Dr David Unwin 

Dr David Unwin
What does insulin do?

It’s a hormone that we produce that helps us deal with sugar. It is produced by the pancreas gland, and it deals with sugar. It pushes sugar from the bloodstream into cells, where you need sugar in your muscles for energy. But if you eat more sugar than you need for energy, insulin pushes excess sugar either into your belly fat or your liver. But what happens if that insulin does not work very well? Well, then the blood sugar levels, known as glucose, starts rising and you end up with a higher blood sugar level. And high blood sugar levels are dangerous, certainly over time it attaches to proteins in an irreversible way and starts damaging your circulation. It damages the small circulation in your eyes and your kidneys and over time damages your larger circulation in your arteries. And that’s why we worry about hearts and strokes with diabetes. So, having a high glucose level over time isn’t good news, because it almost ages your body.


Let’s start with a basic understanding of insulin. When glucose levels are too high - such as what happens after eating sugary foods, carbohydrates or a huge amount of protein - the pancreas releases a hormone known as insulin which binds to the liver and muscle cells, signalling for them to remove glucose (a liquid form of sugar) from the bloodstream and store it as insoluble glycogen (a solid). The problem is that, depending on our build, the liver and muscle stores combined only hold around 300–500g of glycogen, which in terms of calories is just 1,200 to 2,000, after which all excess glucose becomes stored as body fat (also known as adipose tissue).


On the other hand, when our blood sugar levels are too low, the pancreas releases a hormone know as glucagon that breaks down insoluble glycogen (solid) into soluble glucose (liquid), allowing it to be released into the bloodstream for use as energy or when it breaks down glycogen in a muscle that itself needs energy, it uses it as its own fuel.


Glucagon; what I call the slender hormone, works in the opposite direction to insulin. The two of them need to work in partnership to ensure the right amount of glucose is in the blood.


The role insulin performs in the human body is similar to the role of nacre inside an oyster. Pearls are formed in oysters, when a foreign body such as a grain of sand enters the shell and begins to irritate the fleshy little creature inside. In an act of self-defence, the oyster excretes a layer of nacre over the intruder. Trouble is - with its new, shiny, larger coating -this little intruder becomes even more irritating. So the oyster, which obviously isn’t overly bright, excretes another layer of nacre over the original layer. This event is repeated over and over again, until eventually the oyster is prised open and a gleaming pearl pops out.


The way a pearl is created is very similar to the role of insulin in the body. After we have eaten food with a sugary content, or after the body has converted CARBS into sugar, the body cries out for help in getting rid of the poisonous interloper. Yes, our body sees sugar as a poison. The pancreas steps up and secretes the hormone insulin all over the sugar, in an action not dissimilar to the oyster, secreting nacre over its unwanted intruder. But our body is brighter than the oyster and decides not to leave it in a place where it’s going to constantly irritate us, but instructs insulin to march off, carrying excess sugar to our fat stores.


The trouble is, when we keep sending lots and lots of insulin to our fat stores, they get overcrowded and often become what is known as insulin sensitive or insulin resistant. It’s a bit like being in a noisy office – we notice the distraction at first, but eventually we just block it out. For those who eat too frequently, and who consume lots of CARBS, the end result might be hyperglycaemia (chronically elevated sugar in the blood) or hyperinsulinemia (dangerously high amounts of insulin in the blood).


This is what often causes type 2 diabetes, when overconsumption of CARBS leads to the cells shutting up shop and not letting insulin do its job. Incidentally, type 1 diabetes is much rarer and is a very different condition. For those suffering with type 1, the body isn’t able to generate sufficient or any insulin to transport the CARBS and other sugars from the blood and into the body, and therefore most sufferers have to inject themselves with insulin.

insulin resistant

For those who have type 2 diabetes, while the medical profession once regarded it as a chronic, progressive and irreversible disease, thousands of people in Great Britain are now putting their type 2 diabetes into remission by living more primally. Please be aware that I am not claiming that living a primal way of life will reverse everyone’s type 2 diabetes, as it varies from person to person. However, if a sufferer strictly follows a high (quality) fat, medium protein and extremely low CARB eating regime - adhering to the primal foods that we recommend later - and intermittently fasts (which we also cover later), there is a strong likelihood that they can reverse their type 2 diabetes.

Before we start to look down on insulin, we should remember that the hormone is only doing the job nature designed it to do! When we are eating healthily, rather than seeing it as a prison officer escorting a villain to the fat cells, we should view insulin as an usher in a church, accompanying energy to each and every seat. Insulin is one of the most critical hormones in the metabolism of food, and our cells are unable to process glucose without it. As long as we don’t consume too many CARBS, just as it has for more than 2 million years, our insulin system functions perfectly. But when we regularly eat a diet too rich in CARBS – a diet that we were not designed to eat, just like a Harley Davidson is not designed to run on diesel – it causes serious damage to our engine. Let’s keep it as simple as possible with an equation:

CARBS lead to sugar in the blood and the creation of insulin.
Too much insulin = insulin resistance
Insulin resistance + overweight = Type 2 diabetes
Looking at the above equation, it’s logical to come to the conclusion that type 2 diabetes is in fact the intolerance of too many CARBS! 

Dr David Unwin

Dr David Unwin

Insulin is kind of a boss hormone. Insulin is designed to get rid of sugar because sugar in the blood is dangerous. So, in a sugary environment, insulin switches off your ability to burn fat. Our body is like a hybrid car. It can either burn sugar or fat, but not at the same time. Before I knew all this, I used to eat biscuits all day. I wouldn’t be able to burn fat. My own insulin had switched off my ability to burn fat. And in a way that would explain very interestingly why, while I was eating biscuits all day, I was continually hungry and yet I had got a big tummy. Because I had got fuel there, but I could not reach it. Because I was in a sugary environment, that same sugar stopped me from burning my own belly fat. And now I have gone low carb, I am quite slim, simply because I can now burn my own body fat.


Let me explain further about hormones. As I mentioned earlier, they are chemicals that send messages from one part of the body to another. The intended recipient of the hormone has what are known as receptors on its surface. Often, the analogy of a key and lock is used to explain their function. The hormone being the key, which floats around the body until it finds a receptor (the lock), which it can open. When cells are constantly offered sugar from the bloodstream, they may become insulin resistant.


Picture it as the locks freezing up and rejecting the keys. The result is that the sugar can’t enter the cell and therefore it stays in the bloodstream. Too much sugar in the bloodstream confuses our immune system - which had worked flawlessly for Homo Sapiens in our hunter/gatherer days - so the body instructs the pancreas to keep producing more and more insulin. But that obviously doesn’t solve the issue, because once the cell’s receptors aren’t working, no matter how many keys we throw at the locks, they just won’t open and let the glucose in. So now it’s a twofold problem. There are now high levels of both glucose and insulin roaming around creating havoc in the bloodstream. For the caveman, at the end of summer stuffing his face full of ripe, sugary apples, this was not an issue. While he would still experience a huge spike in insulin, without refrigerators to keep the fruit fresh, it would all have been consumed over a week or two and then his food would revert back to his normal low carbohydrate staples. But in Great Britain, where we can have whatever food we want 365 days a year, it’s not so much a short spike in insulin that causes the problem, but the on-going daily consumption of sugary foods over a prolonged period.


Dr Dan Maggs

Dr Dan Maggs

After consuming a meal, our blood sugar level will rise, and insulin gets to work. While all foods have an effect on insulin, carbs and other sugars cause insulin to work overtime. While insulin is active, the last thing our body will want to do is to burn off any energy from our fat stores. Put simply, when sugar is in our bloodstream, no matter how hard we exercise, we aren’t going to lose weight. Insulin and fat burning work almost exclusively on their own.

Energy Sources and Storage

Our body can run on three types of fuel. For immediate use, it burns glucose. When that’s not readily available it calls upon glycogen and eventually, when it is out of both glucose and glycogen, it consumes fat.

  • Bloodstream – Glucose (liquid sugar) is burnt for energy.
  • Liver – Can store approximately 100g (400 calories) of glycogen (kind of a solid sugar).
  • Muscles – Can store 300 to 500g of glycogen. That’s approximately 1,200 to 2,000 calories, enough fuel for an hour or so workout.
  • Body fat - Can store 10,000 to 25,000g of fat. That’s a whopping reserve of energy, some 40,000 to 100,000 calories. 

Recap Of Insulin, Glucagon and Glycogen

When we eat CARBS/sugar, the pancreas creates insulin to get rid of the excess sugar in the bloodstream and insulin converts glucose (the liquid form of sugar) to glycogen. If the two glycogen stores are full, excess CARBS/sugars are converted to body fat. On the flip side of the coin, if there is too little sugar in the bloodstream, the pancreas creates a different hormone called glucagon which does the opposite to insulin: it informs the liver to convert stored glycogen back to glucose and then stored fat back into usable energy.

They sound ridiculously similar, but it’s crucial to remember the difference between glycogen and glucagon:

Glycogen (pronounced gly-co-jen) – is a type of solid sugar (a starch/ polysaccharide) and is the first storage form of sugar in the body. It is stored in the liver and muscles.

Glucagon (glue-ka-gone) – is a hormone sent to the liver with an instruction to reconvert solid glycogen to liquid glucose. Glucagon performs the opposite task to insulin.

Dr Jason Fung

Dr Jason Fung

Glycogen is like a wallet, in that money goes in and out constantly. But like a wallet, while it is easily accessible, it can only hold a limited amount of money. Like the wallet, glycogen is able to quickly convert back to glucose to provide energy. Whereas fat is like a bank account, it’s harder to access but has unlimited storage space.


Healthy salad