Thinking in Circles About Obesity (eBook)

Dr. Tarek K.A. Hamid is a trained system dynamicist (with a PhD from MIT, and a winner of the Forrester award for his first book). He has been a Professor of System Dynamics at the Naval Postgraduate School, in Monterey, CA since 1986, where he was awarded the Naval Postgraduate School's Faculty Performance Award, in recognition of meritorious faculty performance in both research and teaching. In the mid 1990s he became extremely interested in the confluence of information and medical technologies, and saw it as one of the most promising new frontiers for system dynamics research and public policy. But he had a lot for me to learn. So, in 1997, he took an open-ended leave-of-absence and enrolled in the Master's Program at Stanford's Engineering Economic Systems & OR Dept., where he focused on decision analysis and medical decision-making. (Returning to become a master student, while already holding a PhD was certainly a "weird" experience—for him, and for his professors—but it was a lot of fun.) It was during his studies at Stanford that he began to see the natural fit between the obesity problem (as a dynamic system of energy regulation) and system dynamics. (Research was revealing that human bioenergetics belongs to the class of multi-loop nonlinear feedback systems—the same class of system that system dynamics aims to study.) Upon graduation, he spent a year (1999-2000) as an affiliate at Stanford’s Medical Informatics Department (part of Stanford’s Medical School), where he worked on developing system dynamics models of human physiology and metabolism. In December 2001, he returned to his faculty position at the Naval Postgraduate School where he continues his research on medical decision making and modeling of human metabolism and energy regulation. When not teaching or writing, Tarek is usually on the water. With his wife, Nadia, won first place in the 1999 San Francisco to Santa Barbara Yacht Race (Cruise Division) on their traditional Alden 45 sloop.

Preface 6
The Book’s Outline 7
The Story of the Book 8
Acknowledgments 9
Contents 11
Part 1: Mismanaging the Obesity Threat 17
Like Boiled Frogs 18
How the Problem Sneaked Up on Us 18
The Temperature Is Rising 20
The Heavy Burden of Obesity 22
For Older Americans, The Future Is Now 24
The Sociocultural Burden 25
‘‘Globesity’’ 26
A Bucket Half-Empty? 27
The Leverage (or the Impediment) Is with the People 28
It Is Not Easy Becoming a Top Gun 29
States In Mind 31
Emotions Play a Role 35
Failure to Learn from Failure 37
Single-Loop vs. Double-Loop Learning 37
Barriers to Learning 42
What Is to Be Done? 43
Metanoia 43
Synthesis, Not Analysis 43
What Is Feedback? 47
Circles, Not Straight Lines 47
Dynamic, Not Static 51
Obliterating, Not Automating 53
Notes 55
Part 2: How We Changed Our Environment, and Now Our Environment Is Changing Us 65
Unbalanced Act 66
‘‘For every complex problem there is an [explanation] that is simple, direct, and hellip wrong.’’ 67
Moving Beyond Individual-Centric Explanations 69
‘‘Civilization is but a filmy fringe on the history of man.’’ 69
Evolved Asymmetry of Our Physiology 72
How Asymmetry Is Achieved by Our Physiology 73
Asymmetry in Energy Intake 73
Asymmetry in Energy Expenditure 77
Asymmetry in Energy Storage 78
Conclusion 80
Human-Environment Interactions: Not One Way hellip and Not One-Way 81
Human Behavior Is Not Expressed in a Vacuum 83
It Is Not Just Physical 84
We shape our environment, and then our environment shapes us. 86
A Symphony Out of Tune? 87
Tilting the Energy Balance: More Energy In 88
The Quantity of Food We Eat 89
The Causes Behind the Cause 91
How America’s Eating Habits Started to Change 91
The First Mechanism: The Time We Eat 97
Soft Drinks: The Liquid Snack 99
The Second Mechanism: Where We Eat 101
Fast Food: Eat Anywhere, Everywhere 102
The Qualitative Dimension 103
The Quantity Dimension 106
Events Give Birth to Trends, But What Escalates Them Are Self-Reinforcing Processes 111
Demand-Pull 114
Supply-Push 116
Putting It All Together 119
Hurricane Obesa 120
Tilting the Energy Balance: Less Energy Out 121
The Water Is Boiling! 121
Work: Engineering Energy Expenditure Out of the Workplace 123
Moving About: Transport and Urban Design 125
Play and Leisure 128
The Burden Is Cumulative 130
Dr. Jekyll and Mr. Hyde, or Changing the Vicious to Virtuous 131
Individual Differences 134
Some Are ‘‘Squares,’’ and Some Are Not 134
Deciphering the Code, One Gene at a Time 135
Genes and Individual Susceptibility to Weight Gain: The Experimental Findings 137
The Pimas 139
Genetic x Environmental Interactions: Conclusion 141
Is Ad-Lib Behavior Killing Us? 143
A (Mis-)Match Made in America 143
Like Our Genes, Our Mental Models Did Not Change 145
Turning-Off Automatic Control and Asserting Cognitive Control 146
It Can Be Done 148
The Allure of the ‘‘Silver Bullet’’ 150
Looking Ahead 152
Notes 153
Part 3: We Can’t Manage What We Don’t Understand 175
The Energy Balance Equation: Reigning Intellectual Paradigm or Straitjacket? 176
The Magic Number 177
From the Experts’ Mouths to the Journalists’ Ears to the Public’s Mind 178
We Like to Believe that We Are in Full Control 180
What We Know that Ain’t So 182
Looking Back Versus Looking Forward 182
The First Trap: Linear Thinking 184
A Plumbing Analogy 187
A Second Trap: Energy as a Single Currency 189
We Need a Better ‘‘Map’’ 191
Closing the Loops on Energy Balance: Energy Output Side 192
Tip of a Physiological Iceberg! 192
‘‘Under-the-Surface’’ Determinants of Energy Expenditure 193
The System in Action: ‘‘Under the Surface’’ Responses to Energy Imbalance 198
Implications for Treatment 200
Failure to Account for Individual Differences 200
How an Energy Deficit Is Induced Also Matters 202
Seeing Through the Complexity 203
Revisiting the Bathtub Analogy 204
Learning to ‘‘Squint’’ 206
Closing the Loops on Energy Balance: Energy Input Side 209
Body Defenses on the Second Energy Front 209
Two-Tier System: Short-Term and Long-Term 210
Short-Term Component 211
Long-Term Component 212
Two Asymmetries, Not One 214
A Homeostatic System with a Difference 216
Beyond Physiology: Closing the Behavior-Physiology Loop 220
Not Only Do We Eat Food, We Also Think About It 220
Which Requires More Effort: To Do or Not to Do? 221
Strength (and Weakness) Model of Human Self-Regulation 222
A First Course in Managing Stocks and Flows 224
The Evidence: To Use It Is to Lose It, at Least Temporarily 226
A Challenge for the Self: How to Accomplish a Lot with a Little 227
Why Goals Matter, and How More May Be Less 229
Weight Cycling: Not Once, Not Twice 235
Understanding How Cycles Happen 236
Longer-Term Risks 240
Less Is More 241
Looking Back and Looking Forward 243
Looking Back 243
Understanding Is a First Step, But Far from Sufficient 244
Looking Forward 247
Notes 249
Part 4: We Can’t Manage What We Mis-Predict 266
Learning by Doing 267
How Hard Can It Be? 268
Trying Your Hand at Predicting Dynamics 269
The Bathtub Exercise 270
The Answer 272
What Do These Results Tell Us? 273
Beyond Bathtubs 276
‘‘Give Us the Tools, and We Will Finish the Job’’ 278
Sources of Complexity in Systems 278
The KISS Acronym: ‘‘Keep It Simple, Stupid’’ 280
Argument for a Calculus 282
Leveraging Computer Technology 283
A Microworld for Weight and Energy Regulation 284
Telescopes for the Mind 284
Simulation Models Are Operational Models 285
Overview of Model Structure 288
Energy Intake (EI) Subsystem 290
Energy Expenditure (EE) Subsystem 291
Energy Metabolism and Regulation Subsystem 292
Glucose and Free Fatty Acid Metabolism 293
Protein/Amino Acid Metabolism 297
Exercise Metabolism 298
Body Composition Subsystem 299
Fat Mass (FM) 300
Fat-Free Mass (FFM) 302
Taking Off 302
Experiment 1: Assessing Weight Loss-Reality Versus Fiction 304
The Experiment 306
Experimental Results 307
Looking Inside a White Box 309
It Is Not Academic 311
Experiment 2: Going Ballistic-On a Diet 312
Chasing a Moving Target 312
The Experiment 313
It Is No Passive Tool 315
Experiment 3: Understanding Why 250 Pounds Does Not Equal 250 Pounds 317
Individual Differences: More than Meets the Eye 317
The Experiment 318
Phase 1: Overfeeding 318
Phase 2: Dieting 320
One Size Does Not Fit All 322
Experiment 4: Trading Treatment Options-Diet Versus Exercise 324
Energy Is Not a Single Currency 324
Diet Versus Exercise: Do 500 kcal = 500 kcal? 325
Trading Exercise Intensity for Exercising Time 329
Manipulating Diet Composition 331
Don’t Trade hellip Integrate 333
PhDs for the Masses? (That’s Personal Health Decision support) 334
Notes 336
Part 5: Prevention and Beyond 349
The Fat Lady hellip Models 350
The Third Path: Prevention 354
Can’t Unscramble an Egg 354
The Buck Starts Here 355
Make Healthy Choices the Easy Choices 358
Public Works to Level the Playing Field 359
Energy Input 360
‘‘Thought for Food’’ 361
Economic Incentives 362
Energy Output 364
Often Preventable But Rarely Prevented 366
Location, Location, Location: Places to Intervene in Systems 368
Behavior Change Cannot Be Legislated 368
Lessons from Managing America’s Other Energy Problem 369
Leverage Points 374
Leveraging Paradigms hellip and Succeeding 376
Back in the United States: A Challenge and an Opportunity 380
It Will Take More Than Food Pyramids 383
‘‘Educate Them and They Will Change’’ 383
Half a Century of Government Education 383
It Is Not Working 385
It Is Deeper Than Just That 387
Information Is Not Enough to Change Mental Models 389
Learning from Experience: A Bad Second Option 394
Lessons from Business: Learning About Risky Stuff Without Experiencing the Risk 396
Transforming Prevention from a Spectator Sport to a Contact Sport 400
‘‘Virtual to Your Health’’ 404
Microworlds YAcy Us 405
Child’s Play 407
Learning About Healthy Behavior by Playing, Not by Lecturing 408
Double-Loop Playing 410
(Almost) Never Too Young to Think Systematically 410
At Home, the Real Risk Is in Expecting Too Little 413
Shifting the Burden and Its Risks 414
Keeping the Burden 417
Teaching Children to Fish 418
Balance of Powers and Responsibilities 420
Beyond Prevention 421
Wellness Does Not Mean Only a Lack of Disease 421
Beyond Prevention of Disease 423
Health Potential Programs for People? 425
The Second Flowering 427
Advances in Molecular Biology: The Know-How 429
Computational Modeling of Physiological Processes: The Models 429
Ubiquitous Computing and Intelligent Sensors: The Personal Specs 430
The Internet: The Information Infrastructure 433
Not Automating,hellip Obliterating 433
Notes 437
Subject Index 459