The Diet Myth

So I’ve recently been on a well-earned break to Dubai and decided to read one of the most talked about food health books in the last 4 years, ‘The Diet Myth’ written by Tim Spector, a Professor of Genetic Epidemiology at King’s College London and Hon Consultant Physician at Guy’s and St Thomas’ Hospital. Having published over 700 academic papers in which a large proportion relate to nutrition and the cause of obesity and the lead investigator of the British Gut Project at King’s College London, I thought I would see what Professor Spector has to say about the ever increasing epidemic of obesity. This issue is not just affecting the US and the UK, but is rising rapidly in Asia and the Gulf States with Mexico leading the way as having the fastest growing obesity issue in the World.


Microbes are invisible to the naked eye and we have 100 trillion of them living happily in our gut weighing in around 4 pounds. They are primitive forms of life and only a fraction of the millions of species are harmful to us. Most are crucial to our health. They control the calories we absorb, digest our food, provide vital enzymes and vitamins and keep our immune system healthy. It is a mutually beneficial arrangement between our bodies and the microbes that keep all of us living in harmony. Think of it as an internal city in our gut or as Tim Spector calls a floral microbial garden.


Now I’m an advocate of counting calories when it comes to losing excess weight. It is a proven formula that I have successfully adopted for my clients over many years. Eventually, my clients understand the amount of food required to keep a certain weight. I am also a follower of consuming natural organic foods and ensure my clients have a healthy balanced thoroughly nutritional diet that keeps them feeling satisfied and full. Certain types of food are recommended to ensure that fullness is achieved without eating ‘dangerous calories’ such as energy drinks, protein shakes and processed foods which are definitely banned or heavily restricted.

However, Tim Spector is not all together a fan of calorie counting and says that much of our weight issues are down to the microbes in our gut. This intrigued me. He excepts at a basic level that a calorie is a calorie, but it is more. A calorie is defined as the energy needed to extract the food type (protein, carbohydrate, fat) and the energy produced which will be identical. The book argues that the formulas used are over 100 years old and are based on averages in a non average world, and errors in this method have been documented. The energy from food varies greatly depending on how much you chew your food, the foods you mix and the source of the food. It also depends on your genetic make-up and the microbes in your gut. This is where the book gets interesting.

Diet Myths

Tim Spector’s The Diet Myth explores the myth of dieting and through his own research experience and using further research conducted over many decades, has concluded that we do not all respond to food in the same way. He believes that the ‘obsession with the limited view of nutrition and weight as calories-in versus calories-out is unhelpful and distracting’. His fascinating detailed knowledge and experience through various controlled scientific laboratory research using identical twins with identical gene pools and laboratory rats has completely opened my mind to think further about the my own diet and the advice I give to my clients.

Our bodies are completely different. You often know a person who’s diet is not healthy but they are lean and yet the same diet can play havoc with someone else’s weight and health. This is all down to our microbiome flora in our guts. Our micrbiomes protects us from invading germs, breaks down food to release energy and produces vitamins for our bodies to work. There are the good bacteria guys in our gut. The main ones are Firmicutes, Bacteroidetes, Actinobacteria and Protoebacteria and there are bad guys such as the well-known Salmonella and E-Coli. Keeping our good guys healthy and strong will support our immune system and help us stay fit and healthy. By understanding what is good and bad for our gut flora may contribute to better health, more energy and a slimmer waistline.

Weight Loss and Gut Health

So how does our gut microbes affect weight loss. The majority of my clients come to me to lose weight. They have tried numerous unsuccessful diets beforehand and have committed hours of exercise to no avail. The Keto Diet, Paleo Diet, Atkins Diet, Vegan Diet, Vegetarian Diet, South Beach Diet, Raw Food Diet, Gluten-free Diet, Low-fat Diet, Fruitarianism Diet, 5:2 Diet or 16:8 Diet (intermittent fasting) and many more. Many of my clients had previously been to slimming groups and initially lost the weight only to put it straight back on.

By understanding our microbes are unique, we can start to understand why some people lose weight on these diets, and some don’t. However, one major fact that all of the research agrees with is eating a diet high in sugar and processed foods are bad for our microbes and consuming a food rich in vegetables and fruits are good for the gut flora. By diversifying our food, we take in more good microbes to help and enrich our gut garden of microbes.

Professor Tim Spector advocates a Mediterranean Diet, with the emphasis on plant foods, olive oil, fish, poultry, beans, grains, natural yoghurts, red wine (one glass per day) and natural cheeses to enhance your microbium gut garden.


Including prebiotic foods such as pulses, oats, asparagus, garlic, onions and nuts promote metabolic and digestive health and can help reduce inflammation and play a role in reducing insulin levels and cholesterol. These fibrous foods found in fruits (bananas), vegetables (leeks and onions, garlic, asparagus) and whole grains (whole wheat flour) are important for increasing healthy gut bacteria like Bifidobacterium. Galactooligosaccharides are the most advance form of prebiotics which belong to a particular group of nutrient fibres that feed and encourage good bacteria in the gut to fight off the growth of pathogens (disease causing bacteria), regulate the immune system and aid in digestion. A prebiotic is a non digestible carbohydrate that acts as foods for the good guys in your gut.


Polyphenols which are found in blueberries, red wine, dark chocolate, extra virgin / cold-pressed olive oil and green tea. Polyphenols are phytochemicals and have anti-oxidant properties which combat cell damage, boost insulin sensitivity and may lower risk of Type 2 Diabetes. There has been animal research that show green tea polyphenols can reduce inflammation and human research in the US has shown that extra virgin olive oil has high levels of Lignans polyphenols which can also reduce inflammation and therefore lower the risk of heart disease and cancer. Just don’t cook with olive oil (probably best to avoid cooking with olive oil as it alters it’s chemical structure and destroys phytochemicals). Use it on your salads, cold. Cocoa polyphenols found in dark chocolate can lower blood pressure and decrease LDL (bad cholesterol) levels.


Eat probiotic foods such as natural yoghurt to increase the abundance of healthy gut microbes and try to buy organic versions of all foods to eliminate the amount of pesticide and antibiotic consumption which play havoc with your gut flora. Probiotics are bacteria found in foods that keep your gut healthy. Common bacteria examples of probiotics are Lactobacillus and Bifidobacterium. They occur naturally in yoghurts and fermented foods. An imbalance in healthy bacteria in the gut may be linked to Ulcerative Colitis, Irritable Bowel Syndrome (IBS), Celiac Disease, Crohn’s Disease as well as Type 1 and Type 2 Diabetes. An imbalance is called dysbiosis.


TMAO (trimethylamine N-oxide), a gut bacteria by-product is formed during digestion of choline, lecithin and carnitine, nutrients that are found in animal products such as red meat and liver. By eating too much red meat (as oppose to white meat), TMAO levels rise and circulate and the production of TMAO by the gut microbes reduces the kidneys function to expel it. These high levels of TMAO has been linked to the development of atherosclerosis and heart disease. High levels of TMAO can show people at risk of stroke or heart attack.

You should consider reducing red meat consumption to once or twice a week and ensure that you eatĀ organic meats and wild fish to limited your intake of antibiotics fed to livestock.

Exercise and Stress

Exercise to reduce stress and increase higher levels of butyrate, a short-chain fatty acid that is very good for overall health and higher levels of Akkermansia, a bacteria shown to have a major role in metabolic health and the prevention of obesity. Stress is a natural occurrence and in small doses, very good for us. However, long spells of stress can have a detrimental affect on reducing Lactobacilli, a good bacteria in our gut.

A recent study from San Francisco State University showed that cardiovascular exercise and higher fitness level participants had higher firmicutes-to-bacteroids presence in the gut. Firmicutes are the bacteria that are associated with the metabolic process that helps prevent bacteria from the gut leaking into the body (leaky gut syndrome). Leaky gut is undigested food leaking through the GI tract into the bloodstream and causing inflammation.

So if you’re a weight-lifting purist, you may want to consider some cardiovascular exercise in your programme to enhance the health of your gut.



Studies have shown that sleep deprivation can have a negative affect on your gut flora. Sleep apnea can be caused by high cortisol levels in the body. Research on sleep and gut health is patchy at the moment but a study by scientists in Japan on students preparing for an exam taking a probiotic (Lactobaccilus type) drink daily for 8 weeks pre exam and 3 weeks post exam showed both groups experienced stress. However, as the exam day approached, the probiotic group didn’t suffer the same negative changes to sleep as the placebo group. The probiotic group fell asleep sooner, had deeper sleeps and felt more rested and refreshed.

These findings show that there may be benefits to ensuring that your microbiome remains healthy if you want to improve your sleep patterns and pass your exams.

Intermittent Fasting (IF)

I’m a follower of intermittent fasting (IF). I fast every day for

16 hours and feed during an 8 hour window. This allows my digestive system to rest and recover and therefore encourages my gut microbes to clean up my intestine wall and keep it healthy. It’s not as bad as you may think as 8 of the 16 hours is fasted asleep. Basically, I miss breakfast and am a 2 meal per day man.

IF is beneficial for your microbiome in many ways. Firstly, it gives your overworked microbes and digestive system a break from the processes involved in digesting food. In 2006, a French study reported in American Diabetes Association showed that postprandial endotoxemia was reduced which is found to increase the risk of obesity and insulin resistance through IF. In addition, it can improve the composition of your microbes. It is also reported to improve our gut bacteria due to circadian rhythm (our internal body clock). Many of our microbes are active at different times because they have a circadian rhythm. Eating late at night or at different times due to jet lag may
have a negative impact on our metabolic health.

There are different ways to IF but the two most commonly known are the 5:2 diet which restricts calories to 25% of daily allowance for 2 days and normal for the other 5 days. The other is the 16:8 where you eat during an 8 hour period everyday and fast for 16 hours.


The Diet Myth’s message is to change the way we think about our food and our gut health. For me, as a personal trainer, I find the book intuitive, informative and supported. It has opened my eyes to the fact that everyone is different with unique gut microbes and that is why diets often fail. Our bodies react differently. I will still hold the belief of calorie counting, but I also understand that some of my clients will struggle with weight on certain foods due to their gut flora and genes. By diversifying food and encouraging organic natural produce whilst restricting the intake of high sugar and processed foods, I can help and support my clients to live a happier healthier leaner life.

The Diet Myth has energised me to think about exercise and how exercise programming can affect people differently. The ‘one size fits all’ description is just as untrue for exercise prescription as it is for food. There is research currently being studied on the different affects of endurance exercise and interval training on subjects. Most importantly, some research has suggested that the wrong type of exercise prescription can lead to people becoming unhealthy. Sounds very familiar to me.