Psychology of Eating
Neil RowlandUniversity of Florida
Emily Crews SplaneFlagler College
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ISBN-10: 0-205-85263-7ISBN-13: 978-0-205-85263-5
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Library of Congress Cataloging-in-Publication DataRowland, Neil. Psychology of eating/Neil Rowland, University of Florida, Emily Splane,
Flagler College.—First Edition. pages cm Includes bibliographical references. ISBN-13: 978-0-205-85263-5 (alk. paper) ISBN-10: 0-205-85263-7 (alk. paper) 1. Food habits—Psychological aspects. 2. Nutrition—Psychological aspects. 3. Nutrition policy.
I. Splane, Emily. II. Title. TX357.R795 2013 394.1'2—dc23 2013018169
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BrIEF COnTEnTS
Chapter 1 Psychology of Eating: The Nexus of Nutrition, Brain, and Behavior 1
Chapter 2 Macronutrients and the Food We Eat 12
Chapter 3 The Chemical Senses 27
Chapter 4 You are What You Eat: Evolution, Energy, and Foraging 45
Chapter 5 Basic Learning Processes and Eating Behavior 60
Chapter 6 The Development of Eating Behaviors 76
Chapter 7 Social Influences on Eating 96
Chapter 8 Mood and Food, Cravings, and Addiction 107
Chapter 9 Hunger, Satiety, and the Brain 122
Chapter 10 Eating Disorders and Treatment 138
Chapter 11 Genes, Epigenetics, and Obesity 155
Chapter 12 Treatments for Obesity 168
Chapter 13 Where Do We Go from Here? 180
iii
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Diet-Induced Thermogenesis (DIT) 24Let’s review and apply your knowledge. Take some time to answer these chapter questions 24 • Do the math energy calculation 24 • Glossary 24 • References 26
Chapter 3 The Chemical Senses 27Olfaction: The Sense of Smell 28
Odorants and Receptors 28▶ Talking Point 3.1 28
Projections to the Brain 30■ BOX 3.1: Do You Smell What I Smell or
Your Dog Smells? 31
Anosmia 31▶ Talking Point 3.2 32
Gustation: The Sense of Taste 32
GPCR Taste Receptors: Sweet, Umami, and Bitter 33■ BOX 3.2: Taste Bud Turnover 34
Ionotropic Taste Receptors: Salty and Sour 34
Other Tastes 34▶ Talking Point 3.3 35
Taste Coding in Higher Brain Regions 35
Flavor 35■ BOX 3.3: So You Think You Can
Taste? 36
Taste- or Flavor-Guided Behaviors 36
Stimulus Presentation 36
Innate or Learned 36▶ Talking Point 3.4 37
Palatability 37
Chemical Sensing and the Enteric Nervous System 38
▶ Talking Point 3.5 39
COnTEnTS
Preface xi
Chapter 1 Psychology of Eating: The Nexus of Nutrition, Brain, and Behavior 1Introduction 1
What Is the Goal of Eating? 3▶ Talking Point 1.1 4▶ Talking Point 1.2 6
What Is the Definition of Obesity? 6▶ Do the Math 7
Biomedical or Environmental or Both? 9Do the math BMI calculation 10 • Glossary 10 • References 11
Chapter 2 Macronutrients and the Food We Eat 12Macronutrient Classes 12
Carbohydrates 14▶ Talking Point 2.1 14
Proteins 15▶ Talking Point 2.2 16
Fats 17
Nutrition Facts and Food Labels 18▶ Talking Point 2.3 18
▶ Do the Math 19
Micronutrients 19
Salts 19
Sodium and Sodium Appetite 20▶ Talking Point 2.4 21
Vitamins 21
Energy Balance 21
Energy Input 21
Energy Output 22
Basal Metabolic Rate (BMR) 23
Activity: Metabolic Cost of Exercise 23▶ Talking Point 2.5 23
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vi Contents
Taste and Food Aversions 62
Learning of Food by Experience: Increasing Preferences 63
Medicine Effect 63
Mere Exposure 64■ BOX 5.1: Do Food Preferences of Babies
Increase with Exposures? 65
Flavor-Flavor Associative Learning 65▶ Talking Point 5.1 66
Flavor-Nutrient Associative Learning 66■ BOX 5.2: Can Flavor-Flavor Learning
Happen Easily? 66■ BOX 5.3: Do Animals Learn Associations
Between Flavors and Nutrients? 67
▶ Talking Point 5.2 68
Learning of Appropriate Food Quantity: Conditioned Satiety 68
■ BOX 5.4: How Do Rats Know When It’s Mealtime? 69
Learning of When to Eat: Conditioned Hunger 69
■ BOX 5.5: Do Food Cues Trigger Eating Even in Absence of Hunger? 69
Influence of Learned Contextual Cues 70▶ Talking Point 5.3 71
Conditioned Immune System Activity 71
Neurobiology of Food Learning 71Let’s review and apply your knowledge. Take some time to answer these chapter questions 73 • Glossary 73 • References 74
Chapter 6 The Development of Eating Behaviors 76The Ontogeny of Human Feeding: Prenatal Experience 76
■ BOX 6.1: What’s the Evidence? 71■ BOX 6.2: Can Babies Taste and Smell
Before Birth? 79
Gut Hormones That Affect Food Intake 39
■ BOX 3.4: What's the Evidence That CCK Is an Anorectic Agent 39
Insulin 40■ BOX 3.5: Diabetes 40
Let’s review and apply your knowledge. Take time to answer these chapter questions 41 • Glossary 41 • References 43
Chapter 4 You are What You Eat: Evolution, Energy, and Foraging 45Ancestors and Evolution 45
▶ Talking Point 4.1 47
Energy 48▶ Talking Point 4.2 48
Optimal Foraging 49▶ Do the Math 50▶ Talking Point 4.3 51
Economics of Food 51
Unit Price and Access Cost 52
Meal-Defining Criteria 53▶ Talking Point 4.4 53▶ Talking Point 4.5 54
Portion Size 54
Economics and humans 56▶ Talking Point 4.6 56▶ Talking Point 4.7 57
Concluding Remarks 58Let’s review and apply your knowledge. Take some time to answer these chapter questions 58 • Answers to Do the Math 58 • Glossary 58 • References 59
Chapter 5 Basic Learning Processes and Eating Behavior 60Overview of Classical Conditioning and Terminology 60
Learning of Post-Ingestive Consequences: Taste Aversions and Preferences 62
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Contents vii
Direct Influences of Others 102▶ Talking Point 7.3 103
Why Do We Eat Previously Disliked Foods? 103
Food Associations with the Provider 104■ BOX 7.1: Are We Neurologically Affected
By Labels? 104
Concluding Remarks 105Glossary 105 • References 105
Chapter 8 Mood and Food, Cravings, and Addiction 107The Mood-Food Connection 107
▶ Talking Point 8.1 108
A Biological Explanation for Carbohydrate (Sugar) Craving? 108
Stress and Eating 109▶ Talking Point 8.2 109▶ Talking Point 8.3 110
Food Cravings 110▶ Talking Point 8.4 111
Is Chocolate Special? 111
Psychological and Sociocultural Explanations for Chocolate Craving 112▶ Talking Point 8.5 113
Can Someone Actually be a “Food Addict”? 113▶ Talking Point 8.6 114
Neurobiology of Food Addiction 115■ BOX 8.1: Does Weight Affect Brain
Reactivity to Food Cues? 117
Concluding Remarks 118Let’s review and apply your knowledge. Take some time to answer these chapter questions 119 • Glossary 119 • References 120
Chapter 9 Hunger, Satiety, and the Brain 122Central Origin of Hunger 122
Allostasis 123
Early Postnatal Eating: From Suckling to Eating Solid Foods 79
Breast versus Bottle (Formula) Feeding 80■ BOX 6.3: Does Exposure Affect Intake 81
Adding Solid Foods to the Diet 82
Not Needing a Bottle, but Still Needing Guidance: Eating in Early Childhood 83
Can Infants and Young Children Self-Regulate Energy Needs? 83
Experimental Studies of Caloric Regulation 84▶ Talking Point 6.1 85■ BOX 6.4: Do Children Recognize
Calories? 85▶ Talking Point 6.2 86
External Influences on Children’s Eating: Disruptions in Energy Self-Regulation 86
Parenting Styles, Attitudes, and Weights 86▶ Talking Point 6.3 87
Social Influences 88
Food Availability and Portion Sizes 89
Media 89▶ Talking Point 6.4 90
Implications for Instilling Healthy Eating Habits in Children 90
▶ Talking Point 6.5 91Let’s review and apply your knowledge. Take some time to answer these chapter questions 92 • Glossary 92 • References 92
Chapter 7 Social Influences on Eating 96Cuisine 96
Determinants of Cuisine 98▶ Talking Point 7.1 99▶ Talking Point 7.2 101
Direct versus Indirect Influences 101
Indirect Influences 101
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Biopsychosocial Explanations of Eating Disorders 144
Biological Factors 145▶ Talking Point 10.1 145
Psychological Factors 146
Sociocultural Factors 147
Treatments 147
Is Treatment Effective? 148
Animal Models of Anorexia and Bulimia 149
Concluding Remarks 150Let’s review and apply your knowledge. Take some time to answer these chapter questions 151 • Glossary 151 • References 151
Chapter 11 Genes, Epigenetics, and Obesity 155Monogenic Obesity 156
■ BOX 11.1: What’s the Evidence? Mutant Mice and the Lipostatic Hypothesis 158
Polygenic Obesity 159▶ Do the Math: Genes and Obesity 159■ BOX 11.2: Gene Therapy 162
Epigenetics and Developmental Programming 162
Dietary Obesity 163▶ Talking Point 11.1 164Answers to Do the Math 166 • Let’s review and apply your knowledge. Take some time to answer these chapter questions 166 • Glossary 166 • References 167
Chapter 12 Treatments for Obesity 168Anti-Obesity Drugs 168
Drugs That Reduce Energy Intake 168
■ BOX 9.1: What’s the Evidence? Origins of Hunger or Satiation 123
▶ Talking Point 9.1 125
Hypothalamus, Transmitters, and Feeding 125
■ BOX 9.2: What’s the Evidence? Spotlight on Npy and Agrp as a Feeding Peptides 127
Meals 127▶ Talking Point 9.2 128■ BOX 9.3: Food for Thought: This is (or was)
Your Brain on Fat! 129▶ Talking Point 9.3 129
Estrogens 130▶ Talking Point 9.4 130
Reward and Decision Making 131■ BOX 9.4: What’s the Evidence? The
Mesolimbic System is Activated by Food 132
■ BOX 9.5: What’s the Evidence? Interaction of Reward Systems and Energy Regulation 133
▶ Talking Point 9.5 133Let’s review and apply your knowledge. Take some time to answer these chapter questions 134 • Glossary 134 • References 135
Chapter 10 Eating Disorders and Treatment 138Anorexia Nervosa 139
Katie 139BOX 10.1 How Can Body Perception Be
Measured? 140
Medical Problems Associated with AN 141
Bulimia Nervosa 142
Medical Problems Associated with BN 142
Andrea 143
Risk Factors for Eating Disorders 143
viii Contents
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Chapter 13 Where Do We Go from Here? 180Obesity, the Disease 180
▶ Talking Point 13.1 181
Exercise, the Cure (?) 182▶ Do the Math 183▶ Talking Point 13.2 184
Roles for Government and/or Industry 184
▶ Talking Point 13.3 187
Eating In, Eating Out, and Eating All About 188
▶ Talking Point 13.4 189
To the Future 189Answers to problems in Do the Math 189 • Glossary 190 • References 190
Appendix 1 Overview of Neurons and Brain Architecture 191
Appendix 2 Genetics 196
Credits 201
Index 202
Drugs and Supplements That Increase Energy Expenditure 170
Calorie Substitutes 171▶ Talking Point 12.1 171
Surgery for Obesity (Bariatric Surgery) 172
Types of Surgery 172
Physiological Effects of Surgery 173
Factors to Consider Regarding Surgery 173
Adolescents and Surgery 174
Cost of Surgery 174■ BOX 12.1: A Celebrity’s Experience with
Weight and Surgery 174
Weight Regain After Surgery 175
Diet, Exercise, and Behavioral Therapy 175
Concluding Remarks 176Let’s review and apply your knowledge. Take some time to answer these chapter questions 177 • Glossary 177 • References 177
Contents ix
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classified as overweight or obese, this field will provide considerable employment opportuni-ties for the foreseeable future! Our book might also serve as background material from which to launch discussions at a graduate level. Most of our chapters include citations to primary or addi-tional resources.
Most human behaviors, and misbehav-iors, have biological and sociocultural deter-minants. Eating is an excellent example of this, and in addition uses commodities (foods) that themselves have defined physical and chemi-cal properties. So you cannot understand eating without knowing something about nutrition, energy, genes, chemical sensing, and brain struc-tures. This book contains information about all of these, and it would have been easy to write an entire book on these topics. Instead, we have tried to present these topics in a relatively simple form within the context of the science background typical of many psychology majors. That is, you don’t have to be an expert in all or any of these areas to be able to read and hope-fully understand the book. We believe that even if your primary interest is in the sociocultural topics, taking the time to read about biological foundations will enrich your understanding. Conversely, we do not believe that exclusive focus on the basic science aspects enables you to appreciate the complexity of human thought and behavior that dominates most people’s deci-sions about what, when, and how much they eat. The book is not organized in a rigidly linear or progressive manner: Each chapter stands alone and can be sequenced in more or less any order, but this order works for us! In the last chapter of the book, which you probably should leave for last, we discuss treatments or strategies to reverse this trend toward an obese world—a trend that is economically unsustainable. It’s convenient to point the finger of blame at the food industry, and some entities have done just that by imple-menting controversial taxes or other restrictions.
PrEFACE
People are obsessed with food. If you do not have enough food, which was almost always the case for our distant ancestors, your thoughts and actions are directed toward obtaining food. Even in today’s world in which many of us have plenty of “mouth-ready” food available, people spend large amounts of time thinking about food or rituals in which food plays a prominent role. Huge for-profit industries have been built on these human proclivities, ranging from advertis-ing, production or retailing of an increasing array of tasty foods, to weight management or loss and medical treatment of obesity-related diseases.
Have you ever stopped to ask why humans are so attracted to food, or whether it is unique to humans? This book attempts to pose these ques-tions, and explore answers. We firmly believe that psychological science is the only academic disci-pline that is capable of spanning and integrating the vast range of subdisciplines that are relevant to the topic. In this text, we focus on “normal” eat-ing: How did it evolve, how does it develop and become manifest in modern society, and what functions does it fulfill? We also address contem-porary problems associated with eating. We have a chapter devoted to diagnosable eating disorders including anorexia and bulimia nervosa; however, from a perspective of sheer numbers and adverse economic impact, eating too much and becoming obese is by far the biggest problem. Thus, much of the book is focused on explanations of and pos-sible solutions to what many in the field now refer to as an obesity epidemic.
This book has arisen out of an undergradu-ate special topics course “Psychology of Eating” we first taught about a decade ago. Our impetus was to develop an integrative or capstone course for undergraduates who simply want to learn more about their own eating, who are contem-plating a career in one of the for-profit industries mentioned earlier, or in a related government or nonprofit activity. With more than 50% of the adult population and up to 25% of children now
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xii Preface
this project. We also thank the reviewers of earlier drafts of these chapters for their insightful com-ments that have improved every aspect of the book: Charlotte Markey, Rutgers University; Jennifer Harriger, Pepperdine University; Deb Briihl, Valdosta State University; Sarah Savoy; Alison Ventura, Drexel University; Doris Davis; Thomas Alley, Clemson University; Steven St. John, Rollins College; Lori Forzano, The College at Brockport, State University of New York; Bryan Raudenbush, Wheeling Jesuit University; Kevin Myers, Bucknell University and Carla Bluhm, College of Coastal Georgia, and especially all of our students who are our enduring inspiration.
But we regard the real problem as the love affair that people have with food and its manifestations such as marketing. What strategies have the best chance to cool off this affair and implement sus-tainable lifelong relationships with food?
The “obesity problem” is not fundamentally different from other contemporary issues, for example, climate change. In both cases, technolo-gies have over time enabled humans to develop unsustainable behaviors: We have to find techno-logical and psychological approaches to change those behaviors.
We want to thank the editors and staff at Pearson for encouragement and help throughout
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