How To Reverse Type 2 Diabetes and Prediabetes E-Book

Dr David Cavan

• Herausgeber: Allen & Unwin
• Kategorie: Ratgeber
• Sprache: Englisch

Seitenzahl: 559

Veröffentlichungsjahr: 2022

Beschreibung

'We have eaten our way into this epidemic of diabetes, what if we could eat our way out of it? Read this book to find out how!' Dr David Unwin, clinical expert in diabetes How to Reverse Type 2 Diabetes and Prediabetes provides an effective and evidence-based approach to guide people with type 2 diabetes and prediabetes towards a healthier future. Focusing on the lifestyle changes that help reverse the diabetes disease process, the book will be an invaluable source of hope and inspiration for the millions of people with type 2 diabetes and prediabetes around the world. Drawing upon Dr Cavan's extensive research into diabetes management and his professional experience, How to Reverse Type 2 Diabetes and Prediabetes reveals the latest scientific evidence behind his innovative approach in helping people reverse their diabetes, providing specific advice for people with prediabetes as well as those with type 2 diabetes. Explaining in easy-to-understand terms how today's lifestyles are driving millions of people into prediabetes and then on to developing type 2 diabetes, the author then describes the changes we can make to halt the process in its tracks, and help people turn around their health to look forward to a future free from diabetes. Advocating a diet based on healthy fresh foods that avoids sugars, refined carbohydrates and other highly processed foods, and with simple suggestions for how to incorporate physical activity into the daily routine, this accessible guide shows us sustainable and achievable ways of adjusting our lifestyles to reverse prediabetes and type 2 diabetes, authenticated with first-hand testimonies from people who in following Dr Cavan's evidence-based approach have already done just that. Previously published as Busting the Diabetes Myth 'Excellent book - written for patients but also great for clinicians' - Amazon 5-star reader review '[Busting the Diabetes Myth] should be compulsory reading for anyone recently diagnosed.' - Amazon 5-star reader review 'Full of valuable information about the condition and how to beat it' - Amazon 5-star reader review

Leseprobe

Dr David Cavan is an experienced diabetes physician, based at the London Diabetes Centre and at University Hospitals Dorset. He has a passion for supporting people with diabetes and, in addition to writing books, has developed a number of self-management programmes. He currently works internationally to train health professionals, and to develop programmes to help people reverse type 2 diabetes.

www.thediabetesdoctor.co.uk

@drdavidcavan

Also by Dr David Cavan

Reverse Your Diabetes: The Step-by-Step Planto Take Control of Type 2 Diabetes

Reverse Your Diabetes Diet: The New Eating Planto Take Control of Type 2 Diabetes

Take Control of Type 1 Diabetes

The Low-Carb Diabetes Cookbook

Previously entitled Busting the Diabetes Myth: The Natural Way to Reverse Type 2 Diabetes and Prediabetes, this book was first published in trade paperback in Great Britain in 2022 by Allen & Unwin, an imprint of Atlantic Books Ltd.

This paperback edition first published in Great Britain in 2024 by Allen % Unwin, an imprint of Atlantic Books Ltd. Copyright © Dr David Cavan, 2022

The moral right of Dr David Cavan to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act of 1988.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of both the copyright owner and the above publisher of this book.

10 9 8 7 6 5 4 3 2 1

A CIP catalogue record for this book is available from the British Library.

Paperback ISBN: 978 1 83895 458 1

E-book ISBN: 978 1 83895 457 4

Printed in Great Britain

Design benstudios.co.uk

Allen & Unwin

An imprint of Atlantic Books Ltd

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www.atlantic-books.co.uk

Dedicated to Mary,my amazing wife, soulmate, counsellorand fellow traveller

Contents

FOREWORD

PREFACE

PART ONE

Introduction

CHAPTER 1

You CAN do it

CHAPTER 2

What are prediabetes and type 2 diabetes?

CHAPTER 3

The implications of a diagnosis of type 2 diabetes

PART TWO

Busting the myths

CHAPTER 4

Diabetes is not your fault

CHAPTER 5

Prediabetes and type 2 diabetes can be reversed

CHAPTER 6

There is such a thing as a ‘diabetic diet’

CHAPTER 7

You can eat cheese

CHAPTER 8

Do test your blood glucose levels

CHAPTER 9

Exercise is not the answer

CHAPTER 10

You do not need to eat breakfast

PART THREE

Helping you on your way

CHAPTER 11

Step by step towards your new way of eating

CHAPTER 12

Making changes and sticking to them

CHAPTER 13

The role of medication

CHAPTER 14

Looking after your mental health

CHAPTER 15

Situations that require special attention: illness, stress and pregnancy

CHAPTER 16

The importance of regular health checks

CHAPTER 17

Getting support

CHAPTER 18

Be inspired

CHAPTER 19

Achieving your goals and celebrating your successes

PART FOUR

Recipes

About the recipes

EGGS

SOUPS

TAKEAWAYS

FAMILY MEALS

DESSERTS

APPENDIX A

Useful websites and further reading

APPENDIX B

BMI chart

ENDNOTES

ACKNOWLEDGEMENTS

INDEX

FOREWORD

A beacon of hope in a very dark world

By Dr David Unwin FRCGP, RCGP clinical expert in diabetes

I am an oldish (63 years old) GP who has looked after my local population (near Liverpool) of about 9,000 people since 1986. A few days ago I was so excited to meet my 105th patient to accomplish drug-free remission of her type 2 diabetes. That is, her blood tests showed she had non-diabetic blood sugar levels and she was no longer taking her medication for diabetes. This was a lady who only a few months ago thought her diabetes was a chronic, deteriorating condition and is now medication-free with a normal blood sugar level. She is rightly proud of her achievement! A beacon of hope in a very dark world. I agree with the author of this book, my good friend Dr David Cavan, that it is high time that the myth that type 2 diabetes is a condition that only gets worse with time was debunked.

Another pandemic.

When I started as a young GP 35 years ago there were just 57 people with diabetes in our practice; it was quite a rare illness, as was the obesity it is so often associated with. Also, it affected older people. This is important as type 2 diabetes does its damage via raised blood sugar as a function of time so older people have less time for damage to accrue. By 2012 diabetes was no longer rare – my practice had suffered an eight-fold increase to 472 cases! A situation made worse because the individuals were decades younger. The youngest case I have seen is just ten years old! As part of this phenomenon, amputations, heart disease and blindness had become depressingly commonplace. My answer to helping these patients was to use ever more drugs to try and reduce their blood sugar levels. Exactly the same treatment model is still occurring in practices right across the world. Yet the idea that drugs will ever be the answer to the epidemic of diabetes is another myth. In England we now spend over £600 million on drugs for diabetes each year, yet still the cases keep rising, to over four million people now having diabetes in the UK. This is a global phenomenon; another worldwide pandemic, now killing over four million people each year.

It’s not just about type 2 diabetes. It may be a surprise to learn the information in this book could help with far, far more than just diabetes. For example, about 25% of adults in the developed world now have non-alcoholic fatty liver disease (NAFLD) – yet another global problem. The wonderful work of Professor Roy Taylor in 2012 showed not just how a fatty liver interfered with the work of insulin, causing so-called insulin resistance and eventually diabetes itself, but also how this and even type 2 diabetes could be reversed by a better diet and weight loss. NAFLD and type 2 diabetes are associated with yet another epidemic; central obesity (having a big belly), which is linked to the increased risk of at least eight different cancers, plus high blood pressure and cardiovascular disease.

So in addition to improving blood sugar control, if you follow Dr Cavan’s advice in Busting the Diabetes Myth you may also see significant weight loss, better blood pressure, improved lipid profiles and liver function tests – not to mention better self-esteem! Key to achieving all this is improving your understanding of the role the hormone insulin plays in type 2 diabetes, which is explained in Chapter 2. If you have insulin resistance you will struggle to control your blood sugar – but the central and hopeful point being made here is that insulin resistance is reversible. This book explains how this can be brought about in terms the interested reader can easily understand.

I hope that by reading this well-organized, clever book you will have a far better understanding of not just the causes of type 2 diabetes but also what you may be able to do to improve diabetic control and indeed many other aspects of your health.

We have eaten our way into this epidemic of diabetes, what if we could eat our way out of it? Read this book to find out how!

Dr David Unwin FRCGP, RCGP clinical expert in diabetes

@lowcarbGP

Preface

I have worked as a diabetes specialist for over 30 years, and it is fair to say that for the first 20 of those years, managing people with type 2 diabetes was of little interest to me, unless they had developed complications that needed my specialist input. Less complex cases were managed by GPs. Until ten years ago, we believed that type 2 diabetes was an inevitably and inexorably progressive condition that would get worse as time went on, and so managing it was all rather depressing for me as a doctor. It must have been even more depressing for my patients, who were asked to make lifestyle changes and to take medication, often with unpleasant side-effects, in order to control a condition that they had been told will in any case likely progress. To make matters worse, they were advised to base all their meals on starchy carbohydrates, which meant that every time they ate, their food caused their blood sugar levels to increase, just as they were taking medication to decrease their sugar levels. It is no wonder that many who followed the advice they were given felt they were failing in some way.

All that changed in 2011. By then we had seen a number of new diabetes drugs come on stream, often with great hope and even more hype, but which I felt just failed to live up to expectations. I was becoming disillusioned with the use of medications to manage type 2 diabetes. At about the same time, we were beginning to learn that what we had believed about type 2 diabetes being a progressive condition was not necessarily true; that in fact it could be reversed by lifestyle change. And so, for the first time in my career, I started to ask people with type 2 diabetes about their diet and their lifestyle. I began to suggest that they ignore the official advice and strive to reduce the carbohydrates in their meals. Those that did found that their blood sugar levels improved and often they needed to reduce their medications. One of my early patients was visiting from Nigeria, and by changing his diet he was able to stop insulin injections, which back home were very expensive for him to buy. For the first time in my career, I became really excited about the prospect of treating people with type 2 diabetes. So much so, that when a couple of years later I was asked to write a book for people with type 2 diabetes, I leapt at the opportunity to share my new understanding and ideas, to give people hope that they could potentially reverse their condition and provide some tips as to how they could achieve it, principally by reducing the carbohydrates (sugars and starches) in their diet.

That book, Reverse your diabetes: the step-by-step plan to take control of type 2 diabetes, was published in 2014. To be honest, I was rather nervous about what might happen next. It was (and still is) quite rare for a diabetes specialist to write a book to advise people to ignore standard dietary advice and to consider reducing their medications. So much so that it caused quite a stir in some of the upper echelons of the diabetes establishment. Some thought I was jeopardising my reputation and my career for a fad diet. I didn’t think they were right, but I didn’t know for sure. I didn’t have to wait long to find out. Within a few months, people contacted me to tell me that they had followed my advice and reversed their diabetes. I then began to hear about other doctors in the UK and overseas who had similar ideas and were also seeing great success with their patients. Since then, they and I have been on a journey during which our understanding about reversal or remission of type 2 diabetes has increased enormously. This journey has taken me to different countries to help doctors adopt the same approach for their patients. And you know what? My experience is that regardless of culture, race or income level, people who get the right support are able to make changes that significantly improve their health, even if they do not manage to fully reverse their condition.

Things are beginning to change. There is now greater acceptance that type 2 diabetes can be reversed, and that a low carbohydrate diet can help people achieve that. Despite this, I still come across many health professionals who are sceptical about reversal of type 2 diabetes, and so many of their patients continue to follow the old ways of managing their diabetes, oblivious that there is an alternative. They are following and believing what I now term the ‘diabetes myths’, and so it is my aim in this new book to show what I believe those myths to be and bust them, one by one, using the latest evidence and my own experience. As with Reverse your diabetes, I also include detailed explanations about how type 2 diabetes develops, the consequences of having type 2 diabetes (brought sharply into focus during the Covid-19 pandemic), and the treatments available, as I believe it is important that people with type 2 diabetes have a good understanding of their condition, so that they are fully informed when making choices as to how they want to manage it, and whether they want to try and reverse it. I have also included real life stories from people who read Reverse your diabetes and did just that, and from others who used different resources to reverse their diabetes.

The biggest myth is that type 2 diabetes is a progressive condition. It does not have to be, and in this book I explain what you can do to minimize the chance that it progresses and maximize the chance that it reverses. You do not have to have type 2 diabetes to benefit from this book. Prediabetes is the precursor to type 2 diabetes and if you have prediabetes, many of the same principles I put forward here will help ensure not only that you do not progress to type 2 diabetes, but also that you increase the chances that you can reverse your prediabetes and again achieve normal blood sugar levels. So, whether you have prediabetes, are newly diagnosed with type 2 diabetes, or have had type 2 diabetes for many years, my hope is that this book will help you achieve long-lasting improvements in your health and wellbeing.

PART ONE

Introduction

CHAPTER 1

You CAN do it

The biggest myth about type 2 diabetes is that it is a condition that just gets worse over time, and there’s nothing you can do to stop that happening. This is a view that is firmly held by many people, including some health professionals. There is a good reason for this – we used to believe it was true. However, that was a long time ago. It is nearly 20 years since we first learnt that type 2 diabetes can be prevented, and over 10 years since we learnt it can be reversed. Stories of people reversing their diabetes are now quite common in the media, and you may well know someone who has managed to do just that. And yet, too many of my medical colleagues still treat their patients as if nothing has changed, as if what they were taught 30 years ago still takes precedence over more recent scientific advances in understanding. And if one of those people is a doctor or nurse helping you manage your diabetes or prediabetes, that can be quite disconcerting. Diabetes UK, which exists to support people with diabetes, states: ‘At some point, most people with type 2 diabetes will need to take medication to help them manage their blood sugar levels', implying that medication is the norm and to be expected.’1 It acknowledges that some people are able to put their diabetes into remission, but it goes on to say that this is not possible for everyone. While this is true – it is not possible for everyone – the way it is presented gives a subliminal message that goes something like this: well, it is possible to reverse type 2 diabetes, but it’s very difficult and most people aren’t up to it, and so you will probably need medication to control it.

I feel this is an unnecessarily and umabitiously defeatist approach and I often compare this with that of doctors who treat cancer. Some cancers have a very high likelihood of causing death, and yet there could be treatments that provide a small chance of achieving remission. I have personal experience of this from some years ago, when my father was diagnosed with an aggressive form of leukaemia. It was resistant to normal treatments but there was a more complex therapy that offered the possibility of success in controlling the disease. We all understood that he was very ill, and I guess deep down I knew he would not recover, but the team looking after him focused on the positive, on the slim chance that the treatment could help him pull through. During this time, a nurse kindly and gently encouraged me to stay positive by saying to me, ‘There is always hope.’ Those words, and that wider focus on the positive, greatly helped me through that time, even though his condition took a turn for the worse before he was able to start the treatment, and he died shortly afterwards.

Now the chances of achieving remission of type 2 diabetes are a lot higher than my dad’s chances of overcoming his illness. Yet many health professionals seem to focus on the negatives – it’s hard work and most people won’t manage it. However, gradually and begrudgingly, the understanding that it is possible to reverse type 2 diabetes is replacing the myth that type 2 diabetes is a condition that only gets worse. Since my last book, Reverse Your Diabetes, was published in 2014, there have been numerous research studies showing that many people have been able to reverse their diabetes. In addition, I have been contacted by many people who had read my book and told me with great joy how they too have been able to join the ranks of those whose diabetes is in remission. You can read some of their stories later in this book.

So what do we mean by reversal and remission of type 2 diabetes? In August 2021, an international consensus statement was published by the American Diabetes Association, the European Association for the Study of Diabetes and Diabetes UK, which defines remission as achieving non-diabetic levels of glucose in the bloodstream for at least three months, while taking no diabetes medications.2 This is usually judged by means of a blood test of glycated haemoglobin level or HbA1c. HbA1c provides an overview of diabetes control over the previous six to eight weeks – so it is a sort of average blood glucose level. A level of 48 mmol/mol (millimoles per mole – the standard way of measuring HbA1c – also represented as 6.5 per cent) or less, without using diabetes medication, indicates remission of type 2 diabetes. Remission of prediabetes is achieved if the HbA1c is maintained below 42 mmol/mol (6.0 per cent). Chapter 2 explains all this in more detail.

This statement also recommended that remission be the preferred term to reversal of diabetes. However, I like the term reversal and I also think there is a slight difference. I explain reversal as the process by which people can reverse what I call ‘the diabetes disease process’, which will also be explained in more detail in Chapter 2. By making lifestyle changes, people can reverse the disease process that caused their diabetes (or prediabetes). In some, the reversal will be complete, their metabolism will have normalized and they will have achieved remission; but others may reverse the process to some extent. They may lose weight, successfully reduce their doses or number of medications and achieve better control of their diabetes, but still have the condition. In other words, they could be described as having partially reversed their diabetes. They did not achieve remission, but nevertheless, they have significantly improved the outlook for their health for many years to come.

What does that mean for you? If you have recently been diagnosed with prediabetes or type 2 diabetes, there is a high likelihood that if you are able to make lifestyle changes, then you can reverse the metabolic abnormalities that drive the diabetes disease process. You might be able to reverse the condition completely, so that your diabetes is in remission, or you might be able to achieve much better control of your condition, perhaps with less need for medication. Although you will still be classed as having diabetes (or prediabetes), you will have busted the myth that type 2 diabetes is likely to get worse and require ever more medication.

If you have had type 2 diabetes or prediabetes for many years, the research suggests that complete reversal is less likely than in people who have been diagnosed more recently. However, I have known people achieve remission after many years of having type 2 diabetes, in some cases having been on insulin injections, and so can confirm that it is never too late to make lifestyle changes that will maximize the chance of reversing the disease process. Therefore, regardless of how long you have had type 2 diabetes or prediabetes, it is definitely worth considering making some changes to your lifestyle – they just might work! And with the knowledge gained during the Covid pandemic about the increased risks associated with having diabetes, it has arguably never been so important to try.

Now the fact that you are reading this book is a good start, and hopefully indicates that you are open to making some changes to improve your health. As you read on, you will gain valuable information that you can use to make choices about your diet and lifestyle to help improve your health. I deliberately used the word ‘choices’ there, to emphasize that any process of lifestyle change is by definition your choice, and yours alone. In this book I will provide advice – not insist you make sudden and radical changes to what you eat or how you live. My goal is to provide you with information that will offer you good options, and then it is up to you to decide whether you want to make any changes, which changes you want to make and when you want to make them. The whole point of lifestyle change is to make changes that will be long-lasting. They therefore have to be changes that are sustainable in the long term. That means you have to be fully on board with – and committed to making – those changes.

And the changes you make are not for my benefit or your doctor’s benefit or anyone else’s benefit. They are solely for your benefit. So rather than just coming up with a list of changes that you think you should make, or that you feel you would like to make, I suggest that, first of all, you consider why you want to make changes – in other words, what it is that you want to achieve in respect of your health. That is what I call goal-setting.

You see, just like those colleagues of mine who tend to focus on the negative, you too may be experiencing similar negative feelings. Maybe you have had diabetes for many years, and have tried to ‘follow the rules’ but always found that your glucose levels are too high. Maybe you have just been diagnosed with diabetes, but have struggled with being overweight for much longer. Perhaps you have tried different diets, maybe managed to shed a few pounds, but it was hard work, and you ended up back at square one. Maybe you have come to accept you will always be overweight, or unhealthy, as if you have constructed your own myths. That would be quite understandable. It would also be understandable if you felt cynical about your ability to turn things around, to bust your own myths.

However, I am inviting you to focus on something else – not on the negatives, however much they have been part of your experience. Rather, focus on the positives – the ‘what ifs’. Growing numbers of people in many countries have experienced the positive life-changing effect of reversing their diabetes or prediabetes. They have proved to themselves that it is possible and they are enjoying life in a way that just a short while ago they could not have imagined. Reversing diabetes is possible. Losing a lot of weight is possible. Regaining the energy you had 20 years ago is possible. Being able to reduce or stop medications for diabetes is possible. Doing away with tablets for high blood pressure, pain, erectile dysfunction, gout and heartburn is possible. I have had patients who have been able to come off medications for all of these conditions. Now, I never make promises to people about what will be achievable for them, as this depends hugely on how their body responds to the changes they are able to make, but I can say that, if you are able to follow the advice in this book, there is a high likelihood of improving your health and wellbeing in some – or many – of these ways.

I have already mentioned that the changes that will help restore your health need to be long term. Not a short, sharp shock, not a crash diet, but forever. Changing what, when or how you eat, will by definition mean changing long-held habits, many of which will be so ingrained into your daily life that you may not realize quite why you eat what you do, when you do. It is possible – indeed very likely – that, after following a new way of eating for several months, at some point you will find yourself back with your old habits, either because you slip into autopilot without realizing or because you have hit a difficult time. Life has a habit of throwing a spanner in the works, often with no warning and often when you least expect it. When that happens, you will need to get yourself back on track and remotivate yourself, so it helps to have in mind some really good reasons for getting back on track.

Which brings me back to your goal. When setting your goal, allow yourself to think, dream even, about what you would like to achieve in respect of improving your health – not only ‘what’ but also ‘why’. For example, if your goal is to lose a lot of weight, rather than thinking about that as just reversing a negative (‘I will no longer be overweight’), focus on some positives that will happen if you do lose weight, such as being able to climb stairs without getting out of breath, being able to play around with the kids, getting into clothes you haven’t been able to wear for years or taking up a sport you used to enjoy. If your goal is to reverse your diabetes, how would that make you feel? Apart from not having to take medications, picture regaining the energy you no longer have and being able to think more clearly. Essentially, imagine the new you.

So, before going any further, I encourage you to ask yourself the questions overleaf, and to write the answers down, either in this book or in a separate notebook. Take some time to really think about them, as we will refer back to your answers as you progress through the book. Maybe you do not feel you can answer all the questions just yet. That’s fine. You can also change your answers at any time. We will return to the questions again in Chapter 11. But before reading any further, have a go now:

1.  What frustrates you most about your health at present?

2.  How do you want things to be different?

3.  How will you feel when you have achieved this?

4.  What is your main goal – the thing you would like to achieve from reading this book?

Identifying your main goal will help you focus not only on the benefits you can look forward to as you achieve it, but also on the changes that you need to make in order to achieve it. In Chapter 11, we will explore how you can set yourself smaller goals representing the changes that will help you work towards your main goal.

Depending on how quickly you read, it may be a little while before you finish this book. So, right at the start, I want to set out some steps that you can take immediately that will help reduce your glucose levels, get you feeling better and set you on the path to reversing the diabetes disease process. I call this my diabetes ‘first aid’ guide – simple steps that anyone can take. You may not feel that they all apply to you, but I would encourage you to look at the list opposite and choose one or two changes that fit with your own goal and that you feel you could make immediately:

First aid guide to taking control of type 2 diabetes

Drinks

1.   Stop using sugar in tea or coffee (use sweeteners if necessary).

2.   Avoid sweet drinks, such as fruit juice, smoothies, squashes and fizzy drinks (drink water or sugar-free drinks as far as possible).

3.   Cut down the amount of alcohol you consume, especially drinks containing carbohydrate, such as beer, cider or sweet wines.

Food

1.   Avoid sweet foods, such as cakes, biscuits, jam, sweets or chocolate.

2.   Eat less potatoes, rice, pasta and bread.

3.   Eat more fresh green and salad vegetables.

4.   Limit fresh fruit to one or two small pieces a day.

Physical activity

1.   If you can, go for a 15-minute walk every day.

2.   Use stairs instead of lifts or escalators.

3.   Walk or cycle instead of using the car or bus for short journeys.

4.   If you use a bus, get off one or two stops before your destination.

These tips reflect the key elements of managing type 2 diabetes in the short term: eating less sugar and starchy food and becoming more active. We will cover these in more detail later in the book but making one or two of these changes now will make a big difference to most people newly diagnosed with type 2 diabetes.

So, please do try to make some changes, however small. If you do not feel you can make any changes right now, you may wish to set yourself a target of one change you feel you could realistically make in the next two weeks. Please do not wait until you ‘know it all’ before making a start. Any changes you make now can be fine-tuned at any time as you go along.

As you make changes, you will hopefully begin to see some improvements quite quickly – in your blood glucose levels and your feeling of wellbeing. Taking control of your diabetes in this way will be the first step towards reversing your diabetes. We will discuss this in more detail later in the book (Chapter 5), but for now the message is that anything you can do to reduce your weight and your blood glucose levels will start the process of reversing the changes in your body that led to type 2 diabetes or prediabetes. And this will lead to a healthier future.

CHAPTER 2

What are prediabetes and type 2 diabetes?

A history of diabetes

The technical name of the condition is diabetes mellitus, which when translated from the Latin literally means ‘passing honey’ – so-called because the urine contains glucose and tastes sweet. It is thought that the condition was first described – three and a half thousand years ago in ancient Egypt – as a disease where urine was too plentiful. Then in 1,000 BC, the ancient Indian physician Sushruta described the urine being sweet, and wrote that ants and flies were attracted to it, but he thought that diabetes was a disease of the urinary tract (kidneys and bladder). He wrote that it could be inherited or develop as a result of dietary excess or obesity (perhaps referring to type 1 and type 2 diabetes). The recommended treatment was exercise. It would take until the 17th century before it was discovered that the urine was sweet because it contained sugar and that diabetes was a disease of the pancreas rather than the kidneys. In 1797, the Scottish military surgeon John Rollo heated the urine of patients until a sugary cake was all that remained. He noted that the volume of the cake increased if the patient ate bread, grains and fruit (high in carbohydrate), but decreased if he or she ate meat and poultry (low in carbohydrate). Demonstrating that there is rarely anything new in the universe, he went on to describe the case of a Captain Meredith who took to a diet low in carbohydrate and high in fat and protein. His weight fell from 224 pounds (102 kg) to 162 pounds (73 kg) and his health improved. At the time, diabetes was reported as being relatively rare and associated with wealth.

At the end of the 19th century, the role of insulin became understood. In 1889, two German physicians working jointly at the University of Strasbourg – Joseph von Mering and Oskar Minkowski – removed the pancreas from dogs. They noticed that this caused the unfortunate animals to urinate frequently on the floor – despite being previously house trained. Testing the urine, they found high levels of sugar, thus establishing a link between the pancreas and diabetes. This was then reversed by the transplantation of small pieces of the pancreas back into the dog’s abdomen.

Piece by piece, the puzzle was being assembled, and by the 1920s it was established that diabetes is characterized by an excess of sugar (glucose) in the blood, resulting in glucose in the urine. The disease was often seen in overweight people in whom it could be controlled by adopting a low-carbohydrate diet. In others, insulin, extracted from animal pancreases and given by injection, led to a fall in blood glucose levels.

Types of diabetes

By the 1970s, it had become clear that there were two distinct types of diabetes:

1.  Type 1 diabetes usually occurs first in children or young adults. It usually comes on quite suddenly with marked symptoms, such as thirst and weight loss, and can only be treated by insulin injections.

2.  Type 2 diabetes usually occurs in later life and it has become increasingly clear that it is related to our modern lifestyles, characterized by unhealthy food and physical inactivity. Its onset is usually far more gradual, without any specific symptoms, and it is sometimes first diagnosed by a blood test done as part of a general check-up.

There are also rare types of diabetes that occur in young people (known as maturity-onset diabetes of the young or MODY). These are inherited conditions that are not associated with weight gain, and there is usually a strong family history of diabetes. Although they mainly present in childhood, most cases can be controlled with tablets rather than insulin like type 1 diabetes.

It has also become apparent that the distinction between type 1 and type 2 diabetes is not as clear-cut as previously thought, and for people who are diagnosed in their forties and fifties, there may be a period of uncertainty before one can definitively distinguish between the two. For example, some overweight adults with type 2 diabetes present quite suddenly with very high glucose levels and require insulin at diagnosis, just like someone with type 1 diabetes. Unlike a person with type 1 diabetes, however, insulin can often be stopped once their condition stabilizes. Conversely, there is a kind of type 1 diabetes that occurs in middle-aged or older people, sometimes referred to as latent autoimmune diabetes of adulthood or LADA. As with type 1 diabetes, people with this condition are not overweight, but the onset is more like type 2 diabetes and they may be treated with tablets (see Chapter 13) for a period. However, within a few years, it becomes clear that tablets are not sufficient to control their blood glucose levels and they need insulin. From that time, their treatment is the same as for someone with type 1 diabetes. This ‘overlap’ between type 1 and type 2 diabetes can result in some people being given the wrong diagnosis and possibly therefore the wrong treatment – sometimes for many years.

Gestational diabetes is a condition in which diabetes occurs during pregnancy. It is similar to type 2 diabetes and is usually managed with dietary change, at least initially, although some people do need medication. It generally reverses once the baby is born, but both the mother and the baby are at increased risk of developing type 2 diabetes in later life.

Diabetes can also arise as a result of other diseases affecting hormones (for example, acromegaly, which is a condition caused by the presence of too much growth hormone, or Cushing’s disease, which is caused by the presence of too much steroid hormone, cortisol). These cases are called secondary diabetes and generally reverse once the underlying condition has been treated. Cortisol is the body’s natural steroid, which is released into the bloodstream at times of stress. It increases blood glucose levels to provide additional energy. Constantly high levels of cortisol can mean the body is unable to produce enough insulin to counter the effect on blood glucose levels, leading to diabetes. People who have been treated with steroids for long periods of time for conditions such as asthma may also develop diabetes. Diabetes also occurs if other diseases affect the pancreas or if the pancreas has been wholly or partly removed by surgery.

While some parts of this book may be helpful to people with other types of diabetes, it is intended specifically for people with prediabetes and type 2 diabetes, to help them learn how to manage – and potentially reverse – their condition. My book Take Control of Type 1 Diabetes provides advice for people with that condition.

Making a diagnosis of diabetes

The typical symptoms of diabetes include excessive urination, excessive thirst, tiredness, blurred vision, weight loss and infections such as thrush. These usually only arise once the glucose in the blood has reached a high level and the kidneys try to excrete the excess glucose in the urine. This explains why glucose can be detected in the urine and its sugary nature provides an ideal environment for the growth of bacteria and fungi, which leads to urinary infections and thrush (candidiasis). In order to excrete glucose, the kidneys need to excrete a larger volume of water (otherwise you would be peeing out sugar lumps) and this leads to dehydration, which in turn leads to excessive thirst. High glucose levels in the eyes leads to blurred vision.

In many cases of type 2 diabetes, people are diagnosed with no or only very mild symptoms. This is because diabetes is being picked up very early as a result of screening blood tests in people who do not yet have any symptoms of the disease. In other cases, people may have had diabetes for some time, which has not been diagnosed. In these cases, blood glucose levels may rise high enough for some of these symptoms to occur.

Diabetes is diagnosed by blood tests. This means that if you have symptoms which you think may be due to diabetes but the blood tests are normal, you do not have diabetes. On the other hand, if your blood tests are diagnostic of diabetes, then you have diabetes, even if you do not have any symptoms.

Diabetes can be diagnosed by a measurement of random blood glucose or fasting blood glucose, by a glucose tolerance test or by an HbA1c test. This can make it very confusing to understand what ‘your numbers’ mean. Furthermore, different units are used in different countries, and for prediabetes, there are also different definitions in different countries. Confused? I often am. That’s why I will explain each test in some detail.

Random blood glucose test

This is often the first test that will be done and can be performed at any time of the day after breakfast. In the UK and many countries, the result is expressed as the amount of glucose molecules per litre of blood – usually expressed in terms of millimoles per litre (mmol/l). In the US and some other countries, the units are milligrams per decilitre (mg/dl). They are interpreted as shown in Table 1.

Table 1: Interpretations of random blood glucose test results

Random blood glucose*

Normal

Prediabetes

Diabetes

mmol/l

Less than 7.8

7.8–11.1

Above 11.1

mg/dl

Less than 140

140–200

Above 200

* Also applicable for the two-hour glucose tolerance test (see below).

If the random blood glucose level is normal, it is unlikely that the person has diabetes; however, if it is in the prediabetes range, then a fasting glucose or HbA1c test can be performed.

Fasting blood glucose test

This is a blood test taken after a fast of 12 hours, during which time only water can be taken by mouth. The test is generally performed first thing in the morning. The results are interpreted as shown in Table 2.

Table 2: Interpretations of fasting blood glucose test results

Fasting blood glucose

Normal

Prediabetes*

Diabetes

mmol/l

Less than 5.5

5.5–7.0

Above 7.0

mg/dl

Less than 100

100–125

Above 125

* Note that the World Health Organization (WHO) does not recognize the term ‘prediabetes’ as a clinical state. Rather, it defines two separate conditions that are broadly equivalent to prediabetes. These are impaired glucose tolerance and impaired fasting hyperglycaemia, as shown in Table 2. However, if that isn’t complicated enough, the WHO defines impaired fasting hyperglycaemia as a glucose level of between 6.1 and 7 mmol/l (110–125 mg/dl), whereas prediabetes is often defined as a fasting blood glucose of between 5.5 and 7.0 mmol/l (100-125 mg/dl).

If both the fasting and random blood glucose levels are normal, then the person does not have diabetes.

Glucose tolerance test

This used to be regarded as the gold standard method for diagnosing diabetes. It has now largely been superseded by HbA1c measurement but for the sake of completeness I have included it as it is still sometimes used. The glucose tolerance test (GTT) is a standardized test where a fasting blood glucose level is measured and then the person is asked to drink a liquid that contains 75 g of glucose. A further blood test is taken two hours after the drink to see how high the glucose level has risen. The results are interpreted in the same way as the fasting and random tests above. If either the fasting OR the two-hour values are diagnostic, then the person has diabetes. In other words, both have to be normal to exclude the diagnosis.

Glycated haemoglobin (HbA1c) test

When the level of blood glucose is higher than normal, the excess glucose attaches to a number of different molecules in the body. For example, when glucose attaches to the lens of the eye, it can lead to the development of cataracts, or if it attaches to soft tissue in the shoulder it may lead to a frozen shoulder. This process of attachment is termed glycation. Red blood cells contain haemoglobin, which is the substance that carries oxygen in the blood cells to the different tissues around the body and gives blood its red colour. A small amount of haemoglobin in each blood cell is glycated and just how much will depend on the amount of glucose present in the bloodstream. Red blood cells last for about four months before they are ‘recycled’, and the amount of glycated haemoglobin in any one cell gradually increases over this time, according to the level of glucose in the blood. Blood glucose levels change constantly according to food intake and activity levels, and so a single measurement is of little use in monitoring diabetic control. The level of glycated haemoglobin (abbreviated as HbA1c), on the other hand, is used to assess glucose levels over a longer period of time, and for many years has been the gold standard means of assessing diabetic control.

Since 2011, HbA1c has become a recognized means of diagnosing type 2 diabetes. Its measurement involves a simple blood test that can be taken at any time of day (as it reflects glucose control over the past six to eight weeks). Historically, HbA1c was expressed as the percentage of haemoglobin that was glycated. In 2011, a new system of units was introduced, which expresses the glycated component as a concentration of the total haemoglobin (millimoles per mole or mmol/mol). However, old habits die hard, and some people still refer to the old percentages. Furthermore, in some countries, the newer units haven’t caught on at all. I will therefore present both units in this book. In people without diabetes, HbA1c is generally below 42 mmol/mol (6.0 per cent). An International Expert Committee has defined a result between 42 and 48 mmol/mol (6.0 and 6.5 per cent) as indicative of prediabetes,3 and the UK and many other countries follow this definition. However, in the US and other countries that follow their guidance, prediabetes is defined as an HbA1c between 40 and 48 mmol/mol (5.7 and 6.5 per cent). Thankfully, all are agreed that a measurement of 48 mmol/mol (6.5 per cent) or above is diagnostic of type 2 diabetes. That said, it is important to be aware that a level below this does not rule out diabetes, and if there is any doubt then a glucose tolerance test should be performed. The HbA1c tests are summarized in Table 3.

Table 3: Interpretations of HbA1c test results

HbA1c (international expert definition)

Normal

Prediabetes

Diabetes

mmol/mol

Less than 42

42–48

Above 48

%

Less than 6.0

6.0–6.5

Above 6.5

HbA1c (US definition)

mmol/mol

Less than 40

40–48

Above 48

%

Less than 5.7

5.7–6.5

Above 6.5

Glycated haemoglobin is also the test used to monitor control of diabetes, to ensure that the recommended treatment (lifestyle changes and medication) is achieving the desired effect. Generally, a level of 50 mmol/mol (6.7 per cent) or below is indicative of good control of diabetes; levels much above 65 mmol/mol (8 per cent) significantly increase the risk of developing diabetes-related complications.

If you have prediabetes and are able to reduce your HbA1c to below 42 mmol/mol or 6.0 per cent (40 mmol/mol or 5.7 per cent in the US!) and keep it there for at least three months, the prediabetes is said to be in remission. Similarly, if you have type 2 diabetes and maintain your HbA1c below 48 mmol/mol (6.5 per cent) for at least three months, without any medication, then your diabetes is said to be in remission.

The role of insulin in keeping glucose levels under control

In order to understand why glucose levels rise in people with prediabetes or diabetes, it is important to understand how insulin controls glucose when everything is working normally.

Glucose is a type of sugar that is used for energy by nearly all types of cells in the body and it is essential that all parts of the body have a steady supply of glucose. This glucose is obtained from the food we eat: all carbohydrates (sugars and starches) that we eat are broken down into glucose, which is then absorbed from the gut into the bloodstream so that it can be carried to the tissues and used as energy. Any spare glucose is taken up into the muscles and liver where it is stored in the form of glycogen. Glycogen in the muscles is then available for later use if the muscles need extra energy (for example, during intensive exercise). Once the glycogen stores are full, any excess glucose is converted to fat and stored in the liver.

While glucose only enters the body when we eat or drink, the body’s cells require a constant supply of glucose in order to function properly. The liver, which releases some of its stored glucose into the bloodstream, provides this service and ensures that just the right amount of glucose is available during periods when we are not eating (overnight, for example). In a person without diabetes the amount of glucose in the bloodstream is kept at around 4–6 mmol/l (70–100 mg/dl).

The level of glucose in the bloodstream is controlled by insulin. Insulin is a hormone produced by the pancreas – an organ that sits just below the ribcage, behind the stomach. Like many of the body’s organs, the pancreas does a lot of different things, but it has two main functions. One is to produce enzymes that are released directly into the small intestine in order to break down food so it can be absorbed into the bloodstream. These enzymes include: amylase, which breaks down starch into glucose; lipase, which breaks down fat; and protease, which breaks down proteins.

The other main function of the pancreas is to produce hormones. These are chemicals that are released into the bloodstream, and which have effects all around the body. Insulin is one of the hormones produced by the pancreas, and its job is to regulate the amount of glucose in the bloodstream, ensuring that cells get the right amount of glucose at all times. It does this in a number of ways:

1.   When we eat a meal, the carbohydrate in the meal is converted into glucose in the gut and passes through the gut wall into the bloodstream. The body detects that the glucose level in the blood is rising and this leads to the pancreas producing additional insulin.

2.   This insulin acts on individual cells to allow glucose to enter them. Insulin molecules attach to a receptor on the cell membrane that opens up to allow glucose in. Insulin is often likened to a ‘key’ that opens the cell’s ‘door’ allowing glucose to enter the cell.

3.   Insulin also stops the liver and muscles from releasing stored glucose into the blood; this allows spare glucose to be added to the glycogen stores.

When we are not eating, the pancreas continually produces a small amount of insulin that controls the release of glucose from the liver. In the liver, insulin acts like a tap that turns off the release of glucose from the liver. If glucose levels in the blood drop too low, then less insulin will be produced, opening the tap and allowing more glucose to be released from the liver. On the other hand, if glucose levels rise, then more insulin is produced, closing the tap and slowing down the release of glucose from the liver. These processes are illustrated in Figure 1.

Figure 1: The role of insulin in controlling blood glucose levels

What goes wrong in prediabetes and type 2 diabetes?

Imagine you are at a train station, waiting for a train. The train arrives and you press the button to open the doors, but the train is so packed with people that you cannot get on. If it is a busy time of day, gradually the station will become full of people unable to get onto a train.

This is a bit like what happens to glucose trying to get into the cells of a person with type 2 diabetes. In someone who has taken in more energy than they need in their food and drink, it is as if their body’s cells are so full that, when insulin opens the cell doors, there is no room for the glucose to go in as it is already jam-packed.

Unlike in type 1 diabetes, where there is a complete lack of insulin (so the doors can’t open), in type 2 diabetes there is insulin present, but it is ineffective in enabling glucose to enter the cells, as they are already full of glucose. So the amount of glucose in the blood increases. As the glucose levels increase, the pancreas produces more insulin to try to push the glucose into the cells. They are already full, so instead glucose is taken up into the liver where it is stored as glycogen. However, the liver can only store a certain amount of glycogen, so when the glycogen storage area is full, the excess glucose is then converted and stored in the liver as fat. Unlike glycogen, it seems that the liver can store almost unlimited amounts of fat. This would appear to be a bit of a design flaw because, when the liver becomes overrun by fat, it begins to leak glucose from the glycogen storage area. As we have read, insulin works in the liver a bit like a tap, which regulates the flow of glucose from the glycogen stores in the liver into the bloodstream in a very controlled way. However, imagine the increased pressure in those stores as a result of being squeezed by fat all around them. The tap cannot contain the pressure and the glucose leaks out and into the blood.

So, despite higher insulin levels, the glucose level in the blood increases still further. This leads to the pancreas producing more insulin, leading to more fat being stored in the liver, until eventually the body needs to find other storage areas for excess fat, including the pancreas. And just as a liver full of fat cannot work properly, a fat-filled pancreas can no longer produce insulin. And all the time the glucose in the blood increases until it passes the level for prediabetes and eventually reaches the level to diagnose type 2 diabetes. This process is shown in Figure 2.

Figure 2: How type 2 diabetes develops

We saw earlier that the diagnosis of prediabetes and type 2 diabetes depends on the glucose in the blood reaching a certain level. But you can see from the above that it is clear the problem starts long before glucose levels reach the level to diagnose type 2 diabetes – or even prediabetes. This highlights how type 2 diabetes is not primarily a glucose disorder. We now understand that the main problem is with insulin, and specifically insulin resistance. This leads to high insulin levels in the bloodstream, something which can contribute to the development of high blood pressure and cholesterol levels, as well as high blood glucose levels. The implications of these changes will be discussed in Chapter 3.

Polycystic ovary syndrome (PCOS)

Another common condition associated with insulin resistance is polycystic ovary syndrome (PCOS). The WHO estimates that it affects over 3 per cent of women worldwide; other studies suggest that up to 18 per cent of women may be affected, many without having been diagnosed.

PCOS is usually diagnosed in young women and the main features are irregular or no periods, excess body or facial hair, having acne and being overweight or obese. In many cases, the ovaries are found to contain many small cysts (hence the name), although these are the result of the condition, and not its cause. It is likely that the main cause is high insulin levels, which then also affect the hormones that control the release of an egg (ovulation) each month and regular menstruation. These effects can result in infertility, weight gain and too much androgen (male sex hormones) being produced, causing excess body hair growth. Women with PCOS are at increased risk of developing type 2 diabetes in later life, although some develop prediabetes or type 2 diabetes as early as their teens.

PCOS is usually diagnosed in young women in their teenage years or twenties. It is easy to understand how the various problems it can cause can be very upsetting at this time of life. Treatments are directed at correcting the hormonal imbalance and encouraging weight loss. In my experience, many women with PCOS find it very difficult to lose weight, and I think this is for a number of reasons. Firstly, it can be because they don’t feel very good about themselves, and such low self-esteem is a real barrier to making lifestyle changes; secondly, the effects of PCOS in itself can often lead to depression, which can drive unhealthy ‘comfort’ eating. Finally, and perhaps most importantly, the high insulin levels actually make it very difficult for people to lose weight, especially if they follow a standard low-fat, high-carbohydrate diet that just stimulates yet more insulin to be produced.

Metformin is a treatment for type 2 diabetes that reduces insulin resistance and can be very effective in restoring regular periods, and a low-glycaemic-index diet (i.e. avoiding highly refined carbohydrates) has also been shown to be beneficial. Individuals who are able to lose weight will often find that their periods return as their hormones re-establish a normal balance. It is therefore important to be aware that fertility can return very quickly after starting metformin or changing diet.

Other conditions related to insulin resistance

Insulin resistance is now recognized to contribute to the development of a whole host of conditions. These include fatty liver, dementia, anxiety, depression, some cancers, gout, osteoarthritis, inflammation, heart disease, stroke, high blood pressure and high cholesterol levels. The bad news is that this means that these conditions are more frequent in people with type 2 diabetes and prediabetes. The really good news, however, is that changes you make to reverse the diabetes disease process will also help to reverse insulin resistance and lead to improvements in some of these other conditions.

CHAPTER 3

The implications of a diagnosis of type 2 diabetes

This chapter is in two parts. In the first part, I will set out some of the immediate health implications of a diagnosis of type 2 diabetes. Whether you already have type 2 diabetes, or have prediabetes, the aim is to ensure that you are fully informed about what having type 2 diabetes can mean for your health in the short term. It is not to alarm you, but to reassure you by explaining why you might have a particular symptom or health problem, and importantly to explain what you can do to minimize the impact of diabetes on your health, both more immediately and in the longer term.

The second part of the chapter will cover the different long-term complications of diabetes. Again, the aim is to provide an explanation of why these complications occur, reassurance that they are not inevitable and information about what you can do to minimize the risk of them occurring.

This chapter is included early in the book, as the information may help you refine some of the changes you want to make, in respect of addressing your diabetes or prediabetes.

The immediate health implications of diabetes

In Chapter 2, we learnt how high glucose levels in the bloodstream cause the typical symptoms of diabetes, such as thirst, excessive urination and blurred vision. We also learnt that many people never experience these symptoms, as they are diagnosed before their glucose levels become high enough to result in them. However, having diabetes or prediabetes can also be associated with a number of other, less marked, symptoms that may have crept up gradually over a number of years. Despite being less obvious, they may still have a significant impact on overall wellbeing and health.