April 19

The Digestive System: The Missing Link to Achieving Great Results


By Wilde Performance

‘You are what you eat’ is only partly true. A more accurate way to describe it is ‘you are what you eat, digest, absorb and don’t excrete’.

In the modern western world we rush around, eat poor quality processed food, don’t sleep enough and stress about everything.

This has a hugely negative impact on many of the systems of the human body including the digestive system.

The aim of this article is to outline what the digestive system is, why it so important, what can go wrong and take a brief look at how to repair it when s*** hits the fan (pun clearly intended!). 

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The Hard Hitting Facts

Before we jump into the more complex areas, it is worth looking at some statistics and why the digestive system is so important to achieve optimal function. 

In 2007 the British Society of Gastroenterology commissioned a systematic review, that was intended to draw together the evidence needed to fill the void created by the absence of a national framework or guidance for service provision for the management of patients with gastrointestinal and hepatic disorders.

When looking at the following facts, please consider that many of the figures are from 2004 and secondly, that many cases of symptoms or disease go unreported by people. 

  • About 1 in 6 admissions to hospital are for the primary diagnosis of gastrointestinal disease
  • 1 in 6 main surgical procedures carried out in a hospital are carried out on the digestive system
  • Dyspepsia (describes pain or discomfort in the upper GI tract) symptoms typically affect between 20 and 40% of the UK population, depending on the diagnostic criteria used

The digestive system is an extremely important system, this is not to say that other systems in the human body are not as important but often clients find the greatest improvement in health and performance when they optimise digestion and absorption of food. 

Here are a couple of facts as to why we believe digestion should achieve more attention that what it currently does. 

#1. The human digestive tract has as many neurons as the entire spinal cord 

#2. All neurotransmitters that have been found in the brain are also found in the digestive system 

#3. There are more bacteria in the gut than there are cells in the body – bacteria help you survive, synthesise vitamin K and metabolise food 

#4. 75% of the body’s immunity is found in and around the digestive system 

What's Is The Digestive System & How Does It Function

The digestive system can be viewed as the barrier between you and the outside world. While food is in the digestive system it is technically still ‘outside’ the body. It is the only system in the human body that can work completely independently of any other system.

To keep it relatively simple, the digestive system is comprised of the brain, mouth, oesophagus, stomach, small intestine and large intestine. The digestive tract also receives help from the liver, which secretes bile to emulsify fat and the pancreas that secretes enzymes to help the breakdown of protein, fats and carbohydrates.

It is important to understand the separate parts of the digestive system and how they interact so that when an issue arises is can be effectively identified and corrected.

Many people consider the mouth, or maybe the stomach, to be the first stage of initiating digestion. However when you consider physiology we soon find out that the brain – thinking about food – will be what initiates the mouth to secrete saliva and enzymes into the mouth.

Let us side step for a second to enforce the above point: close your eyes and visualise a food you really enjoy whether it be cake or berries or maybe a steak, it really doesn’t matter. Now, visualise that object - how appetising it looks, imagine the texture on your tongue, how it tastes, we could go on. However, the chances are when you do this exercise you will start salivating, therefore it is a clear indicator that how we perceive food plays a significant role in initiating digestion. 

So we have established that the brain is what initiates the digestive process, now it’s the responsibility of the mouth to do two primary things:

a) Mastication (increases the surface area of food)

b) Start the breakdown of carbohydrates via amylase being secreted from the salivary glands

Food then travels down the oesophagus aided by peristalsis to then enter the stomach where the next stage of digestion occurs. It is important to realise that the stomach is mainly a digestive organ and very few things are absorbed in it.

The exception to this will be vitamin B12, alcohol and things like aspirin. Protein is the main macronutrient that is digested in the stomach. This occurs via the activation of the pro-enzyme pepsinogen, which is converted to active enzyme – pepsin. This requires adequate amounts of HCl (hydrochloric acid) to do so.

HCl secretion into the stomach via the cell walls is also important because it helps to signal to the rest of the digestive system to ‘get ready’. The stomach churns the food to try to further increase the surface area.

HCl is also crucial in order to sterilise our food. As a note, the stomach is the only part of the digestive system to have 3 layers of muscle where the rest of the system has 2 layers.

Food usually stays in the stomach for anything between 1-3 hours. This will largely depend on the size of meal, macronutrient density & level of stomach acid to name just a few variables. Food is then released into the first section of the small intestine, the duodenum.

It is here that protein digestion is finished, fats are being digested and where carbohydrate digestion is also completed. To be able to fully break down fats into free fatty acids, bile is required from the liver and the gallbladder to first emulsify fats before the lipase enzyme secreted by the pancreas can further break them down.

The pancreas is also responsible for secreting enzymes that further break down protein and carbohydrates (protease and amylase) – this very much simplified to avoid confusion. The final working role of the pancreas with regards to digestion is to secrete bicarbonate to neutralize the acidic chime (liquid mixture of food and digestive juices) that is released from the stomach. It is known that the small intestine has a relatively neutral PH.

As the digested food - in an ideal situation food molecules – glucose (from carbohydrate breakdown), amino acids (from protein breakdown) & fatty acids (from fat breakdown) pass through the small intestine aided by peristalsis, villi and microvilli (folds and projections inside the small intestine) help to further increase surface area.

This will in turn aid better absorption of nutrients into the body, therefore allowing the body to perform better at a cellular level.

Also, on the microvilli you will find what are called the brush borders which:

a) Further increase surface area

b) Secrete brush border enzymes to ensure all macronutrients are fully broken down to their simplest forms and food does not pass undigested into the body.

Optimal time for food to be broken down and absorbed in the small intestine is around 2 hours.

The remains of the digestive process then pass into the large intestine (colon) in a semi liquid form. The main function of the large intestine is to dehydrate it and form a more solid stool. Minimal absorption occurs in the large intestine. The only notable absorption will be water and electrolytes.

Worth noting is that the colon runs on short chain fatty acids that are produced by the degeneration of, but non absorption of, starch and resistant starch (fibre). The short chain fatty acids include butyrate, acetate & propionate.

There are no absolutes here but it is considered that 10-12 hours is the average time that food spends in the large intestine before being excreted.

What Can Go Wrong

As explained, the brain is responsible for initiating digestion. In the modern world we are constantly rushing. We rarely take time to sit and embrace the food that is in front of us.

When we rush, we usually don’t take the time to chew our food either, which can lead to less surface area being achieved in the mouth, thus the stomach acid will have less area to work with, resulting in the small intestine having to work harder to achieve total breakdown of food & absorption of nutrients.

It may sound obvious but the simplest way to improve your digestion would be to chew your food more.

In the mouth you do not usually find many problems, however a lack of saliva is certainly one, thus no initiation of the initial carbohydrate breakdown. As mentioned above not chewing our food properly and swallowing large lumps is a disfunction of sorts.

Finally, a coating or bio film on the tongue can be a good indicator of bacterial imbalance further down the digestive tract.

The most common issue with digestion that we see in clients is low stomach acid levels. If stomach acid levels are low then the ability to break down protein is reduced.

Also your ability to sterilize the bacteria in the food you eat is compromised. This could lead to infection (H Pylori, parasites), bacterial imbalance (dysbiosis) and/or yeast or fungal overgrowth.

To side step: Many people in the UK currently suffer with acid reflux symptoms, which they go to the doctor with and are prescribed proton pump inhibitors (antacids).

This will lower stomach acid even further, which in turn will open up the body to potential infection and malabsorption of protein.

It is very possible to have acid reflux symptoms with low stomach acid. While the food is being churned in the stomach, if the oesophageal sphincter is not functioning correctly then it can stay open and allow acid to flow up the oesophagus and present symptoms of acid reflux. 

A much more likely cause of acid reflux in many people is low stomach acid, thus meaning food remains in the stomach too long, keeping the sphincter open.

Also if people experience issues with the nervous system then the oesophageal sphincter might not operate optimally, thus allowing the flow of acid up the oesophagus.

There are many areas of potential deficiencies and issues that can occur in the small intestine. However, the main problems will include the following:

  • Not enough bile being produced by the liver to emulsify fats, thus leading to malabsorption and potential fatty acid deficiency. 
  • Damage to villi and microvilli will lead to less surface area being achieved, which in turn will lead to reduced breakdown of food and less absorption of nutrients. Also, damage to the very fragile microvilli will mean that important brush border enzymes will not be released to activate pro-enzymes and avoid undigested particles of food entering the blood stream (gut permeability).
  • Pancreatic enzymes could not be released and/or activated due to damage or dysfunction of the pancreas.

The large intestines will usually only experience 2 areas of disfunction, one being dysbiosis (imbalance of good to bad bacteria) of the bacteria and the other – transit time is disturbed. Increased transit time can lead to potential re-absorption of toxins or hormones that were to be excreted. 

If the transit time is significantly reduced however, we are at risk of not only not digesting our food properly but also not absorbing the vital nutrients. In alternative medicine a good transit time is considered to be around 12-16 hours. An hour either side is nothing to worry about of course, but extremes at either end would require further investigation. 

Above we have very much outlined how the physiology of the digestive system can become dysfunctional. It is worth mentioning that infections, deficiencies and disease will all come as a result of disfunctional physiology. Of course there are people with genetic pre-disposal but in truth they make up a tiny percentage of the world’s population. We always like to say ‘Genetics load the gun and lifestyle pulls the trigger’. 

An Introduction To How To Fix The Digestive System

It is extremely important to treat each client as an individual and tailor an approach to the specific issue. Below we have outlined the ‘four R’s’ protocol that we use with clients to help them achieve optimal digestion and absorption of nutrients. 


The remove phase considers looking at any potential bacteria, infection or food allergies and intolerances. This can be achieved by using a strategic elimination diet to remove potential food allergens. The next step would be to send a client for testing. A few tests to consider are stool analysis with parasitology, breath test for intestinal bacteria overgrowth and gut permeability testing.

There are certain protocols to help remove pathogenic bacteria/yeast from the digestion but this is beyond the scope of this article. 


Replace stage is based around correcting deficiencies in digestion – mainly HCL supplementation and digestive enzymes. HCL supplementation will help with protein breakdown in the stomach thus improving absorption further down in the GI tract.

And supplementing with enzymes will further help with breakdown of foods, allowing for greater absorption of vital nutrients. 


Repair stage focuses on addressing the damage to the digestive tract. Again, it is way beyond the scope of the article to list specific protocols but essentially you need to look at healing all areas, as if one part of the digestive system is affected it is often the case that much of the system will also suffer to a certain degree.

The good news is that cells of the digestive system repair relatively quickly (days/weeks) compared to say the bones, which take much longer. 


This stage focuses on repopulating the gut with good bacteria. This is where probiotics come in. We find that this is what most people do first. However, for us this is back to front.

For instance if there is a deficiency in stomach acid we already know that you will a) not be digesting protein properly and b) the food you eat will not be sterilized adequately, therefore if pathogenic bacteria are making it past the stomach, probiotics will only be masking symptoms and when stopped you’re likely to find yourself back at square one.

People often feel better when taking probiotics but it is not unusual for symptoms to return after they discontinue use. It is extremely important to address the above issues before we try to re-inoculate the large intestine. 


To summarise, the digestive system is extremely important to achieve optimal function whether day-to-day life or sports performance is considered.

This is not to say it is more important than for example blood glucose management or adrenal function, but we find people making the greatest improvements in health when they can:

a) Digest food properly and

b) Absorb nutrients into the body that will ensure various systems of the body can work optimally.

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References & Further Reading


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