Table Of ContentEFFECT OF AN ONLINE SOCIAL NETWORK ON PERCEIVED SOCIAL SUPPORT
AND SELF-EFFICACY TO ADOPT AND MAINTAIN HEALTH BEHAVIORS
A Thesis
presented to
the Faculty of California Polytechnic State University,
San Luis Obispo
In Partial Fulfillment
of the Requirements for the Degree
Master of Science in Agriculture,
Specialization in Food Science and Nutrition
by
Caitlin Kingston Leff
June 2011
© 2011
Caitlin Kingston Leff
ALL RIGHTS RESERVED
ii
COMMITTEE MEMBERSHIP
TITLE: Effect of an Online Social Network on Perceived Social
Support and Self-Efficacy to Adopt and Maintain Health
Behaviors
AUTHOR: Caitlin Kingston Leff
DATE SUBMITTED: June 2011
COMMITTEE CHAIR: Dr. Lisa Nicholson, Associate Professor
Food Science and Nutrition
COMMITTEE MEMBER: Dr. Ann McDermott, Associate Professor
Kinesiology
COMMITTEE MEMBER: Dr. Scott Reaves, Associate Professor
Food Science and Nutrition
iii
ABSTRACT
Effect of an Online Social Network on Perceived Social Support and Self-Efficacy
to Adopt and Maintain Health Behaviors
Caitlin Kingston Leff
Objective: The purpose of this pilot study was to examine the effect of an online social
network used as an adjunct to a behavioral weight loss intervention on participants‟
perceived social support and perceived self-efficacy using constructs of Social Cognitive
Theory as a basis for website development.
Methods: 13 adult women (mean age: 43 years of age, range: 25-63 years) participated in
a 12-week behavioral weight-loss intervention with the option to access the
Transformation Challenge Online Community (TCOC), an internet-based support and
informational website. The TCOC was developed using constructs of the Social
Cognitive Theory. Data analyzed included online site usage software and pre- and post-
questionnaire results. Time spent online, unique visits to the webpage, and pre and post-
intervention data were analyzed using a mixed methods approach.
Results: Average time spent on TCOC was 95.6 minutes over the entire three month
intervention (range: 0 – 287 minutes). Website usage varied widely ranging from a
participant who never accessed the site to another participant who logged on daily and
commented a total of 27 times. Perceived self-efficacy to maintain a learned health
behavior without the aid of a professional, as well as overall perceived social support
were statistically significantly greater post-intervention. Confidence in the TCOC‟s
ability to aid in making healthy lifestyle changes decreased significantly from pre- to
post-intervention while website usage also decreased over time.
Conclusions: The internet may be a valuable tool for improving perceptions of social
support and increasing access to reliable information and education. A web-based
intervention can be used as an adjunct to a face-to-face intervention to provide additional
support and information, as well as used to reach groups who may not have access to a
face-to-face option. Considerations should be given to the structure of the online
program; the potential for dynamic, aesthetically pleasing self-regulation tools; and
content that is tailored to the individual. Decreased usage of the website over time may
reflect similar difficulties in maintaining participation in face-to-face weight loss
interventions. Attention should also be given to the target audience as participant
comfort levels and feelings towards using the internet may differ significantly between
users and therefore impact outcomes.
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AKNOWLEDGMENTS
The personal and professional growth I have experienced over the past few years
as a Cal Poly graduate student, as well as the development of this research project would
not have been possible without the generous time and support provided by several very
important people. I would like to take the time to thank them.
First and foremost I would like to thank my Committee Chair and Graduate
Advisor, Dr. Lisa Nicholson, whose continued belief in my potential has helped shape the
nutrition professional I am today. I am so thankful to have been able to work so closely
with such an inspirational woman. My gratitude for all her hours of both friendship and
mentorship cannot be measured. I would also like to thank Dr. Scott Reaves whose
meticulous editing and suggestions helped tremendously in the culmination of my final
thesis product. Additionally, Dr. Reaves‟ human metabolism classes will remain one of
my favorite memories of my graduate school education. I would also like to thank Dr.
Ann McDermott who not only provided advice and guidance for my thesis project, but
also gave me the opportunity to work as a nutrition educator in the community. I learned
so much working under her direction and am very thankful for the experience.
I also could not be where I am today without the support of my mother, father,
sister, and grandparents. Their encouragement and belief in me allowed me to follow a
new career path when it wasn‟t the easy one to take. Finally, I would like to thank my
husband Greg who has remained endlessly supportive throughout my graduate studies
even when I spent more time at the computer than talking to him. His excitement about
my future as a professional is contagious and I am incredibly lucky to have him by my
side.
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TABLE OF CONTENTS
List of Tables .....................................................................................................................ix
List of Figures ....................................................................................................................xi
Chapter 1 .............................................................................................................................1
Introduction .............................................................................................................1
Definitions ...................................................................................................2
Chapter 2 .............................................................................................................................4
Review of Literature ...............................................................................................4
The Need for Prevention and Treatment of Overweight and Obesity ........4
Health Costs of Obesity ..................................................................5
Psychological Costs of Obesity ......................................................6
Financial Costs of Obesity ..............................................................7
Effect of Weight loss on Obesity Related Health Indicators ..........7
Behavioral Intervention Strategies ..............................................................8
History of Behavioral Weight Loss Interventions ..........................9
Behavioral Weight Loss Maintenance Interventions ....................13
Social Cognitive Theory and Health Promotion .......................................15
Growth of Internet-Based Behavioral Interventions .................................17
Online Weight Loss Interventions ............................................................20
Motivational Interviewing ............................................................31
Online Weight Loss Maintenance Interventions .......................................32
The Use of Theory in Behavioral Internet Interventions ..........................39
Behavioral Interventions and SCT Constructs in Online
Interventions .................................................................................40
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Utilization of Specific Constructs in Online Intervention Development ..44
Face-to-Face Orientation ..............................................................45
Organized Group Discussions .......................................................46
Self-Monitoring .............................................................................47
Tailoring and Feedback .................................................................49
Adherence, Logins, and Attrition ..................................................51
Social Support ...............................................................................56
Summary ...................................................................................................60
Chapter 3 ...........................................................................................................................62
Materials and Methods ..........................................................................................62
Formative Data ..........................................................................................62
Program Background ................................................................................64
Participants ................................................................................................64
Website Design .........................................................................................65
Questionnaire Development ......................................................................66
Intervention ...............................................................................................68
Data Coding and Collection ......................................................................72
Definition of New Variables .....................................................................72
Statistical Analysis ....................................................................................73
Chapter 4 ...........................................................................................................................75
Results ...................................................................................................................75
Baseline Characteristics ............................................................................75
Self-Efficacy .............................................................................................76
vii
Social Support ...........................................................................................79
Knowledge ................................................................................................82
Food, Eating and Coping Behaviors .........................................................82
Website Usage ..........................................................................................83
Website Perceived Usefulness ..................................................................85
Social Cognitive Theory Constructs from TCOC Comments ..................87
Social Cognitive Theory Constructs from Post-Intervention
Questionnaire .......................................................................................88
Chapter 5 ...........................................................................................................................90
Discussion and Conclusions .................................................................................90
Website Features and Use .........................................................................97
Conclusion Statement .............................................................................100
References .......................................................................................................................101
Appendices ......................................................................................................................108
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LIST OF TABLES
1. Table 1.1: Body Mass Index Classifications for Adults (CDC 2009) ………………........2
2. Table 2.2: Summary of Internet-Based Weight Loss and Weight Loss Maintenance
Interventions ...………………………………………………………………..................34
3. Table 2.3: Summary of Theory-Based Constructs Used in Internet Interventions ...........59
4. Table 3.1: Frequency of Weekly Updates Related to TCOC Sections ...………..............70
5. Table 4.1: Transformation Challenge Online Community Participant Demographics at
Baseline …………………………………………………………………………….........75
6. Table 4.2: Transformation Challenge Online Community Participant Education Level ..75
7. Table 4.3: Transformation Challenge Online Community Participant Previous Use of
Internet ……………………………………………………………………………..........76
8. Table 4.4: Comparison of Mean Scores Pre- and Post-Intervention and Paired-T Tests
for Self-Efficacy to Adopt and Maintain Healthy Behaviors as Reported from
Participants of the Transformation Challenge Online Community ………......................78
9. Table 4.5: Comparison of Mean Scores Pre- and Post-Intervention and Paired-T Tests
for Perceived Social Support as Reported from Participants of the Transformation
Challenge Online Community …………………………………………………..............80
10. Table 4.6: Social Support Reponses Pre- and Post-Intervention with Mean Difference
by Level of Website usage ……………………………………………………................81
11. Table 4.7: Mean Differences, Standard Deviation, and 95% Confidence Interval for
Knowledge of Dietary Guidelines for Americans as Reported from Participants of the
Transformation Challenge Online Community ……………………………………........82
12. Table 4.8: Comparison of Mean Scores Pre- and Post-Intervention and Paired-T Tests
for Food, Eating, and Coping Patterns as Reported from Participants of the
Transformation Challenge Online Community …………….......…………….................83
13. Table 4.9: Summary of Transformation Challenge Online Community Usage: Means,
Standard Deviations, and Ranges for Time Spent Online; Unique Number of Daily
Visits; and Number of Posted Comments ………………………….................................84
14. Table 4.10: Total Comments, Total Time spent online and level of website usage by
participant ID number ………………………………………………………...................85
ix
15. Table 4.11: Perceived Usefulness of Transformation Challenge Online Community
Sections as Rated by Participants Post-Intervention (n=12) …….....................................86
16. Table 4.12: Social Cognitive Theory Constructs Analyzed from Participant Posted
Comments on the Transformation Challenge Online Community ……………...............87
17. Table 4.13: Type and Number of Sources of Social Support as Reported on Post-
Intervention Questionnaires Based on Website usage ……………………………..........89
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Description:Table 4.4: Comparison of Mean Scores Pre- and Post-Intervention and Paired-T Tests The Use of Theory in Behavioral Internet Interventions
