Category Archives: Insulin Resistance

What happens to the carbs – part II

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My interest in nutrition began many years ago as part of my over-riding interest in cardiovascular disease. This means that, unlike many other people, I backed into this area with no great interest in the effect of food on health. For most doctors nutrition takes up about an hour of the medical degree course. We are pretty much given to understand that it is of little medical significance. Eat a balanced diet…end of. I also paid nutrition about that much heed.

However, because of the power and influence of the diet/heart hypothesis I felt the need to understand more about this whole area, and how the system of digestion and metabolism actually worked. At first my interest was purely to find out if there was any clear and consistent association between diet and cardiovascular disease (which I shall call heart disease from now on, as it is simplest to do so).

Like many others, before and since, I could not find any such association. Nor could I find any biochemical or physiological reason why saturated fat, in particular, could cause heart disease. That issue, of course, represents a long and winding road that I am not going down here.

However it did not take long before I became side tracked by the very powerful and consistent association between heart disease and diabetes. People with diabetes have far higher rates of heart disease than people who do not. In the case of women with diabetes, the increase in risk hovers around five times the rate of non-diabetics. So it became clear that I would need to understand diabetes, if I was going to fully understand heart disease.

This led me into the looking at the underlying causes of diabetes (type II). At first it seemed blatantly obvious that type II diabetes was primarily due to insulin resistance (it is far less clear now). In its simplest form, insulin resistance means that you need a higher level of insulin to drive down blood sugar levels, because something is ‘resisting’ its effects. Of course, like everything else, it is rather more complex than this, but I will leave it at that for now.

It also became clear that you can have mild/moderate insulin resistance for many years before you develop frank diabetes. Confronted with resistance to its effects, the body simply increases insulin production to keep blood sugar within the normal range. In this state, sometimes called ‘pre-diabetes’ you do not actually have a high blood sugar, especially not in the fasting state. This, of course was when most blood sugar level measurements were taken. Yes guys, look for a metabolic condition when it isn’t actually visible …very sensible.

However, mild to moderate insulin resistance, even if blood sugar levels are not consistently raised, is not benign. It is associated with a whole series of other metabolic abnormalities such as: central obesity, raised VLDL/triglycerides, low HDL, high blood pressure, high levels of blood clotting factors – to name but a few. In addition you can also find higher sugar levels, and higher insulin levels in the post-prandial state (after eating). Most importantly, to my mind, mild to moderate insulin resistance is also associated with a far higher rate of heart disease.

In the early days, ‘pre-diabetes’ came under many different monikers. Just to give you four:

  • Reaven’s syndrome
  • Syndrome X
  • Insulin resistance syndrome
  • Metabolic syndrome

This caused a lot of initial confusion, but once I chased them all down, it because clear that these different names were simply describing the same phenomenon, which is probably best described as insulin resistance syndrome. Although this title carries its own problems.

The next question, of course, is what causes the insulin resistance? The wisdom was, and remains, that it is caused primarily by obesity. This was based on the observation that, as people got fatter, the risk of diabetes increased almost exponentially. One paper I read many years ago stated that younger obese women had around forty times the risk of diabetes, compared to women of normal weight. That is what you call a strong association. Perhaps causation may even be whispered?

In short, if you added together what was clear about diabetes and insulin resistance, you got a model of type II diabetes which looked pretty much like this:

  • You eat too much food
  • You put on weight
  • As you put on weight you become more and more insulin resistant
  • At first you will develop insulin resistance syndrome
  • If you keep putting on weight you will become so insulin resistant that you will develop frank type II diabetes

I call this the ‘blowing up a balloon’ theory of diabetes. As a balloon expands you have to blow harder and harder to overcome the resistance. As you get fatter and fatter you need more and more insulin to force fats into fat cells. As with many things in medicine this is a nice simple story. It is also very easy to understand, and it is tantalisingly close to being correct

As always, however, when presented with a model like this, my immediate reaction is to try and smash it to bits with contradictory evidence. I figure that any theory that can withstand repeated assault is likely to be correct. On the other hand.

I started by looking at the extremes, as I always do. Beginning with the most obese group people on the planet earth, namely Sumo wrestlers. I wanted to know how many of them have diabetes, and it did not take long to discover that, whilst in training, none of them have diabetes.

I then searched for the opposite end of the spectrum. Were there people with no adipose tissue, and how many of them had diabetes? Surprisingly, there is one such group, the least obese people on earth. They are those with Beradinelli-Siep lipodystrophy. This is a genetic abnormality which means that these poor unfortunates have almost no fat cells. How many of them have type II diabetes? Well, all of them actually.

I then looked for the population with the highest rate of diabetes in the world. This happens to be the Pima Indians of North Mexico/Southern US. I have seen figures reporting that over 80% of adult males Pima Indians have type II diabetes. It may even be more. And yes, they are very obese.

However, there are two other very interesting facts about the Pima Indians. First, they have a very low rate of heart disease. Or they did last time I looked. Perhaps most importantly, in their youth, when they are not obese, they produce far more insulin in response to food than ‘normal’ populations. Or, to put this another way, they are hyper-insulinaemic before they are obese, and long before they become diabetic. So their excess insulin production is not a result of becoming fatter. The causal chain is the other way around.

I have found that if you speak to most doctors about these facts, a look of complete incomprehension passes over their faces. ‘That cannot be right.’ Of course if you believe in the ‘blowing up a balloon’ model of diabetes, then the Pima Indians, Sumo Wrestlers and those with Beradinalli-Siep lipodystrophy do not make any sense. However, in science, when observations do not fit your hypothesis, it is the hypothesis that needs to change, not the facts.

Just to summarize these ‘paradoxical’ facts:

  • You do not need any fat cells to develop diabetes/if you have no fat cells there is a 100% probability that you will be diabetic
  • You can be very , very, obese and not have diabetes
  • You can have increased insulin production long before you become obese (and/or insulin resistant). You become obese later

Just to remind you of the current model.

  • You eat too much
  • You get fat
  • As you get fat you become more insulin resistant
  • In order to overcome this resistance you produce more insulin
  • Eventually you cannot produce enough insulin, the system ‘burns out’ and you develop type II diabetes

Where and how can the paradoxical facts be fitted? The answer is that they cannot. Ergo, the model is wrong. However, luckily, there is another model that fits all the facts. One that I prepared earlier:

  • You produce too much insulin
  • This forces your body to store fat
  • You become obese
  • At a certain point insulin resistance develops to block further weight gain
  • This resistance becomes more and more severe until…
  • You become diabetic

This model explains the Pima Indians. Can Sumo wrestlers be fitted into this model? Yes, with a couple of addendums. Sumo Wrestlers eat to become fat, because added mass provides a competitive advantage if you are trying to shove someone else out of a small ring, before they do it to you.

To achieve super-obesity, they wake up, train for two hours, then eat as much as they can of a high carbohydrate, low fat, broth. They then lie about for a few hours allowing the high insulin levels created by the high carbohydrate diet to convert excess sugars to fat, storing this in adipose tissue. Later on they train very hard again, then eat, then sleep. Rpt.

The reason why they do not become diabetic is on this regime is simply because they exercise very, very, hard. They burn up all the sugar/glycogen stores in the liver and muscle whilst exercising, which means that when they eat, the sugar(s) can – at least at first – be easily stored in muscle and liver (so there is no insulin resistance to overcome). However, once these guys stop training, things do not look so good. Diabetes lurks..

Those with Beradinelli-Siep lipodystrophy have the reverse problem to Sumo Wrestlers. Because they have no fat cells there is nowhere to store excess energy to go. If they eat carbohydrate/sugar, the first 1,500 calories can be stored as glycogen – after that there is nowhere left. If the liver converts sugar to fat, there is nowhere for that to go either. So, you get ‘back-pressure’ through the system. It doesn’t matter how high the insulin level gets, if you have nowhere to store energy you have nowhere to store energy. End of.

Whilst those with lipodystrophy cannot tell us much about diabetes and obesity in ‘normal’ people. This condition does make it very clear that diabetes – insulin resistance, high insulin and high sugar levels – is primarily an issue with energy storage and how the body goes about this storage, and the role that insulin plays. If there is somewhere for excess energy to go easily, insulin levels will not go up, and nor will blood sugar levels.

But what of ‘normal’ people. Can normal people be fitted into the updated model of type II diabetes? Well, of course, they can. But you need another step in the new model, the first step. Which means we have a new causal chain, and it looks something like this ‘You eat too much carbohydrate.’ Adding in this step gives us the new model:

  • You eat too much carbohydrate/sugar
  • You produce too much insulin
  • This forces your body to store fat
  • You become obese
  • At a certain point insulin resistance develops to block further weight gain
  • This resistance becomes more and more severe until…
  • You become diabetic

The best thing about this model is that it works. It is not contradicted by Sumo Wrestlers, Pima Indians of those with lipodystrophy. It explains the association between obesity and diabetes, and how insulin resistance develops. It may not be perfect, but it is a bloody site better than the simplistic model we have got. The one that says, if you eat fat, you will get fatter, then diabetic…. Bong! If you are diabetic you should eat carbohydrate and sugar, not fat…Bong!

How long before mainstream medicine rejects this mainstream model? Another fitty years or so, I would guess

Thinking about obesity and diabetes

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Outside of heart disease and statins, another area I have been studying for many years is diabetes. Not type I diabetes (caused by destruction of beta-cells in the pancreas and a lack of insulin), but type II diabetes. Type II diabetes has nothing to do with a lack of insulin, it is generally considered to be caused by insulin resistance i.e. enough insulin is produced, but there is ‘resistance’ to its effects.

This resistance firstly drives up the insulin levels. However, as it worsens, the raised insulin levels are no longer sufficient, so the blood sugar levels rise anyway. At first the fasting sugar levels may be normal, but the response to a sugar ‘test’ shows an abnormally high level about an hour later. This is why a glucose tolerance test (GTT) used to be the way of diagnosing early stage type II diabetes.

This has been superseded by the HbA1c test. This test, essentially, looks at the amount of glucose that has stuck to your red blood cells over the last month. Which gives an idea of what the ‘average’ sugar level has been over a longer time period. It is a better measure.

Anyway, without getting too bogged down in technical details, the model that is used to explain type II diabetes is very simple.

  • You eat too much
  • You become obese
  • As you become more and more obese you become more and more insulin resistant
  • Your insulin level rises to overcome this resistance
  • At some point the resistance become too much
  • You develop raised blood sugar levels aka type II diabetes

I call this the ‘blowing up a balloon’ model of diabetes. As the balloon expands, you need to blow harder to get more air in.

This model (or variations thereof) is almost universally agreed, by almost everyone. It should come as no surprise, therefore, that I do not agree with it. Yes, there is not the slightest doubt that diabetes and obesity are related. In fact, there is no doubt that obesity; insulin resistance and type II diabetes are closely related.

Equally, there is no doubt that if people lose weight, their diabetes can go into reverse, and ‘reversibility’ is one of the most powerful pieces of evidence possible in proving causality. So where exactly, you may think, is my problem?

My problems first started with the recognition that you can find far too many direct contradictions to this model. Just to look at two examples. First we can look at the least obese people in the world. Those unfortunates who have a condition called ‘Beradinelli-Siep generalised lipodystrophy’. In this condition you have no fat cells – at all. So, of course, the rate of type II diabetes in these people would be zero…right? Wrong, the rate of type II diabetes is 100%.

Then we have Sumo wrestlers, the single most obese group of people on earth. So, they all have severe insulin resistance and type II diabetes right…? Wrong, whilst in training, none of them have type II diabetes.

In short:

  • Thinnest group of people in the word, 100% diabetes
  • Fattest group of people in the world 0% diabetes

Or to put this another way round, it is clear that obesity is neither necessary, nor sufficient to cause type II diabetes. If you were a follower of Bradford Hill, or Koch, of Popper this, effectively, writes off obesity as a possible causal factor for type II diabetes.

But, but.

But what?

To move sideways for a moment or two. When you first read about type I diabetes, one of the things that stands out is that those diagnosed with type I (at least in the past) lost weight very rapidly. They grew thinner and thinner, becoming almost like skeletons – before they all died. Why?

Why, is because insulin is the energy storage hormone. It does not just affect blood sugar levels. In fact, the almost obsessive focus on the interplay between insulin and blood sugar has blinded almost everyone to the fact that insulin does far more than just lower sugar levels. It affects fat, protein and sugar metabolism. It interacts with many different pathways in adipose tissue, muscle cells and the liver. Lowering blood sugar may be, in some ways, the least important thing that it does.

The reason why you die in type I diabetes has little to do with blood sugar levels. You die because, without insulin, fats escape from adipose tissue and travels to the liver as free fatty acids. In the liver these fatty acids are automatically converted into ketone bodies (which the body uses for energy in a fasting state).

The ketone bodies are, in turn, acidic, and in a high concentration they cause ‘acidosis’. This acidity overwhelms the alkali buffering systems, and you die in a keto-acidotic coma. To reiterate, it is not the high sugar that kills you in type I diabetes, it is the uncontrolled release of fats. This has nothing to do with sugar at all – except indirectly. Which, although you may not think it, returns us to the matter in hand. Namely, what is the association between obesity and diabetes?

As we have seen, without insulin, fats escape from fat cells at a high rate, so you lose weight. If we turn this though one hundred and eighty degrees, it should be clear that, if you have too much insulin in your bloodstream, fat can no longer escape from fat cells, and you will get fatter and fatter.

Essentially, insulin is obesogenic. A fancy way of saying that if you produce too much insulin you will become obese. An amazing fact ‘discovered’ in August 2014

 

“DALLAS – August 25, 2014 – UT Southwestern Medical Center researchers have identified a crucial link between high levels of insulin and pathways that lead to obesity, a finding that may have important implications when treating diabetes.”[1]

Yes chaps, well done. You made a breakthrough discovery of the absolute bleeding obvious. You mean, insulin makes you fat? Well who’d a thunk? Well, lots and lots of people actually. At which point, let me introduce you to the Pima Indians of North America. This race has an almost unbelievably high rate of type II diabetes. It is greater than 50%. Perhaps more. Are they obese, yes? Of course. However, of greater interest is that Pima Indians, long before they become obese and/or diabetic, produce far, far, more insulin than any other race [2]:

‘The normal and prediabetic Indians had fasting and stimulated insulin levels during all the tests two-to-threefold greater than the Caucasians. Differences in insulin levels between the two races could not be explained by differences in glucose level, age, or obesity.’

Interesting… It is clear that the model with the Pima Indians is, as follows:

  • You produce too much insulin
  • You become obese
  • You become insulin resistant
  • You develop type II diabetes

Of course, it is not just the Pima Indians where this happens. This causal chain works for us all. It contains most of the same ‘factors’ as the blowing up a balloon model of diabetes (although you will notice it does not contain the ‘you eat too much’ factor). However, as you can also see, the facts are in a different order. I like to call this, the correct order.

In short, yes, obesity, insulin resistance and diabetes are closely associated. But not quite in the way that everyone believes.

Moving on. What, you might think, would cause people to produce too much insulin. Well, what foodstuffs cause the greatest rise in insulin levels? Why, let me think… Yes, carbohydrates would cause the greatest rise in insulin levels. So if you eat lots of carbohydrates, you will produce lots of insulin. Insulin forces fats into fat cells and stops it escaping. Insulin is obesogenic… Join those dots ladies and gentlemen.

P.S. Pop quiz. What do you think happens if you try to force blood sugar levels down in type II diabetes by prescribing insulin?

P.P.S. So why does everyone with Beradinelli-Siep syndrome have type II diabetes? Answers on a postcard please.

1: http://www.utsouthwestern.edu/newsroom/news-releases/year-2014/august/high-insulin.html

2: http://www.ncbi.nlm.nih.gov/pubmed/89223