Why We Eat (Too Much) Read online

  Dr Andrew Jenkinson

  * * *

  WHY WE EAT

  (TOO MUCH)

  The New Science of Appetite

  Contents

  List of Illustrations

  Introduction

  PART ONE: LESSONS IN ENERGY

  How Our Body Works to Control Weight 1 Metabology for Beginners

  How Our Weight is Controlled

  2 The Sacred Cow

  How Genetics, Epigenetics and Food Control Our Weight Set-Point

  3 Dieting and the Biggest Losers

  Why Our Metabolism Can Change Dramatically

  4 Why We Eat

  How Our Appetite (and Satiety) Works

  5 The Glutton

  Understanding the Fatness Hormone

  6 The Last Resort

  How Weight-Loss Surgery Works

  PART TWO: LESSONS IN OBESOGENICS

  How Our Environment Determines Our Weight 7 The Master Chef

  Why Cooking Matters

  8 The Heart of the Matter

  How Poor Nutritional Science Led to Bad Eating Habits

  9 The Omega Code

  Is Obesity a Deficiency Disease?

  10 The Sugar Roller Coaster

  Glucose, Insulin and Our Weight Set-Point

  11 The French Paradox

  Saturated Fat, Nutritional Advice and Food Culture

  12 The Miracle Diet Book

  Why You Should Stop Dieting

  13 The Fat of the Land

  Life Events, Hormones, Geography and Your Weight

  PART THREE: BLUEPRINT FOR A HEALTHIER WEIGHT

  The Secret to Lasting Weight Loss 14 Prepare to Do It Yourself

  Preparing Your Home and Mind

  15 Eat More, Rest More

  Lowering Insulin and Cortisol

  16 Your Personal Blue Zone

  Improving Cell and Muscle Metabolism

  Epilogue: Why Do We Eat Too Much?

  Appendix 1: The Cholesterol Debate

  Appendix 2: Glycaemic Load and Omega-3 to Omega-6 Ratio of Common Foods

  References

  Glossary

  Bibliography

  Acknowledgements

  Index

  About the Author

  Dr Andrew Jenkinson is a consultant surgeon with a special interest in advanced laparoscopic, or keyhole surgery. He is part of an expert team developing advances in gastrointestinal (stomach and bowel) surgery at University College Hospital in Bloomsbury, central London.

  List of Illustrations

  Figures

  Figure 1.1 Energy used per day

  Figure 1.2 7,000kcal translate to 1kg of weight gain

  Figure 1.3 Obesity rates, 1970–2010

  Figure 1.4 Unpredicted changes in metabolism after weight gain and weight loss

  Figure 1.5 The weight set-point

  Figure 2.1 Weight frequencies in hunter-gatherer tribes

  Figure 2.2 Weight frequencies in farming communities

  Figure 2.3 Change in population size with processed food

  Figure 2.4 Actual change in weight of population after the switch to a Western diet

  Figure 2.5 Nutrition in pregnant mothers

  Figure 3.1 Changes in metabolism six years after The Biggest Loser show

  Figure 3.2 Weight gain in mice on a weight-cycling diet

  Figure 3.3 The difference between the highest and the lowest metabolizers

  Figure 4.1 The appetite and satiety hormones in the gut and fatty tissue

  Figure 4.2 The on-switch – appetite hormone levels before and after a diet

  Figure 4.3 How the action of leptin aids a reduction to the weight set-point

  Figure 4.4 How leptin can act to cancel out weight loss through dieting

  Figure 5.1 The vicious cycle leading to leptin resistance

  Figure 6.1 The gastric bypass and the gastric sleeve

  Figure 6.2 After dieting, a new weight set-point is established

  Figure 7.1 Density of brain mass in humans

  Figure 7.2 Cooked food and the GI tract

  Figure 7.3 Cro-Magnon man

  Figure 7.4 The hunter-gatherer food pyramid – if it had existed

  Figure 8.1 Increase in sugar consumption from 1822 to 2000

  Figure 8.2A Correlation between total fat consumption and mortality from coronary heart disease in seven countries

  Figure 8.2B Correlation between total fat consumption and mortality from coronary heart disease in twenty-two countries

  Figure 8.3 Consumption of added fats and oils 1970–2005

  Figure 8.4 Hunter-gatherer food pyramid

  Figure 8.5 Modern food pyramid

  Figure 8.6 The history of humans’ relationship with food

  Figure 9.1 US obesity rates, 1960–2008

  Figure 9.2 US added fat intake per person, 1960–2009

  Figure 9.3 US daily calorie consumption before the obesity crisis (c.1970) and after the peak of the crisis (c.2010)

  Figure 9.4 Composition of fat molecules

  Figure 9.5 Composition of a saturated fatty acid

  Figure 9.6 Composition of omega-3 and omega-6 fatty acids

  Figure 9.7 Amounts of omega-6 and omega-3 present in common household oils and spreads

  Figure 9.8 Increasing levels of omega-6 in American citizens, 1961–2008

  Figure 9.9 The inflammatory chemicals of omega-6 and omega-3

  Figure 9.10 Vegetable oil intake and obesity rates in the USA, 1970–2010

  Figure 10.1 The blood sugar roller coaster

  Figure 16.1 The five original blue zones

  Appendix 2: Glycaemic load and omega-3 to omega-6 ratio of common foods

  Tables

  Table 8.1 The effects of smoking on rates of heart disease

  Table 9.1 Characteristics of omega-3 and omega-6

  Table 9.2 Omega-6 to omega-3 ratios in various populations

  Table 16.1 The glycaemic load of common foods

  Introduction

  Bariatric Surgery Outpatients Clinic, London, December 2012

  Clinic K is where people come to discuss having their stomach removed.

  The office, occupying a whole corner of University College Hospital’s first floor, has a backdrop of London through large floor-to-ceiling windows. Looking out onto the red buses and black cabs of Euston Road, I remember recognizing one of my patients slowly making her way over to the hospital’s main entrance, sheltering her large body under a flapping umbrella in the storm, vainly trying to keep dry for her appointment. I felt sad for her.

  Minutes later she entered, trepidation and despair etched on her face. She had finally given in, held up the white flag, surrendered in her battle with her weight – she had lost the diet wars. She wanted me to remove most of her stomach. She eased herself into our over-sized clinic chair and tearfully recounted her years of dietary failure. And as she talked I listened and learned.

  Why We Eat (Too Much) was inspired by patients just like this lady – normal people who had suffered with their weight for years; people who came to me looking for treatment.

  My patients encouraged me to write this book. I had listened to them over the years and what they said did not fit with my own understanding of obesity. I wanted to close this gap between what scientists, doctors and dieticians told us about it, and how to deal with it, and what obese people actually experienced – because the two stories did not fit together. Someone had got it wrong.

  If, as the scientists told us, it was simple to lose weight by dieting and exercise, and if the benefits of that weight loss were so great in terms of happiness, confidence, health and finances, then why could people not achieve it? Over the next five years I became intrigued by this question: why something seemingly
so simple could in practice prove to be so difficult. Why can’t people sustain weight loss? How could weight loss through dieting be so difficult that people resorted to such extreme measures as stomach-removal (or bypassing) surgery?

  University College London Hospital (UCLH) has a fantastic metabolic research unit, run by my colleague Professor Rachel Batterham. Her cutting-edge research gave me a head-start in understanding how our appetite is controlled by strong hormones (originating in the stomach and intestines) that have a profound effect on what we eat and how much we eat. Appetite did not seem to be under a great deal of conscious control; instead, it was governed by these newly discovered hormones.

  My studies took me from appetite on to metabolism. How is the amount of energy that we burn controlled? More hormones seemed to be involved. But, curiously, much of the ground-breaking research that explained our metabolism was being ignored by mainstream medicine. Why was this?

  If our appetite and our metabolism are being controlled by powerful hormones, then this would explain why it is so difficult for my patients to lose weight using simple willpower. The hormonal triggers that drive our eating and resting behaviour seem to be mainly influenced by our changing environment.

  In this book, I will use the newly emerging scientific understanding of metabolism and appetite and combine this knowledge with what obese people have been trying to tell us for years. I will explain why most of the things that you have been told about obesity are myths, based on poor research and vested interests. I will explain:

  Why it is so difficult to lose weight if you use the current advice from medical and nutritional experts

  How some of this dietary advice can be counter-productive and make weight loss even more difficult

  The best strategies for long-term weight loss and health, whether you want to lose 5lb or 5 stone

  Why many very obese people have the feeling that they are trapped and cannot escape, no matter how hard they try.

  Once you have read this book you should have a better understanding of why medical professionals have been failing in their advice on weight loss for so many years and, more importantly, you will be able to use this knowledge to improve your own health and wellbeing. By the end of this book I hope that you will feel a sense of relief that, finally, you have not only an explanation, but also a solution. I will avoid excessive medical jargon (and explain any terms that need to be used) and present my ideas in an accessible (sometimes light-hearted) way to keep you reading.

  But first, some background. I am a surgeon at University College Hospital in London. My job is to treat people who cannot lose weight by dieting and have reached the end of the road. They have accepted that for them it is impossible to lose weight and keep that weight off. They know that unless something drastic is done they will spend their lives feeling trapped beneath layers of fat, slowly getting sicker and more frustrated and unhappy. In the last fifteen years I must have interviewed over 2,000 people in this situation.

  The solution my patients seek is surgery. Not surgery like liposuction to suck out the fat, but an operation that will change their stomach and intestines to make it easier for them to lose weight: bariatric surgery. You may have heard about this type of surgery in the media. A popular bariatric operation is the ‘gastric band’. This entails having an adjustable band (made of a type of plastic) placed around the upper part of the stomach. The band works by stopping you eating very fast – making you feel full (and sometimes uncomfortable) after a very small meal. The gastric band has now been overtaken in popularity by two other procedures: one where the stomach is completely bypassed (so food doesn’t ever see the stomach), and another where three quarters of the stomach is completely removed, leaving what remains in the shape and size of a narrow tube. This is called the sleeve gastrectomy (more on this in chapter 6).

  My first weight-loss operation was a gastric bypass in 2004, using laparoscopic, or keyhole, surgery. This is quite a difficult procedure to perform. I had been trained well, but when the morning of the operation came, and I saw my patient, I was anxious for him. He was high risk: a very large 210kg (33-stone) young orthodox Jewish chef called Jac.

  The surgery went well. It had taken two and a half hours, although it hadn’t felt that long. Once you are performing a procedure you concentrate so hard it is as if you have been sent to a different world. When you begin, you do not usually feel nervous about all the responsibility because you know that you should be able to deal with most problems if they arise. Performing an operation, especially if you have become familiar with it, can almost be a meditative, deeply relaxing experience.

  Jac made a great recovery, and because keyhole surgery means that there are no large cuts in the abdomen – only small nicks – the pain afterwards is minimal. Happily, he walked out of the hospital pain-free soon after surgery.

  Many of my fellow doctors think that bariatric procedures are unnecessary and mutilating. They think, or say, ‘Why can’t your patients just lose weight on a diet and have a little bit more willpower?’ And it is not just doctors who think this. Many politicians and journalists, people who wield real power, would also argue that this type of surgery should not really be necessary, or available. My belief is that they are wrong. This book sets out to explain our fundamental misunderstanding of the causes of and treatments for obesity. And it is because of this flawed thinking by many experts and advisers that the obesity crisis has become worse and anyone who suffers from it gets more frustrated. If we, as a society, understood obesity and came together to tackle it, then we would not need my services, or the services of any weight-loss surgeon.

  After my first successful operation in 2004, I started to do more and more of this type of bariatric surgery: gastric bypass, gastric bands and sleeve gastrectomies. As I became more proficient at them, the Homerton University Hospital, where I first started as a consultant, grew to be the busiest weight-loss surgery centre in London. With experience, the time I required for an operation was reduced to one hour and most patients needed to stay in the hospital for only one night and then needed just a week off work.

  As the months and years passed, my outpatient clinic became increasingly swamped with patients suffering with different degrees of obesity. I spoke to many hundreds of patients about their views of the condition and what they had experienced first-hand. Then I had a revelation: they all seemed to be saying the same things to me repeatedly. There was no collusion between patients – they did not know what others might have been saying. Their views and their experiences of obesity went against the conventional view of doctors, dieticians and other health professionals. As they vocalized their thoughts, I started to listen and think.

  I recalled the teaching of David Maclean, an immaculately dressed surgeon I had worked with at the Royal London Hospital who, at the age of sixty-eight, had carried on working past retirement age because they could not find an adequate replacement for him. He would look me in the eyes and say, ‘Always listen closely to what your patients are telling you.’ This advice stayed with me – I listened. These were some of the typical things that I heard, time and time again:

  ‘I can lose weight, doctor, but I can never keep it off’

  ‘I think that I have a slow metabolism compared to other people I live with’

  ‘I think obesity is in my genes’

  or

  ‘Diets don’t work for me, I have tried them all and I end up gaining more weight than when I started the diet’

  ‘I only have to look at a cream cake and I get fat!’

  ‘I can’t control my hunger, I feel weak if I don’t eat.’

  When I first started doing these clinics I relied on my limited training in obesity from medical school. I had become very good at doing the operations to treat the condition but, as with many doctors confronted with a patient suffering with obesity, I had poor empathy – I didn’t really appreciate what they were experiencing. I understood the simple principle of energy balance – if you take in mo
re energy in the form of (food) calories than you burn off (through exercise), then you will store that extra energy inside your body as fat. Therefore, in my mind, it was very simple to lose weight. You merely had to eat less and exercise more – that’s how us medics understood it, but it didn’t seem that simple to my patients.

  What also struck me in those first few years of treating obesity was the transformation of my patients after the surgery. Their lives had been turned around. This condition, obesity, that they had been fighting all their lives, was no longer present. Many said they were back to their former selves – their pre-obese selves. The problem that they had been trying to deal with for years and years, with diet after diet, and disappointment after disappointment, was now gone. They had been released from their obesity trap.

  Realizing that each of my patients was telling me virtually the same story before surgery, and that they had become different people after surgery, I started to wonder whether what they, the patients, were saying was correct, and what we, the doctors, were saying was wrong – whether our conventional understanding of obesity was flawed. Was this a condition that arose in patients without them having any control over its development? In other words, was it more of a disease than a lifestyle choice? I wanted answers to these questions.

  The tabloid journalists, the doctors, the policy-makers, the public and the politicians were pointing their fingers at my patients and saying, ‘This is your problem, you made it and if you had enough willpower you could solve it.’ But my patients were giving me a different message: ‘I will do anything, but I am trapped.’ So I thought that I should try and establish the truth. What if my patients were right and the medical establishment was wrong? I went back to the books and I studied and researched the whole area of metabolism, weight regulation and appetite. I wanted to square what I had heard and seen from my years of speaking to and treating obese patients with what was in the medical research literature. I embarked on a further journey into the depths of metabolic research, into the genetics and epigenetics of obesity, how anthropology, geography and economics affected our foods, and how scientists and lobbyists influenced our understanding.