psychology of eating - pearson education · brief contents chapter 1 psychology of eating: the...

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

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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


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


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


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


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


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


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


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


Chapter 13 Where Do We Go from Here? 180Obesity, the Disease 180


Exercise, the Cure (?) 182▶ Do the Math 183▶ Talking Point 13.2 184

Roles for Government and/or Industry 184


Eating In, Eating Out, and Eating All About 188


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


Contents ix


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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