Why do you overeat? – Zoë Harcombe

Introduction

We’ve got a break from dissecting academic papers this week as it is almost 20 years to the day since my first book was published. It was called “Why do you overeat? When all you want is to be slim” and it was launched at the London Book Fair on 15th March 2004. The photo shows the cover back then. The book was revised and republished at the end of 2012 (Ref 1). I could have written the book many years earlier than I did. I’ll close this note by sharing how it came to be written.

My first interest in anything food related started when my brother, Adrian, developed type 1 diabetes. He was 15 and I was 13. I witnessed him drop 20 pounds in as many days. Looking back, the diagnosis took unnecessarily long. The characteristics of being a teenager, dramatic weight loss and insatiable thirst should have been so obvious, but this was years ago, and diabetes was not constantly in the news as it is now.

When Adrian was admitted to hospital, we were given a family training session to understand the difference between a state of hypoglycaemia (low blood glucose levels) vs. hyperglycaemia (high blood glucose levels). As soon as Adrian came home, I helped my big brother inject insulin into his body and started to make the obvious connection between insulin, carbohydrate and weight.

The family diet changed overnight – gone were the high teas, with scones and cake, from my parents’ upbringing and in came ‘meat and two veg’ kind of meals. The dietary advice for diabetics then was not too bad. It deteriorated over the years, as first the Balance of Good Health plate was introduced and then the ‘Eatwell’ plate and then the ‘Eatwell’ guide (Ref 2).

Later in my teenage years came the next issue to stimulate my interest in food. I was at a Corpus Christi college, Cambridge University reunion the weekend of 8th March 2024, and I sat next to a medic who was in her final year. We had a fascinating conversation about how things had changed since I was at Corpus. One thing that we realised had not changed was high achieving women having troublesome relationships with food. My medic friend also observed that men have body pressures now, similar but different to women, which were not apparent in my day. While women seem to want to take up as little space as possible, men are trying to bulk up. She noted that men are spending hours in the gym trying to achieve a ‘ripped’ look and they are often consuming excess protein, which is where she comes in as a medic – dealing with the consequences of extreme examples of this.

I was junior president of the college in my final year. In the year before that I was women’s officer. Each college had a women’s officer – Corpus just didn’t start this tradition until they realised (in 1983/4) that women should be admitted to the college. It had only taken them since 1352 to do this!

Being a college women’s officer involved dealing with issues that might affect women at the college level and collaborating with other college women’s officers at the university level. At a college level I achieved changes to formal invitations to include dress codes for women. The invites used to say, “White tie”, “Black tie”, or “Lounge suit.” The women had not a clue what to wear. Corpus soon had white tie/ball gown, black tie/cocktail dress, lounge suit/day dress – not too challenging for the organisers and hugely valued by young women who never know what to wear at the best of times.

The university women’s officer role involved (I’m sorry to say) making rape alarms and self defence classes available. We didn’t have traceable transport apps or simple ways to text/call to say we were home safely. The university also provided information on eating disorders. There were only 20 women in my year at Corpus. I remember reading the information and thinking “a lot of that applies to me.” I thought I was the only person trying to control my eating, overeating at times, getting scared at the thought of these enormous ‘super hall’ dinners we so frequently had. Cambridge life seemed to revolve around food. I put a note in the pigeonholes of my fellow female students saying that I had this information and, if anyone wanted to borrow it, I was in room 12KP or I could leave it in their pigeonhole if they wanted to remain anonymous. Virtually every women in my year came to see me. It was such a relief for all of us that we knew we weren’t the only ones having trouble with food.

It was while at Cambridge that I found myself becoming addicted to certain foods. It was never the lobster bisque and rack of lamb at these posh dinners. It was the breads and cakes at Fitzbillies patisserie – cruelly within a stone’s throw of Corpus (and still there). It was also the sweets and crisps in the newsagents opposite Corpus. This was when I first started to ask the question – why am I doing this? I’m more than half bright. So, why do I overeat when all I want is to be slim?

Why do we overeat?

When I set out to try to understand why I couldn’t stop eating when I wanted more than anything to be slim, there was no internet and research was nowhere near as easy as it is now. I trotted off to book shops and libraries and looked for anything that seemed to provide a lead. This, and some unique personal experiences, led me to discover three physical conditions that cause food cravings. Why do you overeat? also explored the psychological reasons for our attraction to food, but there are strong physical drivers. If we don’t overcome these, no amount of counselling will improve our relationships with food.

Food Intolerance

My first breakthrough was going to a great GP (General Practitioner/family doctor) while I was at Cambridge. He was a young doctor, and he may have been clued up on the latest thinking as a result. I had been to GPs before about feeling out of control around food and they just wanted to refer me to a counsellor. I found counsellors pretty useless to be honest. They were either obese or skeletal – so not the role models I was looking for – and none could explain why I only wanted certain foods. They all wanted to explore different psychological strands and I just wanted to get the heck out of the room, so that I could eat a box of chocolates!

This GP was different and wonderful. I took in a written list of symptoms – bloating, gaining or losing pounds literally overnight, insatiable cravings, mood swings, energy highs and lows etc and he didn’t even mention a need for a counsellor. He referred me instead to the Food Intolerance centre of excellence in the UK, which just happened to be based in Cambridge. What luck.

I went along and was given a skin prick kind of test, but, more importantly, I was asked about what I most craved and least wanted to give up. I saw Dr Jonathan Brostoff personally, who was the UK expert on Food Intolerance at the time and may still be (Ref 3). I was put on an exclusion diet where I was allowed meat, fish, vegetables, salads and not much else for the first couple of weeks and then I had to return to the clinic for more foods to be added in. I remember losing about 10 pounds in a fortnight, but, even more astonishing for me was that I just completely changed into a different person overnight. It was almost indescribable – but some of you will know what I’m talking about, having experienced the same by ditching junk, for real food. I remember my skin being so clear and my hair shiny and everyone commenting on how well I looked. I was allowed back on fruit and whole grains quite quickly but told to stay off dairy for some time (not sure I needed to, to be honest; I had never craved dairy of any kind).

Bingo, I thought. That’s me sorted for life. I love Dr Brostoff. However, I didn’t realise at the time that there were two other pieces to the jigsaw. I replaced sugary stuff with fruit (sugar in a different form) and I got to the point that I was eating dried fruit (mostly medjool dates) by the pound, grapes by the pound, cherries by the bucket load – an obscene amount of fruit. All of this I thought was super healthy, of course, as so many people still believe today. By the time I was 25 and living and working in London, I was a complete sugar addict. The sugar had come back into my diet, and I seemed powerless to overcome cravings for sweets and chocolate. Even cakes and biscuits, which I had not eaten for years, were calling out to me and I couldn’t say no.

Hypoglycaemia

This was the start of probably the scariest period of my life-relationship with food. I started passing out with blood glucose lows. The worst time was on the London Underground and I came round with a kind lady looking after me on the bench on the platform, but who knows what could have happened to me or my belongings. Because of my brother being diabetic, I was continually tested for diabetes and the tests were always negative. Looking back, if I had not sorted this out, I would probably have been type 2 diabetic by the age of 30.

I went to two GPs during this time – one wanted to refer me to a counsellor again – she was extremely dismissive and unhelpful. The other one said if I felt faint, I just needed to eat a Mars Bar®. Great – and then feel faint again 90 minutes later and gain weight during the process. I asked the second GP to send me for a glucose tolerance test – something I had heard about while reading as widely as I could. I passed out approximately 60 minutes into the glucose tolerance test and the daft doctor still suggested that I live on Mars Bars.

That was probably my first realisation that the medical profession does not always know best, and I took my health into my own hands. I was fortunately travelling to the USA a lot with work at the time and the USA turned out to be years ahead of the UK in health matters. I tended to be alone in any rare free time I had, so I loved wandering around shopping malls where they had coffee shops in bookstores. I would spend an evening drinking milky coffees and reading books – bliss.

One evening I came across a self-help medical section and a particular book screamed out at me: “Hypoglycaemia: The disease your doctor won’t treat” by Saunders and Ross (Ref 4). When I flicked through the symptoms listed in the introduction my jaw was on the floor. I couldn’t believe that someone had written a book that so described what I was going through. I bought that book and Carlton Frederick’s “New low blood sugar and you” (Ref 5) and devoured every word.

The clear explanations of how I had been messing up my insulin mechanism and making things worse made sense and the symptoms were all there. The solution was scary because of my sugar and fruit addiction. I actually found it easier to go cold turkey on sugar, than fruit. I had a deeply held view that fruit is healthy and so I must eat it.

The recommended diet was very similar to the original Food Intolerance diet I undertook while at Cambridge, but I don’t think I made that connection at the time. I tried and failed the diet many times – my addictions ran deep and there were no support groups or testimonials to encourage me. I confess that my success in staying off foods high in fake or natural sugar was not high during my mid-20s.

Candida

The final breakthrough came while reading a magazine on nutrition at the age of about 27 and seeing a nutritionist write about yeast infections. I thought that she was just talking about thrush and thought little more about it. Then, browsing through a Holland & Barrett book stand one day, another book jumped out to talk to me. It was the Leon Chaitow classic “Candida Albicans: Could yeast be your problem?” (Ref 6). The front of the book listed “irritability, bloatedness, heartburn, tiredness, allergies, cystitis, menstrual problems” and I suddenly realised Candida wasn’t just about thrush. I tracked down the nutritionist in the article and arranged a phone consultation straight away.

This Chaitow discovery was the final piece in the jigsaw for me. I took the book home, and it was like a light bulb moment. In the chapters on Candida, Food Intolerance and Hypoglycaemia in Why do you overeat?, I list all of these early works as recommended reading (Ref 7). They are not out of date. They were absolute trailblazers and should still be admired and read today. I treasure the originals of these books, as they literally changed my life.

I remember one weekend in my flat in London. I laid out all the books on the living room floor and searched for passages that I had skimmed over at the time. I remember reading one bit in a book on Hypoglycaemia about “your get up and go has got up and gone” and bursting into tears – that had been a great description of my 20’s thus far.

Time to be a mathematician – I got a pad of paper and started to write down the symptoms of each of the conditions, the causes of each of the conditions and the recommended diet for each of the conditions and the similarities were just startling.

There were passages in the books just here and there – if you didn’t read the book thoroughly you might miss them. They turned out to be the inspiration behind Why do you overeat? They captured in the most raw and real way what doctors were seeing when they were treating the three conditions – Candida, Food Intolerance and Hypoglycaemia. The comments on the first two of those three conditions particularly were dynamite. I share them all in the chapters on Candida and Food Intolerance and they will resonate with any food addict. The pioneering doctors, who wrote those early works on these little known ailments, had the answer to the Why do you overeat? question. From the perspective of the particular condition in which they had expertise, they would have been able to explain why their patients had insatiable food cravings, felt addicted to food and were overweight or obese. They had the answer to the million dollar question and didn’t realise the potential of their work.

Phase 1

On more bits of paper I started to pull together the perfect diet for each of the conditions. Mathematicians will understand this as – a search for the lowest common denominator for all three conditions. This became known as Phase 1 of the diet that I first presented in Why do you overeat?

The most challenging condition was Candida, as the advice for this varied quite a bit between the experts writing at the time. I summarised where each doctor stood on different food groups – all of the different views are summarised in the Candida chapter.

Some judgments were easy, as part of the process to try to establish ‘the perfect diet’ for all three conditions:

– Did they all allow real meat? Yes. Processed meat? No. So real meat is in, and processed meat is out. The same outcome held for real fish vs. processed fish.

Some judgments were slightly more complicated:

– Did they all allow eggs? Yes, but with a caveat for Food Intolerance that, if someone has craved eggs and may think they are intolerant to them, they should leave them out. Hence eggs are allowed in Phase 1 with the note about the person needing to be honest if they have craved them.

Fruit was one of the most difficult decisions:

– Fruit was allowed freely for Food Intolerance; not allowed freely for Hypoglycaemia and not allowed for some time in the Candida diets. I decided that Phase 1, ‘the perfect diet’, should have no fruit, as fruit was not deemed OK for two of the conditions. It was clear that Candida needed to be the driver for when fruit was re-introduced. (Hypoglycaemia is also an important consideration in the fruit decision, but Candida is the most important condition).

Thus Phase 1 of what later became known as “The Harcombe Diet®” was born. The length of Phase 1 was determined by Food Intolerance. Food passes through us in approximately four days, so, at five days, the substances to which we are intolerant should no longer be in our systems and the cravings should be massively reduced. I tried it and they were. Bingo! This has been confirmed by many people since. Hypoglycaemia can be hugely helped in just one day. We start to stabilise blood glucose levels the minute we stop eating processed carbohydrates and dramatically reduce carbohydrates generally. Candida is the one condition that is not ‘fixed’ within five days and people may need to stay on Phase 1 longer to really zap this horrible parasite. If I’m honest, another driver for the length of Phase 1 was that I was a huge fruit addict at the time and, personally, I couldn’t bear the thought of being ‘off fruit’ for more than a few days. No wonder – fruit sugar was feeding my Candida beautifully.

I look back now and smile because no one was writing about these conditions 20 years ago. Wind forward to today and food sensitivities, blood glucose fluctuations and gut flora are mainstream. Heck we even have walk-in food intolerance testing, continuous glucose monitors and the Zoe app wants you to send your poo away for microbiome analysis!

Phase 2

Phase 2, what to eat after five days, was a similar mathematical exercise. It was partly driven by Phase 1 – what are we already eating and what might we be able to add back into the diet for nutrients and variety. The second key driver was, having been on every diet under the sun, it was relatively easy to compile a list of criteria that the perfect diet would need to meet. The five that I thought were critical were:

1) It must work – and not just in the short term. It must help us reach our natural weight and stay there.

2) It must be practical – a real diet for the real world. No working out grams of protein or counting calories or carbohydrates – some simple rules that we can follow at home, at work or eating out, as part of our busy lifestyle.

3) It must be something we can follow for life – a real lifestyle change – something we can stick to easily and not something we go on and then go off leading to lifelong weight fluctuations.

4) It must be healthy – and deliver the nutrients we need for healthy living.

5) It must be enjoyable – and not take away eating as a pleasure in life.

That was my check list. You may have your own.

Phase 2 came about from wanting to condense these principles of a lifelong way of eating into as short and simple a list as possible. Phase 2 was thus based on three rules:

1) Don’t eat processed foods (I later changed that to “eat real food” to put it as a positive).

2) Don’t eat fats and carbs at the same meal.

3) Don’t eat any foods that you currently crave (Ref 8).

The first rule was easy. We have evolved to eat real food and we have to return to eating real food. I believe that modern illness (diabetes, cancer, heart disease etc) would be massively helped, if not avoided, by eating real food, as nature provides it.

The second rule developed from connections that I made when I first started to study nutrition. The connections between macronutrients, insulin and weight loss had been at the back of my mind since Adrian developed diabetes. The first observation was that protein is in everything – with just two exceptions: oils and sucrose. Lettuce, apples, bread, pulses – as well as the obvious meat, fish, eggs and dairy products etc – all contain protein. From this it follows that, food is a combination of fat and protein or carbohydrate and protein. Since protein is in everything, we can then just abbreviate the fat/protein to fat and the carb/protein to carb.

The key distinction between the two groups is those that have an impact on glucose (prompting insulin) (carbs/protein) and those that don’t (fat/protein). Back to my brother. When Adrian first developed diabetes, the only thing that changed in his body, in effect, was that he stopped producing insulin. No insulin meant no ability to store fat. A type 1 diabetic will lose sugar (calories) in the urine until the condition is diagnosed, but these excreted calories cannot explain the dramatic weight loss that occurs before the diabetes is managed under medical supervision. A key observation that must be made is the massive impact that insulin has on weight. Once people start injecting insulin, they struggle to stay at a normal weight for life. Adrian has done really well in this respect, but I think it’s because he’s a great ‘cook from scratch’ chef and has always only eaten real food.

When you study nutrition (and I mean study – not what you’re taught at school, if anything), you learn how the body digests food and uses food for energy. Then you realise that the minute the body sees a carb it will use that for energy first – it’s the easiest food to break down into glucose. The body is also keen to save some fuel for later on (we are evolutionarily hard wired to store food). It wants to store fat, ideally. So then you realise that, if we eat a ham sandwich, the body wants to use the carbs in the bread for immediate energy, and it wants to store the fat in the ham for later on. It can only store fat if insulin is present. And – insulin is present because we just ate a carb. Perfect – we have helped the body to store fat by eating carbs at the same time. Great for a caveman – not so good for a 21st century slimmer. So it just seemed obvious not to eat the two macronutrients together.

Another observation to support rule two was that, while nature provides carb/proteins or fat/proteins, rarely are carbs, fat and protein present in the same real food. Nuts and seeds are the exceptions. I find nuts irresistible and ‘more-ish’ – because of that carb/fat combo. The fake food manufacturers have realised this and all fake food is a carb/fat combo – cookies, cakes, ice cream, chips, crisps, chocolate, donuts, croissants, pastries, desserts etc – they all have that carb/fat combo, and we find them irresistible and ‘more-ish.’ If I let you have butter on its own, you have a limit. If I let you have crackers on their own, you have a limit. Put butter and crackers together and you have no limit. Many people lose weight simply by following the ‘no mixing’ rule. This rule guides people to have ‘fat’ meals (steak/salad) or ‘carb’ meals (veggie curry and rice). People soon realise that the ‘fat’ meals are more satiating and better for weight loss. Many people thus consume more ‘fat’ meals and became naturally low carb in doing so.

The final Phase 2 rule reflects the unique findings of Why do you overeat? That there are three conditions that cause food cravings and how to eat to overcome these, so that food addiction can be kept at bay for life. Phase 2 teaches people how to become an expert in recognising the condition(s) from which they might be suffering and how to avoid the particular foods that feed those conditions. Manage the conditions and the cravings manage themselves.

Phase 3

Phase 3 is also based on three rules (with many other tips): 1)  Don’t ‘cheat’ too much; 2) Don’t ‘cheat’ too often; 3)     Be alert and stay in control. Cheating is having something outside Phase 2 rules. We deliberately call it a cheat, not a treat. Thinking of junk as a treat needs to stop.

Phase 3 has been a revelation to me. When I first started trying to work out a diet that would get me slim and keep me there for life, I loved the idea that I might be able to eat biscuits, crisps, cakes, chocolates again and be able to eat them without feeling addicted.

I confess that I slipped up quite a few times moving between Phase 2 and Phase 3. I cheated too much, too often and on things that were far too processed. Hence the guidelines that are shared in Phase 3 – eat the things with the fewest processed ingredients: crisps with just potatoes and sunflower oil, not Pringles® that have 20 horrific ingredients in them. Dark chocolate with cocoa, cocoa butter, vanilla and a tiny bit of sugar – not milk chocolate, which is essentially sugar, powdered milk and other processed stuff. I came to realise that, whereas my weight used to determine what I ate – now the main determinant of what I eat by a margin is how I feel. I know that I could cheat on cheap chocolates and get away with it (weight-wise), but the thought makes me feel sick. I would never be that horrible to myself again.

It is natural for people to start Phase 1 dreaming of how quickly they can get back to eating the food(s) that they currently crave. Most people find that once they get to the weight and eating pattern that they desire, they no longer want any of these foods again. They are not treats; they are punishment. The realisation that I would get to the point where I despised the foods to which I was once addicted has been the biggest overall shock to me throughout this whole journey.

From helping me to helping others

The final part in the story is dedicated to Earl Lynch. Indeed, the book was dedicated to Earl. Earl is an incredible motivational speaker and facilitator/trainer like no other. Earl is the reason that there was ever a first book…

I was the Human Resources (HR) Director for the Welsh Development Agency from 2002-2005 and had the most wonderful team working with me. We went on a team building session in the summer of 2003 and Earl was our trainer. We had laughter, tears and bonded in a way some of you may understand, if you have been on similar sessions with work or community clubs.

At the end of the session we buddied up and made a promise to our buddy about something we had always longed to do but had never gotten round to. I was teamed up with “Sian”, a young HR trainee destined for HR manager and more. Sian said that she was going to get fit for the first time in her life, as she was ashamed that she got puffed out running for a bus. I said that I would love to write a book to help other people addicted to food, but I would try to think of something more achievable because I would never do that. Earl happened to be passing our seats as I said that. Like any great facilitator, he intervened. “What’s stopping you?” he gently asked. “Time”, I said “I would never get the time to write a book.” Earl then said, “I’ve heard you guys all talking about Big Brother – you seem to have the time to watch that…” and then he walked away.

Talk about hitting home. I thought about all the time I wasted doing things that were really of no value in my life. I then committed to Sian that I would write the book.

That August, my husband, Andy, and I went on the first two week holiday that we had had. Instead of taking the usual half a dozen light-reading books, I took a laptop. I decided whenever I would normally read, I would write instead. In the totally inspirational surroundings of beaches and palm trees in St Lucia, I wrote the bulk of the original version of Why do you overeat? I was so motivated; I spent the autumn getting up at 5am to write for two hours before heading off to work. I finished the manuscript over the winter holidays and the book was launched at the London Book Fair on 15th March 2004. The first copy off the press went to my buddy Sian, who, by then, was as fit as a fiddle.

I put my email address in the first edition of the first book – thinking that about 20 people would read it. Hundreds of emails later I realised that people were losing several pounds in Phase 1 and then going on to lose several more in Phase 2 and keeping this weight loss off.

One woman wrote to me: “Where were you when I was stuffing my face at college?” And I replied – “probably doing the same thing!” That’s when I realised that I may not be an HR Director for much longer.

References

Ref 1: Zoë Harcombe. Why do you overeat? When all you want is to be slim. 2012. https://www.amazon.co.uk/Why-Overeat-When-Want-Slim/dp/1907797246
Many of the books referenced below have many editions, as they were so popular. Don’t be too troubled by the dates below – online book sites will have many versions – some just a few pence/cents.
Ref 2: https://www.zoeharcombe.com/2016/03/eatwell-guide/
Ref 3: Professor (Dr) Jonathan Brostoff & Linda Gamlin. The Complete Guide to Food Allergy and Intolerance. 4th edition. 2008.
First published in 1989, this book has remained the widely acknowledged `gold standard’ in the field of food allergy and intolerance.

Ref 4: Jeraldine Saunders & Harvey M. Ross. Hypoglycemia: The Disease Your Doctor Won’t Treat. 1980.

Ref 5: Carlton Fredericks. New Low Blood Sugar and You: The Startling Facts of How Millions of People Suffer from Hypoglycemia (Low Blood Sugar) without Knowing it – The Simple Diet That Can Completely Eliminate This Disease. 1985.

Ref 6: Leon Chaitow. Candida Albicans: Could Yeast be Your Problem. 1985.

Ref 7: Classics in addition to the ones referenced above:
Shirley Lorenzani. Candida – a Twentieth Century Disease. 1986.
Dr John Parks Trowbridge and Morton Walker D.P.M. The Yeast Syndrome. 1986.
Dr William Crook. The Yeast Connection. 1983.
Martin & Rona. The Complete Candida Yeast Guidebook. 2000.
Gill Jacobs. Beat Candida. 1990.
Robert Buist. Food Intolerance – What it is & how to cope with it. 1984.
Dr Marshall Mandell and Lynne Scanlon. 5-day Allergy Relief System. 1979.
Dr Keith Mumby. The Allergy Handbook. 1988.
Dr Theron Randolph & Dr Ralph W. Moss. Allergies – Your Hidden Enemy? 1981.
Dr Richard Mackarness. Not all in the Mind. 1976.
Dr Elson M Haas & Cameron Stauth. The False Fat Diet. 2001.
Martin L Budd. Low Blood glucose (Hypoglycaemia) The twentieth century Epidemic? 1983.
Ref 8: Please note that these are three rules for a weight loss plan. My general rules for how everyone should eat (not specifically to lose weight) can be found here: https://www.zoeharcombe.com/2021/08/what-should-we-eat/