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7 Reasons Diabetes Isn’t Caused By Carbs

Today I’m going to tackle one of the biggest myths in the Type II Diabetes world: that too many high GI carbohydrates (sugar) cause Type II Diabetes.

The idea is that the excess carbohydrates lead to an overproduction of insulin, which eventually leads to your pancreas getting worn out and not being able to produce enough insulin. Thereby causing type II diabetes.

(Note: I’ll just use the term diabetes from here on out to keep things simple.)

I’ll be showing you why this concept doesn’t make sense. And I’ll be proving that carbohydrates per se aren’t bad and that the focus on them is not helpful to getting relief from diabetes (or avoiding it).

Here are 7 key reasons why this theory doesn’t make sense:

1. High Carbohydrate Countries Like Japan And China Have Very Low Rates Of Diabetes

One of the biggest issues with the idea that carbohydrates cause diabetes are the fact that many countries around the world eat a moderate to high carbohydrate diet and yet almost never get diabetes. Let’s take a look at the Okinawa population of Japan for instance.

The Okinawans are a population living in the Northern Islands of Japan, they are widely regarded as being one of the healthiest and longest living populations on earth. Their rates of disease are exceedingly low and diabetes is no exception.

What do they eat to keep so well?

Well, their diet is 69% sweet potatoes (1). Now admittedly sweet potatoes have a lower GI than normal potatoes, but they are still carbohydrates and relatively high carbohydrates. And having a diet of almost 2/3rds sweet potatoes will definitely put a strain on the pancreas. But the fact of the matter is, this population doesn’t get diabetes at rates anywhere near that of the Western world. Rates of heart disease, cancer and other diseases show similar trends.

This is just one population, we have the rest of Asia that eats similarly and also has similarly low rates of disease.

Bottom Line:
One of the healthiest living cultures today lives on a very high carbohydrate diet and yet their rates of diabetes and pre-diabetes is very low.

As an interesting side note. Of the Japanese people who moved to the USA, it was the ones who adopted the Western eating habits that got diabetes more than their more traditional counterparts (40). You may say this is obvious, but that’s not the interesting part. The interesting part is that these people ate lower amounts of carbs in the Western diet than they did in Japan. So lower carbs lead to higher diabetes.

2. The Highest Carbohydrate Eating Society On Earth Don’t Get Diabetes

For further proof let’s take a look at one of the most extreme hunter gather societies on earth. The Tukisenta of Papua New Guinea. This population is extreme because their diet is almost 90% carbohydrate from high GI sweet potatoes. These people don’t have access to modern medicine and more than 50% of them smoked heavily, which is highly associated with diabetes risk (2).

So you would expect this population to be overweight, diabetic and dropping like flies.

Well, this couldn’t be further from the truth. You see, when researchers looked at this population they found not a single case of diabetes, or even high blood sugar (3). In fact, in 14% of the people tested, their blood sugar was actually lower after the 1-hour glucose test than their fasting rate.

Let’s take a look at their blood sugar tests:

tukisenta glucose tolerance

You’ll note that the top two lines are for a typical town in the USA called Tecumseh. These are included to give you an idea how the native population compares to the western world. As you can see the Tukisenta, with their high carbohydrates diet, scored well below that of normal westerners. And this study was done in the 60’s when diabetes for a town like Tecumseh was much less prevalent than it is today. So their results are even more impressive.

The researchers concluded: “no evidence of diabetes was found in this survey.”

Now you could make the argument that this population was genetically protected from diabetes. And indeed this could account for some of the good health of this populations, but the researchers looked into this as well. They added that while the incidence of diabetes in New Guinea was very low in rural areas, it is very high amongst people who have had long contact with western civilisations.

So these people were not genetically predisposed to being free from diabetes.

In fact, the researchers suggested that they are actually much more prone to diabetes than normal people.  Which explains why they get much higher levels when they are in contact with the western world.

They experienced absolutely no obesity at all, and their weight actually decreased with age, rather than the increase we in the western world have come to assume is normal.

One could make the argument that because this society exercised more than the typical westerner, they were protected from diabetes. But exercise, while very good for diabetes, isn’t a panacea. It will help, but it will not explain a complete absence of diabetes and even high blood sugar. And remember, this population smoked like chimneys, and were genetically prone to getting diabetes.

So there we have it, the highest carbohydrate diet in the world and they don’t get diabetes. This is pretty definitive proof that carbohydrates per se don’t cause diabetes.

Does this mean you can go out and buy a trolley full of white bread, sugar, coke and other delicious carbohydrates? Absolutely not. But we’ll get to how certain types of carbohydrate can lead to diabetes a bit later.

Bottom Line:
A diet 95% made up of starchy carbohydrates doesn’t lead to diabetes in this population, despite the fact they smoke like chimneys and are genetically susceptible to diabetes.

But first, let’s look at the claim that the pancreas gets exhausted from all that insulin action:


3. Other Organs Improve With Increased Use… So Why Not The Pancreas? 

What happens when you go to the gym and start to work out those muscles of yours?

Your heart muscle gets stronger. The body does this to increase your ability to pump blood to the rest of your body. Your veins and arteries also get wider and more flexible, so they can accommodate more blood flow. Your haemoglobin count increases so you can transport more oxygen from your lungs to your body. Your lung function increases.

Your whole body basically gets stronger and fitter.

Your body realises that the need for these muscles and organs is increased, and so it grows them and makes them more efficient.

But no one is arguing that you should stop using your muscles for fear of having a heart attack or “wearing out” your muscles are they? So why would the pancreas need to be used less?

It’s the same with the brain. Studies have shown that increasing the use of different areas of the brain increases their size and efficiency (4). So using your brain a lot leads to a better performing brain. But increased learning doesn’t lead to headaches, does it?

But what about the pancreas?

Well, the pancreas has more uses than just to pump out insulin. The pancreas is responsible for excreting digestive enzymes into your digestive system when you eat. Without the pancreas, most of your food would pass through you undigested and you would become incredibly malnourished and eventually die.

How do we know that this aspect of the pancreas is still working well, even after it has been overworked well beyond its original intention?

Well if you look at the weight of a typical westerner today, compared to 50 years ago, you’ll see that the pancreas has been worked far more than it was intended to. The simple way to look at is this; to maintain the weight of an overweight person, the pancreas would need to churn out way more digestive enzymes than it was ever supposed to. And it does this just fine. Looking at the extreme side of things, even someone 2-3 times their healthy weight has no trouble getting enough enzymes into their stomach. The pancreas is doing 2-3 times more work than it’s supposed to do… and it’s fine.

So the question raised is: why would the pancreas work perfectly at excreting enzymes well beyond its natural abilities, but stop producing insulin at all when used a bit more than it was supposed to? The answer is that overuse is not a good explanation of why the pancreas stops producing insulin.

Bottom Line:
The body is set up to become more efficient when certain organs and muscles are used more than normal. The brain, muscles, vascular system and even pancreas either work perfectly well or actually improve with use. To think that the insulin-secreting part of the pancreas is any different is quite a stretch.

Which brings me to my next point:


4. High Carbohydrate Diets Lead To Better Carbohydrate Metabolism, Not Worse

Yes, you read that correctly, in a number of studies when a high carbohydrates diet is given to people, their glucose tolerance actually gets better!. This happens in normal healthy people (5)(6)(7)(8) and has been shown to happen in diabetic and hyperglycemic populations (9)(10)(11)(12)(13)(14)(15)(16).

But there’s a problem, there have also been several studies that show that a high carbohydrate diet actually leads to worse glucose tolerance in diabetic and healthy people (17)(18)(19)(20).

So what’s going on here?

Well there’s a few reasons that we could potentially point to:

1. The degree of severity of diabetes could play a role in these studies. Ie those that have very severe diabetes could be skewing the results if they are not handling the high carbohydrate diet.

2. Most of the studies that showed improvement used higher carbohydrate than the ones that showed no improvement. Hinting that there might be some magic behind a very high carbohydrate diet (75%+) that isn’t seen in a normal high carbohydrate diet (60%). This could be because a lot of what leads to diabetes comes from foods that are found in moderately high carbohydrate foods. So we end up eating more of these diabetes causing substances with the carbs and accidentally blame the carbohydrates. See the end of the article to see what we know causes diabetes.

3. Most of the studies that showed an effect from a higher carbohydrate diet were also older studies. Suggesting that what the carbohydrates were in the newer diets was the reason for the lack of improvement, and not the carbohydrate itself. So, in this case, it’s the type of carbs that matter and not the carbs per se. Indeed this has been pointed out in one of the studies above (ref 13). This dovetails nicely with the above point.

Whatever the reason, what we can absolutely conclude is that:

A high carbohydrate diet CAN be okay for normal and diabetic people alike IF the carbohydrates are from the right source AND if the underlying cause of the diabetes is removed. What matters isn’t the carbohydrates per se, but the type of carbohydrates.

But the plot thickens still…

Because in some studies when people are put on a low carbohydrate diet, their glucose metabolism actually gets worse, not better. As measured by an oral glucose tolerance test (ref 8)(21)(22)(23).

I know this doesn’t really make sense at all on the face of it. After all, when you go on a low carbohydrate diet you find that your blood sugar levels drop considerably right? Well, the reason for this is simply because there are fewer carbohydrates to be disposed of in the body. If the body no longer has exposure to high amounts of carbohydrates, it will become less efficient at dealing with the carbohydrates it does become exposed to. So if a person does a blood glucose test after a low carbohydrate diet, according to the above studies, they will perform worse than before, not better.

Bottom Line:
Several studies have shown an increase in the body’s glucose metabolism abilities from high carbohydrate diets. This is true for both diabetics and healthy people. Some studies also show that blood sugar metabolism actually gets worse from low carbohydrate diets.

Now on to my next point:


5. High Carbohydrate Studies Show Impressive Improvements In Diabetics

There have been a number of impressive clinical trials where the carbohydrate intake either didn’t matter or actually helped improvements in diabetics.  I’ll discuss three here:

Study 1 (24)

29 patients with impaired glucose tolerance were put on either a paleo type diet or a Mediterranean diet for 12 weeks. Both groups were borderline obese when they started the study.

After 12 weeks both groups improved in a number of parameters. There was a 26% drop in AUC glucose in the paleo group relative to a 7% drop in the Mediterranean group. At the beginning of the study in the paleo group there were 12 people with elevated fasting glucose. Of which 10 had full-blown type II diabetes.

At the end of the study, every single person had normal blood sugar levels!

But here’s the clincher: the improvement in these people was independent of their carbohydrate intake. Meaning that the amount of carbohydrates they ate during the study had nothing to do with their improvement. There was, however, an interesting association. Total grain intake was associated with a lower improvement. So this hints at the type of carbohydrates being important and not carbohydrates per se. Indeed this has been shown in other studies (25).

Study 2 (ref 15)

100 patients were put on what’s known as the “rice diet”. Which is mainly made up of white rice, fruit juice and other high GI carbohydrates. The total carbohydrate content was in the range of 95%. So very extreme.

The patients were observed for different amounts of time, but the average was 22 months.

The results were rather astounding:

  • Average fasting blood sugar dropped from 202 to 155, and;
  • Insulin went from 25 units to just 17

So these full-blown diabetics improved their levels significantly on a diet that most would assume would kill the average diabetic!

Study 3 (26)

28 Asian-Americans and 22 Caucasian-Americans, all of whom were at risk of diabetes were put into two groups:

Group 1 ate a typical western diet for 16 weeks. The diet ended up being 50% carbohydrates, 16% protein and 34% fat.

Group 2 ate the same diet as above, but after 8 weeks they switched to a “traditional Asian diet” for another 8 weeks. The traditional Asian diet consisted of 70% carbohydrates, 15% protein and 15% fat.

So basically what we have here is a comparison of a standard western diet of moderate carbohydrate, versus a standard Asian diet of high carbohydrates. So what were the results?

By the end of the study, those that were following the traditional Asian Diet had lost weight and improved insulin sensitivity, while the group on the typical western diet gained weight and had a worsened metabolic profile.

So there we have it. Three trials that all showed how carbohydrates are either unrelated to improvement, or actually helped glucose metabolism.

Bottom Line:
Some clinical trials have shown that improvements in the condition of diabetes can be separate from the amount of carbohydrates consumed. Other trials have shown that higher carbohydrate intakes actually lead to improved outcomes relative to lower carbohydrates. We can conclude that carbohydrate intake isn’t the important measurement in improvement.


6. Most Studies Show No Increased Diabetes Risk With Higher Carbohydrate Intake

Yep, you heard it right, there have been a couple of observational studies that show that a higher carbohydrate diet is actually associated with lower diabetes risk than low carbohydrate. In the San Luis Diabetes Study (27), the researchers looked at 1,317 subjects in two counties in Colorado. They looked at their carbohydrate intake and also noted who got diabetes and who didn’t.

This is their conclusion: The findings support the hypothesis that high-fat, low carbohydrate diets are associated with the onset of diabetes.

Further evidence comes from a recent review article published in the Journal Of General and Family Medicine (28). They took a look at all of the observational studies looking at carbohydrate intake and diabetes risk. In all, they found 11 studies with a total study population of 440,669, of which 27,887 people had diabetes.

They found that after they had compiled all of the data, an interesting story emerged. This is their conclusion: “The risk of incident diabetes among individuals with a low-carbohydrate diet was not significantly different from that of individuals with a high-carbohydrate diet”. Meaning that carbohydrate intake had absolutely nothing to do with diabetes risk. High or low, it didn’t have any impact.

Now observational studies do have very significant downsides to them. But in general, if you can’t find a correlation between two things (in this case diabetes and carbohydrates) then the association doesn’t exist.

A further review study looked at randomised controlled trials with diabetics and low carbohydrate diets (29). Randomised trials are a lot better at getting to the truth of a matter than an observational trial. A randomised trial can actually pinpoint if one factor can actually cause a different factor. So in this case, if a low carbohydrate diet can actually improve diabetes risk.

So what were the results?

8 studies were found that met the author’s inclusion criteria. The data was compiled and believe it or not, they found that there was no difference between the low carbohydrate diets and higher carbohydrate diets. The acknowledge that low carbohydrate diets are safe and effective over the short term, but that the evidence suggests that longer term there is no difference.

Bottom Line:
In a review of all of the observational studies looking at carbohydrate intake and diabetes risk, no association was found between high intake and diabetes.
A review of all the low carbohydrate diet studies found no association between these diets and a higher carbohydrate diet. Even though short-term low carbohydrate diets worked well.

And now we get to the final nail in the coffin of this concept:


7. The Theory Behind Why Beta Cells Dysfunction Is Flawed

So we’ve seen that too much use of the pancreas (from increased carbohydrate intake) doesn’t cause diabetes in real life. But for good measure about we take a look at the theory of why beta cells “wear out”.

One of the theories is called Glucose Toxicity.

Glucose Toxicity is the concept whereby hyperglycemia (too much glucose in the blood) leads to a reduction in insulin secretion and an increase in insulin resistance (30). The glucose interacts with the beta cells in a number of ways and worsens their function. This is a well-known concept.

This theory is intuitively correct, as we know that diabetes is defined by increased blood sugar levels. Which would lead to lower beta cell function. But can glucose toxicity lead to diabetes. Is glucose toxicity one of the causes.

Well, let’s look at a study that looked at beta cell function in a range of people from normal non-diabetic, overweight, and diabetic (31).

The researchers looked at the pancreas in 124 deceased people. What they found was rather interesting:

In obese patients with no diabetes, beta cell volume was increased compared to lean non-diabetics. This alone should be a red flag for the “tired pancreas” theory, as obese people would need much more insulin for their dietary requirements. And so the body comes to bat and increases the number of beta cells to do this job.

Type II diabetes patients had up to a 63% lower beta cell volume than non-diabetics.

But here’s the most interesting part: the group with only impaired glucose tolerance and not type II diabetes had a 40% lower beta cell volume compared with healthy controls. This implies that beta cell volume decreases before the onset of diabetes and even before impairment of glucose tolerance.

Remember, the proposed mechanism is: too many carbohydrates -> too high blood sugar -> impaired beta cells. But if beta cell destruction happens at normal blood sugar rates (which the above study shows is the case), then blood sugar levels would never get high enough to actually cause destruction to the beta cells.

So we can conclude that high glucose levels increase diabetes progression from further impairment of beta cells, but we can’t conclude that this is the original cause of type II diabetes.

Bottom Line:
Beta cell dysfunction happens while blood sugar levels are still normal. Meaning that what is causing the dysfunction is not the blood sugar. Uncontrolled high blood sugar causes further beta cells to dysfunction, but normal blood sugar levels don’t have any effect.


So Can I Go Out And Gorge On Carbohydrates?

Not so fast, because diabetes is characterised by an inability to handle carbohydrates, it’s still a good idea to restrict them to control your diabetes. If you just go out and eat as many carbohydrates as you want, you’re only going to shoot up your levels higher and cause more damage. But… and it’s a bit but, if you remove the other causes of diabetes first, then you can slowly increase your carbohydrate intake to see how you do.

But… it’s really important what type of carbohydrates you’re eating.

Because high carbohydrate foods are very often really bad for you anyway… but not because of the carbohydrate content. More because of everything else that normally comes along with them. Let’s take a look at some high carbohydrate modern foods like pizza, pasta, soft drinks, doughnuts, chips etc.

Here’s what’s included with these high carbohydrate foods:

  • Most of them are really high in bad fats as well (contributing to obesity from overeating, inflammation (32) and free radicals (33).
  • High in sucrose – table sugar (which creates dangerous toxins in your bloodstream that destroy tissues (34), increases inflammation (35), contributes to weight gain (36), increases bad cholesterol (37) among other things.)
  • Highly processed with added preservatives, artificial flavours and colours.
  • High in grains (which can lead to increased gut permeability and inflammation (38))
  • Lack fibre
  • Low in vitamins and minerals

Pretty much all of the above have been implicated in diabetes and other chronic diseases.

But let’s look at what’s known as “safe starches” like a baked sweet potato, steamed rice, pumpkin and other root vegetables. Here are some of the similarities:

  • High in fibre
  • High in vitamins and minerals
  • Low in fructose
  • Not processed
  • No added artificial preservatives, colours or flavours
  • High in bioflavonoids and antioxidants

It’s obvious from the two lists above that we have been unfairly been focusing on the carbohydrate aspect of foods. Eat a high carbohydrate diet from the first list and you will get diabetes. Eat a high carbohydrate diet from the bottom list and you’ll be perfectly healthy.

So now that we’ve cleared all of that up, let’s take a closer look at diabetes:


So What’s Really Going On In Diabetes?

We know that diabetes is caused by two things happening in the body:

  1. Beta cells in the pancreas dying and dysfunctioning (39)
  2. insulin resistance of cells (ref 39)

Beta cells in diabetic people are impaired and also die much quicker than they are supposed to. However, unlike Type I Diabetes, the production of more beta cells is not impaired at all (ref 31). So all that needs to be done is to stop the beta cells from dying and stop things interfering with their function. Once this is done the beta cells can slowly regenerate and you can start producing enough insulin again. But this is not helpful unless you fix insulin resistance as well:

Insulin resistance is when the cells in the body are resistant to the effects of insulin. Insulin, as you know, is needed to push energy (glucose) into cells. So when the cells don’t respond to insulin’s actions, the glucose has nowhere to go but to stay in the blood stream. So to fix diabetes we need to fix insulin resistance and beta cell dysfunction.

Luckily, both insulin resistance and beta cell dysfunction are not permanent problems, and so removing what caused them in the first place will in most cases reverse type II diabetes. Big claim I know. But the paleo diet from above proves that it’s possible.

Bottom Line:
Diabetes is caused by the beta cells in the pancreas dysfunctioning, and the cells in the body resisting insulin. A high carbohydrate diet without removing the underlying causes of diabetes is not a good idea. Removing the causes will result in the body being able to metabolise carbohydrates again, so carbohydrate increases can be tested.


So What Are The Root Causes Of Type II Diabetes?

These are what we know contributes to diabetes:


Environmental Toxins: man-made chemicals, insecticides, pharmaceuticals, heavy metals  

Advanced Glycation End Products


Poor Micronutrient Status 



Remove or normalise these and we have no more diabetes!

Stay tuned! As I’ll be tackling each of these at a later date, along with what can be done to fix diabetes once and for all!

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