):127-36
references.pmid: 18835305
references.citation: J Am Diet Assoc. 2011 Jan;111(1):92-102
references.pmid: 21185970
references.citation: Physiol Behav. 2014 Jul;134:55-9
references.pmid: 24589367
references.citation: J Med Internet Res. 2013 Jun 24;15(6):e125
references.pmid: 23796439
references.citation: J Med Internet Res. 2013 Jan 15;15(1):e11
references.pmid: 23322819
references.citation: Health Psychol. 2009 Nov;28(6):690-701
references.pmid: 19916637
references.citation: IEEE J Sel Top Signal Process. 2010 Aug;4(4):756-766
references.pmid: 20862266
references.citation: J Hum Nutr Diet. 2003 Jun;16(3):181-8
references.pmid: 12753111
references.citation: Psychol Bull. 1982 Jul;92(1):111-35
references.pmid: 7134324
references.citation: J Am Diet Assoc. 2010 Jan;110(1):55-64
references.pmid: 20102828
references.citation: Am J Health Promot. 2006 Jan-Feb;20(3):165-70
references.pmid: 16422134
references.citation: J Am Diet Assoc. 2010 Jan;110(1):48-51
references.pmid: 20102826
references.citation: J Biomed Inform. 2012 Feb;45(1):184-98
references.pmid: 21925288
references.citation: J Med Internet Res. 2011 Feb 14;13(1):e17
references.pmid: 21320854
references.citation: Annu Rev Nutr. 2004;24:455-79
references.pmid: 15189128
references.citation: Contemp Clin Trials. 2008 Mar;29(2):182-93
references.pmid: 17702667
references.citation: J Med Internet Res. 2012 Nov 14;14(6):e152
references.pmid: 23151820
references.citation: J Med Internet Res. 2011 Jan 06;13(1):e2
references.pmid: 21212045
references.citation: J Med Internet Res. 2005 Mar 31;7(1):e11
references.pmid: 15829473
references.citation: J Med Internet Res. 2012 Apr 13;14(2):e58
references.pmid: 22504018
references.citation: Am J Prev Med. 2008 Aug;35(2):118-26
references.pmid: 18617080
references.citation: Obesity (Silver Spring). 2008 Aug;16(8):1826-30
references.pmid: 18551108
references.citation: J Diabetes Sci Technol. 2012 Mar 01;6(2):428-34
references.pmid: 22538157
references.citation: Obes Res. 2003 Aug;11(8):945-9
references.pmid: 12917498