The Creation and Testing of a Scale to Measure the Subjective Experiences of Hunger and Satiety a DISSERTATION SUBMITTED TO
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The Creation and Testing of a Scale to Measure the Subjective Experiences of Hunger and Satiety A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Melinda B. Karalus IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Dr. Zata Vickers July 2011 © Melinda B. Karalus 2011 ACKNOWLEDGEMENTS To my advisor, Zata Vickers, I am grateful for the guidance she provided me during my graduate studies, and for the education she gave me throughout my research planning, implementation and analysis. I would also like to thank Joanne Slavin, David Weiss, Tonya Schoenfuss, and Devin Peterson for their advice on my research and for serving on my examining committee. A special thanks to William Thomas for his statistical advice throughout each of my scale validation studies and to Kathy Greaves who provided funding, planning and insight into the fiber study. I would also like to thank Michelle Diedrick for all of her initial planning work towards the fiber study. I wish to acknowledge General Mills Inc. for supporting my focus group research and the Kellogg Company for supporting my fiber study research. Many thanks to the sensory panelists who participated in my studies and to the other graduate students in Zata‘s lab for their help, advice and support throughout my time at the University of Minnesota. Thanks to Emeline Brouard, Elizabeth Farniok and Jamie Bachaus who helped with the execution of the scale validation studies. Finally, I am grateful for my family and especially my husband, Brennan Karalus, for being supportive of me throughout the entire graduate school process. A special thanks to my mother, Carol Robacker, who provided great insights and understanding of the PhD process. She always patiently listened to my research ideas – I consider her my honorary advisor. Without the support of my family, I would not be who and where I am today. Thanks! i ABSTRACT Satiety, in this dissertation, broadly refers to the feeling of fullness and/or inhibition of hunger sensations after a meal resulting from the ingestion of food. The objective of the experiment in Chapter 2 was to gain a better understanding of hunger and fullness from consumers through the use of focus groups. Hunger and fullness sensations were described as having both physical and psychological components. The objectives of Chapter 3 and 4 were to develop and test a questionnaire to assess satiety sensations. Factor analysis of satiety related questions revealed five factors: mental hunger, physical hunger, mental fullness, physical fullness and food liking. These five factors have been named the Five Factor Satiety Questionnaire. In the first validation study, thirty participants evaluated satiety feelings produced by oranges and oatmeal. Food intake from an ad libitum snack offered two hours after breakfast was covertly recorded. The factor scales and traditional single-item scales (hunger, fullness, desire, and prospective consumption) revealed that oatmeal was more satiating than oranges. The factor scales offered enhanced understanding over the traditional scales by showing that oranges produced much more mental hunger and slightly more physical hunger than the oatmeal. The factor scales also had smaller distributions around the means and greater effect sizes than the traditional scales. In a second study, participants evaluated satiety feelings produced by two equal-calorie smoothies that differed only in that one contained cumin to lower acceptability. The more palatable regular smoothie provided greater mental fullness factor sensations than the spiced cumin smoothie. Again, all of the factor scales produced smaller distributions around the means and greater effect sizes. The experiment in Chapter 5 was conducted in response to the interest in understanding satiety that added fibers provide. Hunger and satiety of 10g of oligofructose, inulin, soluble corn fiber, resistant wheat starch and a control with no added fiber in chocolate crisp bars was evaluated. Satiety ratings were made using three satiety scale protocols: (1) Slavin scales of hunger, fullness, satisfaction and prospective consumption, (2) traditional scales of fullness, hunger, amount, and desire and (3) factor scales of mental hunger, physical hunger, mental fullness, physical fullness and food liking. Food intake was measured at ii an ad libitum lunch served 180min after breakfast and subjects recorded food intake over the remainder of the 24hr study day. Breath hydrogen, breath methane and GI tolerance were assessed. While there were no significant differences in hunger or satiety found using the Slavin scales, traditional scales or factor scales among the fiber treatment bars during the three hour study duration, the factor scales exhibited the least amount of variability indicating higher sensitivity to the differences between the bars than the Slavin or traditional scales. There was also no significant difference found in the ad libitum lunch or 24hr calorie consumption among the different fibers. The bar with oligofructose produced the greatest amount of breath hydrogen, bloating and flatulence ratings while the control bar produced the least. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS .............................................................................................. i ABSTRACT ....................................................................................................................... ii TABLE OF CONTENTS ................................................................................................ iv LIST OF TABLES ........................................................................................................... vi LIST OF FIGURES .......................................................................................................... x Chapter 1 ........................................................................................................................... 1 Introduction ....................................................................................................................1 Satiety Defined...............................................................................................................2 Common Satiety Descriptors .........................................................................................5 Current Methods to Measure Satiety .............................................................................9 Line Scales .........................................................................................................9 Pictorial Methods.............................................................................................13 Food intake ......................................................................................................14 Combination of food intake and line scale ratings ..........................................17 Length of satiety studies ...................................................................................18 The Effectiveness of Current Satiety Screening Methods ...........................................18 Influence of food liking on satiety ....................................................................20 Participant Differences – Influences on Satiety Ratings ..............................................21 Gender and Age ...............................................................................................21 Eating restraint ................................................................................................22 Body Mass Index (BMI) ...................................................................................25 Satiety of Foods ...........................................................................................................26 Fiber .................................................................................................................27 Fat. ..................................................................................................................28 Carbohydrate ...................................................................................................29 Protein..............................................................................................................30 Food Form .......................................................................................................31 RESEARCH OBJECTIVES AND HYPOTHESES .................................................... 34 Chapter 2 ......................................................................................................................... 40 CONSUMER VIEWS OF HUNGER AND FULLNESS: A QUALITATIVE APPROACH .................40 Introduction ......................................................................................................41 Methods............................................................................................................45 Results ..............................................................................................................49 Discussion ........................................................................................................59 Chapter 3 ......................................................................................................................... 66 THE DEVELOPMENT OF A SCALE TO MEASURE THE SUBJECTIVE EXPERIENCES OF HUNGER AND SATIETY ..............................................................................................66 iv Introduction ......................................................................................................66