Clemson University TigerPrints All Dissertations Dissertations 5-2012 Sources of Variance in Bite Count Jenna Scisco Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Part of the Psychology Commons Recommended Citation Scisco, Jenna, "Sources of Variance in Bite Count" (2012). All Dissertations. 914. https://tigerprints.clemson.edu/all_dissertations/914 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. SOURCES OF VARIANCE IN BITE COUNT A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Human Factors Psychology by Jenna Lori Scisco May 2012 Accepted by: Dr. Eric R. Muth, Committee Chair Dr. Thomas R. Alley Dr. Adam W. Hoover Dr. Patrick J. Rosopa ABSTRACT The obesity epidemic affects millions of individuals worldwide. New tools that simplify efforts to self-monitor energy intake may enable successful weight loss and weight maintenance. The purpose of this study was to examine predictors of the number of bites recorded by the bite counter device during daily meals in natural, real world settings. Participants (N = 83) used bite counters to record daily meals for two weeks. Participants also recorded their daily dietary intake using automated, computer-based 24- hour recalls. Predictors of bite count were explored at the meal-level and individual-level using multilevel linear modeling. A positive relationship between kilocalories and bites was moderated by energy density such that participants took more bites to consume greater kilocalorie meals when energy density was low than when energy density was high. The positive relationship between kilocalories and bites was also moderated by participants’ average bite size during a laboratory meal such that participants with smaller bite sizes took more bites to consume greater kilocalorie meals than participants with larger bites sizes. Participants also took more bites when they ate meals with others and when they ate meals outside of the home, although this meal location effect was not reliably produced across models. Practical implications of these results for future bite counter development and research are discussed. ii DEDICATION I dedicate this dissertation to my husband, Gary Giumetti. His love and endless support kept me moving forward during the most difficult stages of my PhD journey. I also dedicate this dissertation to my family. My parents, Peter Scisco and Lori Scisco, provided me with constant love and encouragement throughout my 20+ years of formal education. Thank you for teaching me that I could do anything I put my mind to, and for always being there for me. I would also like to congratulate and thank my sister, Dr. Leigh Scisco, DPT, for sharing the journey to “doctor” with me. iii ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Eric Muth, for his outstanding guidance, support, training, and advice during my graduate school career. Thank you for encouraging me to grow intellectually throughout this dissertation process. I would also like to thank Drs. Adam Hoover, Patrick Rosopa, and Tom Alley for their guidance on this dissertation. I would like to thank the SMART Scholarship program for providing funding for the two years during which I completed this dissertation. I would like to thank all of my friends for their support here at Clemson and long distance via phone and e-mail. Special thanks go to Dr. Stephanie Fishel-Brown for providing feedback on manuscript drafts and never-ending encouragement. iv TABLE OF CONTENTS Page TITLE PAGE .................................................................................................................... i ABSTRACT ..................................................................................................................... ii DEDICATION ................................................................................................................ iii ACKNOWLEDGMENTS .............................................................................................. iv LIST OF TABLES ......................................................................................................... vii LIST OF FIGURES ......................................................................................................... x CHAPTER I. INTRODUCTION ......................................................................................... 1 Purpose ..................................................................................................... 1 Obesity ..................................................................................................... 1 Self-Monitoring...................................................................................... 10 The Bite Counter .................................................................................... 20 Multilevel Linear Modeling of Eating Behavior ................................... 27 The Present Bite Counter Study ............................................................. 45 II. METHODS .................................................................................................. 59 Participants ............................................................................................. 59 Materials ................................................................................................ 66 Procedure ............................................................................................... 76 Statistical Analyses ................................................................................ 81 III. RESULTS .................................................................................................... 92 Original Data .......................................................................................... 92 MLM Analysis ....................................................................................... 92 Additional Two-Level Model .............................................................. 121 Additional Model with Outlier Participants Removed ........................ 126 Bite Size Model.................................................................................... 141 Lab Meal .............................................................................................. 148 v Table of Contents (Continued) Body Measurements............................................................................. 152 Usability Questionnaire ....................................................................... 153 IV. DISCUSSION ............................................................................................ 160 Sources of Variance in Bite Count ....................................................... 160 Lab Meal .............................................................................................. 177 Weight Loss ......................................................................................... 178 Implications of ASA24 and Bite Counter Usability ............................ 180 Study Strengths .................................................................................... 183 Study Limitations ................................................................................. 186 Future Research Directions .................................................................. 188 The Future Bite Counter ...................................................................... 191 Conclusion ........................................................................................... 192 APPENDICES ............................................................................................................. 194 A: Demographics Questionnaire ..................................................................... 195 B: Three-Factor Eating Questionnaire R-18 (TFEQ R-18) ............................ 200 C: Daily Meals Questionnaire ........................................................................ 202 D: Usability Questionnaire ............................................................................. 208 E: Initial Participant Contact and Online Prescreening Protocol ................... 214 F: Orientation Protocol ................................................................................... 218 G: Written Consent Form................................................................................ 222 H: Bite Counter Instructions ........................................................................... 224 I: ASA24 Dietary Recall and Daily Meals Survey Instructions .................... 226 J: Appointment Slip ....................................................................................... 227 K: Data Download Meeting Protocol ............................................................. 228 L: Final Meeting and Meal Protocol .............................................................. 230 M: Satiety Labeled Intensity Magnitude (SLIM) Scale .................................. 235 N: Labeled Affective Magnitude (LAM) Scale .............................................. 236 O: Data Merging and Error Screening Steps .................................................. 237 P: Description of Data Quality for Each Participant ...................................... 241 REFERENCES ...........................................................................................................