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The Diet Myth: The Real Science Behind What We Eat

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Fully updated throughout and with a new foreword for this edition.

Why do most diets fail? Why does one person eat a certain meal and gain weight, while another eating the same meal loses pounds? Why, despite all the advice about what to eat, are we all still getting fatter?

The answers are much more surprising - and fascinating - than we've been led to believe. The key to health and weight loss lies not in the latest fad diet, nor even in the simple mantra of 'eat less, exercise more', but in the microbes already inside us.

Drawing on the latest science and his own pioneering research, Professor Tim Spector demystifies the common misconceptions about fat, calories, vitamins and nutrients. Only by understanding what makes our own personal microbes tick can we overcome the confusion of modern nutrition, and achieve a healthy gut and a healthy body.

419 pages, Kindle Edition

First published September 8, 2015

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About the author

Tim Spector

27 books266 followers
Tim Spector is Professor of Genetic Epidemiology at Kings College, London and Director of the TwinsUK Registry, which is one of the worlds richest data collections on 11,000 twins. He trained as a physician with a career in research, which since 1992 has demonstrated the genetic basis of a wide range of common diseases, previously thought to be mainly due to ageing and environment. Most recently his group have found over 400 novel genes in over 30 diseases, such as osteoporosis, osteoarthritis, melanoma, baldness, and longevity. He has published over 600 research articles in prestigious journals including Science and Nature. He coordinates many worldwide genetic consortia and is currently at the forefront of research with a highly competitive European Research Council Senior Investigator award to study Epigenetics – a new exciting research area into how genes can be altered. He is the author of several books for the scientific and public communities and presents regularly in the media.

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Displaying 1 - 30 of 315 reviews
Profile Image for Trevor.
1,301 reviews22k followers
February 16, 2021
This book is, unsurprisingly, given the title, about the pointlessness of most diets. Well, sort of. His actual problem isn’t so much that diets don’t work – although, you know, diets don’t work – but rather that diets almost invariably get you to do what is likely to be the exact opposite of what you ought to do. That is, like the cabbage diet or the banana diet or the paleo diet or the keto diet or the ice cream diet – diets are often basically about limiting either the amount of food you eat, or, more frequently, the types of foods you eat.

Don’t eat fat. Don’t eat carbs. Don’t eat sugar. Don’t eat grains. Don’t eat meat. Stop eating this one food and supermodels will jump into bed with you – click the link below this article to find out just which that food is…

But the real take away from this book is that what has happened to us over the last few decades is that we have rushed towards a huge restriction in the variety of foods that we eat. The problem with that is that our gut biome flourishes if it has variety. In some cases we have reduced what we eat to insanely few items in various guises – corn, beef, wheat, milk, alcohol, chicken – and all of it processed and attacked in various ways to ensure it is clean and pure and bland and dull. The bugs in our guts aren’t fooled, though – those that haven’t died off go to war with us and our bodies.

I’m really not a nutritionist, I’m not trained in any of this stuff. But his arguments seem to make sense to me in that they encourage us to eat a variety of real foods. You would need to work quite hard to convince me that I would be better off if I started to eat pretend food over real food, or that pretend food will be somehow be better for me. At one point in this he talks about comparing the diversity of bacteria in the shit of hunter-gatherer populations compared to those of us inflicted with a western diet. Hmm. The lack of gut bacteria in those eating a western diet is disturbing.

I liked this book a lot. He goes through various diets and explains the logic behind why people think their particular favourite ought to work and then he explains why they mostly don’t. Food really ought to be so central to how we live, but we rarely treat it with anything approaching respect. Which is a very strange thing, when you think about it.
Profile Image for Margaret.
Author 20 books84 followers
November 8, 2015
It isn't very often I come across a book that I would consider a life changing experience. This book is definitely one of those.

Tim Spector's very readable and explains the science behind what we eat, why diets don't always work, and exactly how our digestive system works.

I came away from this book with a deep understanding of why some foods don't sit well in my stomach, a starter's guide to tailoring the way I eat for my body's needs, a deep distrust of refined sugar, and an enormous respect for my own personal microbes.

I have great respect for Tim Spector. He admits he's made mistakes as a scientist. It takes a big man to admit to his mistakes, and an even bigger one to do it in writing!

I cannot recommend this book highly enough to anyone interested in how their body works, in eating well, and staying healthy. A rare 5 stars from me.
Profile Image for Holly.
1,012 reviews226 followers
December 10, 2015
This is not about diets as in weight-loss - it's about diet as in nutrition. And another book about the gut microbiome by a Brit. (The UK is on this!)

I've read too many of these books this year and they are starting to blend together. (Giulia Enders' Gut does stand out though). What made Spector's book interesting was its broad scope (he covers everything I've read this year) and its particular quirkiness: he outright admits that much of his early career research was wrong because it was either based on faulty assumptions or conducted with inadequate research methods (e.g. the famous study that suggested that coffee caused pancreatic cancer). Related: his willingness to look stupid in the midst of his erudition. This tone is used sparingly enough to be amusing:
I once tried Tuscan remedy for cold prevention. At the first symptoms you take three cloves of raw garlic and a full bottle of Chianti. The results were amazing. The next day I woke up with garlic breath, a bad hangover and the predictable cold symptoms. I later was told I should have taken it before getting the cold.
Profile Image for Sue.
2,729 reviews220 followers
June 16, 2015
I've been struggling to loose weight for some time and have lost over 130 pounds. But lately itsvslowed down to me going up and down the scales. My GP recommended this book as she had ordered it too. She is great at keeping up with the latest concepts. I agreed to read it. It was a very enlightening book! Some of the things you think are 'healthy foods' can turn out to not do you any favours at all. I knew about super foods and processed foods so that came as no surprise however there were loads of things in here that is well worth you purchasing this and one clicking.

This is not some gimmick book this has been written by a very respected Professor
Profile Image for timv.
295 reviews6 followers
March 2, 2021
The author repeatedly points out the invalidity of large observational health studies and anecdotal evidence in nutrition science, which is a very valid point. However, He then uses anecdotal stories, conjecture, and speculation to push forward his opinions. This was not one of my favorite books on the human microbiome. It is packed full of information and speculation, though.
Profile Image for Kyle Nicholas.
138 reviews19 followers
November 27, 2015
Where to begin?


Okay, hysterical rant over. Now for the more reasoned critique.

This book is as formulaic in its approach to "mythbusting" as the quasi-religious dietary tomes he proposes to bust. The formula goes something like this:

1. Premise - I have the one true and right answer for why we (meaning not me but all you suckers) are fat, sick and miserable. I alone have the one ultimate truth, and I'm about to liberate you from old notions of what it means to be ill... nay, even to be human!
2. You should listen to me because I am a doctor! or a scientist! or a dietician! or an unspecified specialist in some way! or a doctor of some field not even remotely related to nutrition! or a journalist (only interested in protecting YOUR interests, not just mine, by the way!) or a former fat/sick person who stumbled onto this miracle cure while cleaning out my mother's garage!
3. You shouldn't listen to all those other advice books because... [here insert reason, being that the authors are shills for Big Pharma, Big Diets, Big Vitamin, Big Organic, Big Frankenfood, etc.]
4. Now for my explanation.... but first!
- Talk about ancient human origins.
- Discuss why premodern societies were so great.
- Elaborate on how everything dramatically changed sometime around the French Revolution/Industrial Revolution/World War II.
- This establishes why you're sick and fat. This also covers the bulk of the book, about 75%.
5. Point to some research that confirms your hypothesis. Downplay any hypocrisy, naturalistic fallacies, anecdotal evidence or bias by using weasley words and possibly skeptical-sounding language and attitudes because you know that consumers are too stupid to know any better. After all, this is why they fell for your book in the first place.
6. Reveal miracle cure in the final pages of the book. Remind readers that everything they know from conventional wisdom is wrong because it's been a big conspiracy all along. Add obligatory legalese you were forced to include at gunpoint so your publisher doesn't get sued about listening to your doctor... even though she's in on the conspiracy, too, and shouldn't be trusted.
7. Profit.
8. Retire in the manner you prefer because a lifetime of "honest" work won't fully pay for those international vacations, expensive artisanal yogurts, wines, cheeses and anal-swabbings by themselves. Only book royalties and designer niche products you will now market will.

This guy has the audacity to try to pass this work off as "skeptical" because he poo-poos homeopahty (pun fully intended. I've never met anyone so thoroughly in love with his own feces [!] since I broke up with an ex-boyfriend who was a certified narcissist!)

I can save you gentle readers the time and expense of reading this slop-bucket of a tome by summing up basically as he did: You are fat, tired, and miserable. You are screwed. This is not necessarily because of anything you did... after all, the self-help market is flooded with feel-good don't-blame-yourselves victimhood. It is because your parents, obstetrician, pediatrician, doctors and society made a lot of well-meaning but BIG mistakes. So... fly to France. Find the dirtiest rural dairy where they roll cheese in cow turds before setting it in a cave for six years. Partake of expensive mold, wine, garlic and bullshit. Live long and prosper... as a fat, miserable idiot.

Finally, this. A four-pound turd. In Africa. This is what we should all be aiming for, people! A close second would be this book.

(EDIT: To make your book more credible, be sure to harp on how developed, non-Anglophonic nations are doing so much better than we are. Especially everyone's sweethearts Sweden, Norway, Holland, and Japan. Why? Because they all regularly have fun in the dirt, eat moldy cheese or weird seaweed, and are the healthiest, longest-lived people in the world! And conveniently forget that in regards to Japan, the healthiest of all nations, its citizens are also the most germophobic in the world.)
Profile Image for Петър Стойков.
Author 2 books282 followers
February 27, 2023
Книгата прави много добро описание на различните видове диети и начини на хранене, които са популярни в момента. Описва ги многостранно, без предубеденост, като отчита техните предимства и недостатъци, съобразно резултатите от проведени диетични и медицински изследвания. Една от най-добрите страни на книгата е, че описва и съществуващите масови заблуди относно тези хранителни режими от страна на лекарите, които далеч невинаги са наясно с научните доказателства по въпроса.

Също така, авторът има доста реалистичен поглед върху самите изследвания на различните диети и начини на хранене и отчита техните слаби страни по отношение на научния метод (повечето от тях са просто сравнителни изследвания, с данни, събрани с въпросници, които са доста далеч от научния "златен стандарт" на двойно слепи експерименти).

В края обаче, Тим Спектър не дава никакъв извод, различен от безпомощното "от всичко по малко" и "не прекалявай с нищо" с което се задоволява всеки, който няма достатъчно време/възможност да се запознае с науката по въпроса и е притиснат от безкрайното количество различни, противоречащи си твърдения в тази област.

Все пак, ако искате балансиран, обективен преглед на различните начини на хранене и диети - от палео до веганизъм, това е книгата.
Profile Image for Janet Berkman.
405 reviews32 followers
March 4, 2016
This is a terrific book, with the perfect balance of case histories and literature reviews on the topics covered. Spector is a British genetic epidemiologist and physician who, among other things, has done a lot of twin studies. Published in 2015, the book includes the latest research in the microbiome in its evaluation of the components of our diet, and the rules (good or bad) that we've been living with around food. Spector takes a hard look at the evidence for lots of things and comes up with some surprising (to many) conclusions. It is very readable and I highly recommend it to anyone interested in improving their health through what goes into their bodies (food, supplements, medicines, alcohol, caffeine....)

I had many take-aways from this book. I want to radically increase the variety in my diet (even though I already eat a pretty healthy spectrum of food) to include more prebiotic foods. Also, I plan to switch to mainly wine and beer from distilled spirits (better for the gut.) I also plan to add in some dark chocolate.
Profile Image for Mohammed H.
69 reviews4 followers
January 4, 2017
One of the best books you will read about food. I have tried so many diets and failed miserably. I understand now that my gut needs variation of different foods. Why do some diets work for some and don't work for others! Read and you will find out. Every diet you heard of is probably discussed in length. This is a must read if your health is important to you. Its not only informative but also written with great sense of humor. I like how he describes the gut as being your garden and the microbes in your gut the soil in the garden. Its a very enjoyable read with a lot of knowledge.
Profile Image for H.A. Leuschel.
Author 5 books256 followers
August 23, 2020
A fantastic book because it's well written, clear and deeply informative! I urge you to read it before considering trying any type of diet!
Profile Image for Boy Blue.
462 reviews72 followers
April 4, 2020
There is a huge amount of information in this book and that's great. Spector doesn't want to start another diet cult so doesn't really prescribe a particular diet to follow. Rather he looks to create a paradigm shift in the way we look at our diet and how our body responds to it. His view is that our microbiome (all the stuff living in our gut, mostly bacteria) combined with our genetic makeup decides how we put on weight and how healthy we are. He supports the theory with his two pillars; twin studies (studies of identical twins), and studies on mice.

His theory is best summed up by Michael Pollan's saying "Eat food, not too much, mostly plants."

In addition to this Spector identifies a few extra habits and features of a healthy diet. Namely, the Mediterranean diet is the best well-known diet to follow. All other diets fall into the trap of narrowing your food source too much and putting too much dependence on particular items. This creates imbalances and a narrow range of gut flora when you want balance from diversity. You should try and eat as many different fruits and vegetables as you can (swear I've heard that before). Spector's big on olive oil (extra virgin) and nuts, the former slightly more than the latter. He also highly rates prebiotics, namely, Jerusalem artichoke hearts, chicory, garlic, onions, celery. These get to your large intestine because of the large amount of fibre. But he says the jury is out on probiotics and they probably don't work. Although yoghurt, proper cheese and fermented stuff is great. Ok with a glass of red wine. Dark chocolate seems good too. Milk makes us tall across generations. Better to be born vaginally and if you aren't you need your mother's healthy microbes swiped over your face immediately. Fasting is good for a few reasons, it seems to promote serotonin creation and also stimulate the good microbes in the gut when paired with a diverse diet.

Junk food not good for you. SURPRISE! But it's mostly because of the way it reduces your microbiome diversity. Exercise does little to nothing in the fight against weight. Reducing calories right down helps a lot but is almost impossible to achieve long-term outside a hospital or the army. After a month or so your body will dial your energy consumption down and fight you to stay fat. It does something similar when you exercise. The benefits from exercise aren't really weight related but more towards cardiovascular health etc. Antibiotics are really not great for your microbiome for obvious reason but are particularly damaging at a young age. Artificial sweeteners through a complex process actually end up making you fatter. This process involves the reduction of your gut diversity and somehow improving the uptake of carbohydrates and starch to energy. 

I would have liked to see the exploration of the transfer of microbes between people living and working together. Of particular note was, Mary, a woman who at the age of 35 divorced her husband went on a holiday to India, took some broad spectrum antibiotics while there and when she returned she was essentially lactose intolerant. While her twin sister never displayed the Lactose intolerance I would argue that Mary had a good microbiome from living with her husband and when she stopped living with him she was no longer receiving that cross pollination.

Here are an array of what I thought were the most interesting facts if they're lumped together it's because that's how they were in the book.

- Twin studies show that the twin that rigorously diets ends up being heavier over time. 
- Our bodies always adapt to reduced calorie intake. The dull monotony of exclusion style diets is overidden by the body's impulse to hold onto fat stores.
- Once someone has been obese for awhile a whole series of biological changes transpire to maintain or increase their fat storage and the brain's reward mechanisms for food. This is why most diets fail.
- If you reduce daily calorie intakes of people/patients to 1000 calories (rdi is 2000-2600) then they will definitely lose weight. But this is really only possible in a controlled environment like a hospital or in the army. The other option that works is Gastric Bypass Surgery but this remains unpopular even after 50 years.
- Our gut microbes/ microbiome are more likely to responsible for our physical condition weight wise over anything else.
- Most of the microbes we have are in our large intestine (the Colon). This absorbs most of the water. The small intestine is where most of the food and energy is absorbed. Food usually gets to the small intestine having been chopped up by our teeth and aided in digestion by the enzymes in our saliva and stomach. The small intestine also contains microbes but we know less about them than the large intestine. High Fibre foods make it to the large intestine because they need more time to break down.
- Sterile mice delivered by c-section with no microbes will not grow well and will be runts. If you give sterile mice normal microbes after a few weeks they still never develop normally, they do better if they start life with normal microbes which are then largely eradicated by antibiotics, although never healthy they'll do better than the first group. They do best if they start life with normal microbes and don't have them wiped out.
- If you give a mouse a pregnant woman's stool sample they will get fat and much bigger than if they are given a non-pregnant woman's sample.
- The more diverse your microbiome and by necessity your diet the better. 
- Humans used to eat about 150 different foods in a week. We now eat about twenty. 
- Intermittent fasting can stimulate friendly microbes but only if it is paired with a diverse diet when not fasting.
- If you look at the microbes in a subway station in New York they'll match closely the citizens living in that city.

- Calories aren't all the same. A study done where one group had 17% of their total diet based on natural vegetable oils and the other group 17% trans fat, saw the trans fat group getting much fatter, three times the visceral (harmful) belly fat. This is despite the calories being the same. A CALORIE IS NOT A CALORIE
- Not to mention the huge inaccuracy of many food labels. Manufacturers are allowed 20% margin of error but many frozen food items are out by up to 70%. Something as simple as almonds is often mislabelled with about a 30% error in calories.

- People who lose their sense of taste don't get fat.
- There might be a sixth taste called kokumi "heartiness"
- Taste buds aren't in areas but evenly spread across the tongue, they regenerate every ten days.
- 1931 a Dupont chemist created a chemical called PROP which 50% of people found bitter 20% intensely unpleasant and 30% couldn't taste it at all. Such difference between individuals.
- TAS1R and TAS2R are the two major genes for taste.
- There are 3 gene variants for sweet tastes, five for umami, and at least 40 for bitter (toxins)

- Exercise barely helps and is not enough on it's own. Study of 12,000 runners over several years found that  however far participants ran they were fatter each year. The researchers suggested if you add an extra 4-6 kilometres to your weekly run total each year, you might, if lucky stay the same weight, but this would have you running upwards of 100km a week.
- Your body responds to intense exercise by trying to conserve energy, energy expenditure will drop by 30% in your rest periods if you are exercising regularly.
- Being fat and fit is definitely better for you than thin and unfit. Particularly from a heart disease and mortality rate perspective.

- Microbiome diversity was significantly higher in an elite group of Welsh rugby players than in average men. Their inflammatory markers were lower 

- Brain uses 20-25% of our daily energy resources.

- Cholesterol is a complex lipid that is part of nearly every cell in our body. 80% is naturally occuring in the body with only about 20% the amount we eat.
- Cheese supplements may maintain our microbiome when on a course of antibiotics. Unpasteurised hard cheese when given with antibiotics has been found to speed up recovery times and reduce bacterial resistance. 
- There seems to be no provable link between saturated fats and increased risk of heart disease.
- 40% reduction in the risk of becoming obese in a Spanish study of 8,000 when taking daily portion of yoghurt.

- Not a huge amount of evidence for probiotics being that effective so put down your Yakult! Although there are a few benefits, treating C. Diff, dealing with hypercholestoremia, increasing thiamine.

- Our genes to degree dictate which gut microbes will thrive in our bodies. But equally our diet over a period of time can through epigentic processes effect which genes are on and off.

- Red meat is red because of the protein myoglobin which is good for endurance. Something white meat doesn't have, hence why chickens can dash across the road but not run a marathon.

- Weston Price travelled the world in the early 1900's for 25 years, recording the eating habits of remote tribes and populations untouched by "modern degeneration". Most of these groups ate the liver, kidneys, heart, and intestines, gave away lean meat to their dogs etc. Inuits have few plant sources so seek out caribou and whale livers for vitamin c.

- Extra virgin olive oil very good for you. No real evidence showing that it becomes bad when used in cooking. 
- PREDIMED, 7,500 mediterraneans in Spain given a few different diets, already eating about 40% fat from meat, olive oil, nuts, dairy etc. Some were told to avoid fats, some told to eat extra nuts, some given an extra bottle of olive oil each week. Study was stopped because it wasn't ethical for the non fat group. Olive oil and nuts group had 30% less chance of heart attack, stroke, memory loss, and breast cancer. Extra olive oil group was also better at preventing diabetes.
- Olive oil seems to be able to switch of the genes through epigenetics for the inflammation in blood vessels that leads to heart disease. 
- Polyphenols the big hero here. Mop up toxins and seem to reduce inflammation. Olive oil has huge amounts of polyphenols, almonds too.
- Olive oil may have an advantage over other oils because it comes from the whole fruit not just the seed.

- Mice eat each other's poo which may be for the diversification and sharing of microbes. If you put a fat mouse with a lean mouse, the fat one will become lean over time not vice versa. Except in the instance where the mouse was fed a high fat/low fibre diet, then it would stay fat.
- Christensenella might be a miracle microbe. One in ten humans have it. When transplanted into mice on high fat diets it prevents them from getting fat. It also seems to prevent obesity in humans and prevent the accumulation of visceral fat.

- Liping Zhao has been running succesful dieting plans for millions of Chinese. His first most famous case was a 29 year old 175kg man. Zhao found an incredible amount of enterobacter in this man's body. It seemed to be bullying the other microbes and keeping him fat. Zhao took this enterobacter colony from 30% to 2%. Lost 30kg after 9 weeks, 51kg more after another 4 months. Also a diet of gruel, made up of natural Chinese ingredients, grains etc. 
- When implanted into sterile mice Enterobacter makes mice on high fat diets fat very quickly.

- Fewer than 1 in 6 dieters said they have managed to maintain a 10% weight loss for more than 12 months. 
- After a period of 6 weeks of intense dieting on any regime that has achieved a weight loss of more than 10%, energy expenditures and metabolism diminish so as to compensate as the body tries to regain its previous fat stores. This metabolic slowdown can be as much as 10% of daily calories. Low fat diets seem to produce the greatest effect on the resetting mechanism, high protein/low carbs the least.
- Keystone species include bifidobacteria, F. prausnitzii, lactobacillus, and the ancient methane produce methanobrevibacter.

- One species of bacteroidetes contains over 260 enzymes for breaking down plant structures, we have 30. Total gut microbes have 6000 different enzymes.
- At least 145 genes have been horizontally swapped to humans from other species
- Seaweed digestion is a classic example of this ability. Possibly swapped from a microbe like zobellia.
- Seaweed may aid in weight loss. 

- There is a clear correlation between milk consumption and height. 
- Americans were the tallest race in the world but they've been passed by the Dutch and their enormous milk consumption. 
- Only 35% of the world can drink a half pint of milk and not feel sick. This shoots up to 90% in Northern Europe
- With the help of the microbe lactobacillus Lactase enzyme breaks down lactose. This is turned off in babies once they start eating solids. Except for those who have the gene mutation. 

- Divide grams by 4 to get the number of teaspoons.
- Strep mutans is the microbe that creates cavities in our teeth by producing lactic acid, they do this while stuck to dental plaque.

- Most superfoods are just marketing bullshit. Almost all fruit and vegetables are superfoods
- Nothing works in isolation. e.g. carrot and spinach are great sources of carotene but this is best absorbed when olive oil is also present.

- Most coeliac sufferers gain weight once they get on a gluten free diet. 
- Amylase in our saliva to break down carbohydrates and in the pancreas for release into the small intestine. 
- Each copy of the amylase gene you are short of increases your chance of obesity by 19%
- Very hard to measure without incurring huge costs.

- Artificial sweetners may reduce your gut microbes and create a more acidic environment.
- They also seem to somehow increase the ability of your gut to absorb starch and carbs more effectively, which can ultimately leading to weight gain.
- Alkaline diet is stupid because your body controls your internal PH naturally and you shouldn't really shift it.
- In fact PPI (proton pump inhibitors) which are an anti-acid drug that helps with heartburn often causes infections in the intestines. 

- Most of the body's hormone serotonin is created in the intestines and is mainly manufactured during times when not eating.

- Flavonoids and polyphenols in chocolate good
- Studies show an increase in good cholesterol HDL from eating dark chocolate, regular chocolate eaters have healthier metabolisms and microbes than occasional eaters
- At least 70 percent cocoa is best.

- Asians carry a variant of the alcohol gene dehydrogenase which metabolises alcohol 50 times faster than europeans or africans

- Glass of red wine good. Alcohol in small amounts good. 

- 20% increase in food allergies and asthma in c-section babies. With a further sevenfold increase in risk of allergies if mother has an allergy herself.
- Risk of obesity increases by 20% if born by c-section and no good microbe swab to the face 

run out of space :(
Profile Image for Magdalena Golden.
203 reviews12 followers
May 25, 2019
I am very positively surprised by this book! I was a tad sceptical given its slightly sensationalist title but in the end decided to pick it up based on the author's qualifications as a practising genetic epidemiology researcher at Kings College London. Tim Spector's competence in the subject shines clearly through his measured tone, arguments based on cited scientific research, complete with discussion of each paper's methodology and avoidance of overgeneralising individual findings.

The central theme of the book is the importance of our gut bacteria and how they, together with our genetic make-up, make us react to food differently, yet with a few overarching common principles. These principles can be translated to some nutritional advice that, while for some might seem painfully common-sense, is refreshing in how it doesn't promise miracle shortcuts in an industry that is full of them. Spector succinctly summarises it as:

/* Spoiler alert ;) */

Try to eat a greater variety of foods, particularly fruits, olive oil, nuts, vegetables and pulses plus fibre and polyphenols. Avoid processed foods, anything that claims to be a special low-fat or light product or has too many ingredients, and reduce your meat intake. Eat traditional cheese and full-fat yoghurt, avoiding synthetic varieties. Try adding more variety of fermented foods to your diet like kefir, fermented cabbage or soy-based foods. I like the concept that our ancestors ate in very irregular and seasonal ways, so intermittent fasting or giving up meat for months at a time or skipping some meals seems sensible to enhance your perception of variety. Throughout the year try to eat fruits and vegetables that are in season so as to increase the diversity of the foods you consume. Also, cutting back on liquid calories, such as sugar in juices and other drinks, as well as calories in cakes and snacks, is sensible, as is avoiding artificial sweeteners as a regular alternative.

And while for some people reading this could potentially be enough, I strongly encourage you to read the entire book. It goes into a lot of detail on why exactly these are the final recommendations while being entirely devoid of fluff that often plagues books that could potentially be classified as self-help.

The study that was the biggest eye-opener for me was one of the first ones mentioned. It involved feeding people identical diets while not performing any exercise and found that over 2 months some participants gained 4kg while others 13kg. That's a threefold difference! I had obviously been aware of the fact that some people seem to be able to eat a fair amount of junk food and still stay lean while others seemingly put on weight by just smelling a bag of crisps but I was still stunned by how big the actual difference can be.

The only negative things I can say about this book are that:
1) while it is generally well-written, some transitions between paragraphs could have been made a little bit less jarring. Some more editorial work would have been useful here but this problem concerns only a handful of situations;
2) sometimes, especially at the beginning, it seemed to be that the author was overemphasising intrinsic differences between people. Saying e.g. that some difference was found to be 50% genetic and making it seem as though that meant that the person was doomed due to it, when to me it seemed like - hey, there's the other 50% that can be worked on. Having finished the book, though, and so looking at the data more holistically, I can understand better where he's coming from. Adding up all those differences in particular genetic or microbiotic aspects can truly produce huge differences in how susceptible people are to their environmental conditions.

Overall, this one definitely goes on my list of favourite books and I've already started to implement some of the suggestions to keep my microbes happy :)
Profile Image for Alex.
73 reviews32 followers
June 2, 2017
I wanted to like this book, as I was in the market for a book on how food affects the human microbiome, and in turn how our microbiome affects the human body. Even more so because I got this book as a gift, and free things are always better than things you pay for.

However this book will the first in my new policy of abandoning books that don't keep my attention locked to them. After reading 140 pages (just under half the book), I began to notice a theme playing out:

** Explain current dominant consensus > provide some preliminary evidence that the consensus is wrong or flawed > segue into pure conjecture about the cause and effect of microbiome diversity. **

This 1-2-3 write-by-numbers approach is evident by the third chapter, almost as if it was stuck on the writer's wall and he felt compelled to follow the pattern. Any discussion of the microbiome was full of words like 'could', 'might', 'probable', 'conceivably'. These are logical signposts of speculation or hypothesis, not evidenced conclusions. In a way I should have expected this, as the book cover itself plays to the same tune. The front cover doesn't mention the microbiome at all, but the blurb touts it backhandedly at the end of a paragraph, like an afterthought (much like it appears in the body text of the book).

A book on the author's field - genetics and twin studies - would have been a far more interesting read.
Profile Image for Cecilia Lindblad.
5 reviews5 followers
November 4, 2020
A very well wriiten book about our gut. The writer that has a good humour and that helps to digest ;) all the facts! I also appreciate that all facts are backed upp with studies and all of them have notes of reference.
Profile Image for Maxime Hons.
52 reviews
August 20, 2023
This was a very interesting book which gave me new insights about food and diet myths we all believe in. I was skeptical at first, because I thought this wouldn’t provide me with new insights since I have listened to podcasts about diet myths and the first few chapters were about subjects i already heard of before. After a while I gave up reading but since I have stomach issues I restarted it, hoping I would find some useful information for myself. I’m glad I continued because in the middle of the book it got a lot interesting for me, suggesting insights i do too falsely believe in. Also why have i never properly heard about the effects of microbes on our diet like hello? Why isn’t this common knowledge spread in biology class? I liked the tone of writing, with the occasional humour
and anecdotes that made it more digestible to read. Although there were a few chapters with a lot of medical information and therefore i had to reread a few sentences sometimes which slowed down the reading process for me. I do prefer reading books a bit faster but i did have to read this one slower over a month time because I just couldn’t read more than 2 chapters a day. Nonetheless I do recommend this book to anyone who wants to get a healthier relationship with food and diet.
Profile Image for Alicia Joy.
75 reviews
February 28, 2016
I will keep it simple - everyone needs to read this book. Microbes are the future of health, and understanding them may help motivate you to change your diet - not to diet, but to change what you eat.
8 reviews
February 9, 2017
Excellent. Very clear and backed up by the best science. A great rebuttal to all the shonky 'experts' out there and something you can rely on to guide your eating habits. I intend to look after my 'garden' - with a few naughty treats very now and then!
Profile Image for Catullus2.
164 reviews5 followers
March 21, 2021
An interesting read on the importance of one’s microbiome. Takeaway: avoid antibiotics unless essential, eat a wide variety of unprocessed food, avoid sugar, do less housework (yeah!), live with animals (double yeah!), try intermittent fasting.
Profile Image for Trâm.
184 reviews1 follower
May 10, 2021
3.5 stars // Genuinely makes me want to scrap processed food more than my mum's nagging probably will. Moreover, the 30 different plants thumb of rule is very helpful. Overall, the book seems properly cited but take this with a grain of salt, since I'm not a certified nutritionist (although the section on vitamin D could have used more nuances; in class we discussed that supplements do decrease bone fractures in the elderly which was not mentioned at all. Plus, he does refer to some anecdotal evidence, which is spotty.)
Profile Image for Shiny5711.
162 reviews
August 31, 2019
Three stars? Four stars? I think this book is worth a look-see, though to be fair I skimmed most of it. There was a lot of over-my-poor-head science in here. My advice is to grab this from your local library (don't forget about inter-library loans if your facility doesn't own it!) and read the Conclusion. THEN, if you have questions or your interest is peaked by something Dr. Spector says there, go back to that chapter to look into it more closely.
Profile Image for Indrė.
29 reviews4 followers
April 11, 2021
A well supported book with a serious science evidence. It was not a reductionism promoting book, thank god. I am now very sceptical for any food, diet books, but Tim Spector is a person who has rights to write books about food and microbes in the gut, not like many zealots aka 'biohackers' without a proper education and only personal 'eat only this for a month and you will lose weight forever' shit.
A book has personal details, but Tim has a lab where he has been conducting Twin studies, clinical trials for many years. Microbiome part was the most interesting part of this book and promoting to include variety of foods in the diet not to reduce(!) affecting your GI system. You can agree with this or not, it is personal because we react to food different ways, and without constant lab tests or blood draws you can only guess.
Not much new surprising things, but an easy long read.
68 reviews
December 31, 2020
Perhaps the most informed book I have read on what we eat that I have read and, thankfully, one that didn't have an axe to grind. This was simply a wide ranging review, backed up with a mass of research, of a series of myths surrounding diets. The common thread was viewing diet from the point of view of our microbiome, the bugs within us that symbiotically help us with digestion if we allow them to flourish. This ranges from the transfer of bacteria from the birth canal to some eyebrow raising procedures with poo. The style is authoratative but relaxed which makes for an easy read. In my world, I am currently being pressured to go low carb as a way of improving my endurance for triathlon (well I can hope) and it was disappointing that this diet was effectively bypassed as it wasn't a diet he'd tried or had any information on - better to have no information than wrong information I guess. In fact, it would have been preferable to have had a bit more guidance on what to eat rather than just dealing with the myths. This advice, such as it was, seemed to boil down to eat more variety, especially fruit and veg (shock!), stuff to promote your prokaryotic friends and less refined carb and processed food. Maybe that will be his next book.
1,747 reviews53 followers
November 3, 2017
This contains less information about microbes than I would've thought (and less than some other books about the microbiome/gut). The author also seems to cocky for his own good. He seems a bit dogmatic and too willing to bash diets without addressing the science they put forward. He also rarely backs up his claims with detailed studies. Although he will mention studies at high level he neither gives details, or discusses their short falls.

He says the paleo approach to nightshades and tomatoes in particular is laughable. He says that the tomato can't be viewed in a reductionist fashion only focusing on certain components. He then reductionistically says tomatoes are good solely based on its lutein content. Tomatoes are delicious and one of my favorite food so I am biased towards them. However, tomatoes are at least bad for me (I have problems with histamine). Tomatoes are also linked to GERD (I believe the relax the esophogeal sphincter, but I could be wrong). There are also many people with autoimmune disease who do better avoiding tomatoes. It is possible these people are suffering from nocebo, but in order to state that you should provide good evidence.

He states that vitamins are bad. This is a bit of a blanket statement. The vitamin A,E studies can be used to damn those vitamins and perhaps other antioxidants but such a blanket statement that vitamins are bad is dangerous. Personally I've had some vitamins give me bad results and some give me good ones (that Doctor's have been unable to provide). Most vitamins seem to do nothing and are only bad due to their cost. The author does not distinguish between synthetic and natural forms of vitamins (he seems to not be able to distinguish folate from folic acid).

It's not that this book is all bad, it did convince me to all but eliminate red meat (although I am not entirely convinced that's a good move it seems to be the less risky option). Most of this book is old hat and is certainly useful if you haven't read much recent news about diet or get your diet news from one echo chamber. That being said, I'd rather you read some good veggie books (Proteinaholic is the best I've found) and good paleo books (Chris Kresser is fairly unbiased) and form your own opinions.

I would expect better from a geneticist (I actually expected to see that the author was journal when I looked at his bio). I am not that familiar with genetics, but his statement that because some people have more amylase genes than others we are evolved enough that grains are a positive influence on our diet. I would assume that this merely proves that people evolve. I would assume that proving grains are good you would need to do at least a randomly selected, long term mortality study. This also ignores negative aspects of grains (low nutrient density, filling [e.g. replacing veggies], soil depleting)
Profile Image for vix.
1 review
February 4, 2020
I found this book disappointing. After a promising introduction, in which the author remarked how biased, unscientific and cult-like in their following most current approaches to diet and nutrition are, and how he proposed to get to the bottom of what actual scientific knowledge we have, I was fully onboard - that was exactly what I was after as well.
But then when he started to write about his research and conclusions, chapter after chapter was a disappointment - it seemed to me that this wasn't an unbiased book at all, just one based on his own biases.
As an example, it doesn't seem that he was interested in getting to the bottom of why vegetarians and vegans are on average healthier than meat eaters (at least in terms of metabolic diseases). Where the science on whether poultry is detrimental to our health was inconclusive, the author concluded that it is probably ok to continue to eat poultry. Where, despite his best efforts, he could not find a scientific base to the widely held idea that soy may have adverse effects on our health, he concluded that it's probably best to avoid soy and continue to do more research on it.
How is that an unbiased, dispassionate or science-based approach?
Profile Image for Salma.
8 reviews3 followers
January 18, 2020
This book does what is promised - to transcribe evidence on the most popular diets out there in manageable chunks and summarise what could be healthy versus what could harm our health rather than give a list of dos and don'ts (although if you want to skip the research and get the take home just read the "check-out" chapter in the end). The insight into how the microbiome plays a role in obesity is also really interesting. There are useful sum ups of the benefits of controversial claims about superfoods - that some foods like seaweed and spirulina claim to be healthy but our guts aren't necessarily adapted to derive benefit from them in the first place. And he debunks myths and clarifies questions I had about intermittent fasting, the FODMAP diet. I also have a new found appreciation for identical twins and how regularly they're asked to be involved in genetics research. Overall a good read if you're interested in an in depth understanding of what the research says on the relative benefits of food and diet but I would still have a look at some of the references and take some claims with a pinch of salt (pun intended).
889 reviews
April 15, 2016
A good overall review of the lack of solid evidence for much of today's dietary advice, including the role of fat & cholesterol in CV disease, the uselessness of vitamins & supplements except where there is a deficiency, the role of proteins , carbs & fibre. He also discusses artificial sweeteners, caffeine, alcohol, antibiotics, and the warnings re. potentially allergic components like peanuts.
Central to the discussion is the role of the intestinal microbiome & its role in extracting &modifying the effects of nutrients & controlling weight,as well as preventing allergy by producing a myriad of substances which have direct as well as epigenetic effects(turning genes on or off).
He advises a very varied Mediterranean diet rich in fruits & vegetables, in full fat dairy products including unsweetened yogurt containing probiotic bacteria, cheeses, whole grains, olive oil, nuts, wine, olives...& avoidance of manufactured & processed foods or "anything not recognizable as food to your grandmother's gut bacteria".
This entire review has been hidden because of spoilers.
Profile Image for Lydia Tevenan.
12 reviews
August 14, 2023
Life changing book for many people.
It’s all about diversity in your diet (and gut) and avoiding processed foods, something we all know. But, Tim Spector explains why, and how we can all improve our diet habits for longevity and happiness. Brilliant book, must read.
Profile Image for Kate Cooper.
9 reviews
January 7, 2021
An absolutely insightful book to read of which I have a personal interest in. Having made my own journey into gut health I’ve realised that as long as you are eating the right types of foods and a broad diversity, you really can eat more and lose weight. The chapters are sectioned into food groups and sub-sectioned again into further categories which are easy to digest (pardon the terrible pun). There’s a huge platter of interesting facts backed by credible research, and true stories which are certainly eye-opening. I was particular drawn into the chapters about vitamins and antibiotics. Definitely recommend for anyone interested in nutrition or looking to make changes to their diet.
Profile Image for Chris Lightfoot.
69 reviews
August 26, 2015
Every now and again, a book comes along that is some way, life changing. This is one. It's not a lecture. It's facts in a very readable way. Tim, the author carries a lot of credibility with his vast background. I throughly enjoyed this and will embrace some of the recommended changes as well as read again in the not too distant future.

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