There is a common belief that a ketogenic diet can make you insulin resistant, which is where the cells in your body become less receptive to the hormone insulin.

This hormone is in charge of helping to transport glucose into cells for energy and of regulating blood sugar levels, amongst other things.

Blood sugar levels are elevated if there is insulin resistance.

As we know, the purpose of a ketogenic diet is to reduce carbohydrate foods to the point where your body starts using stored fat for energy instead of glucose.

This perceived problem of insulin resistance is observed when you are on a strict ketogenic diet for a longer period of time.

What we start seeing are issues such as:

• Insulin levels elevated for longer

• Insulin not working as effectively

• Blood sugar levels taking longer to come down

• May require more insulin to regulate blood sugar

I have personally seen these effects occur when on a ketogenic diet.

For context, I am a type 1 diabetic who has experimented with a ketogenic diet for the last few years. I monitor my blood sugar levels very closely using a continuous glucose monitor (CGM).

When I first started noticing these effects I was so confused and concerned.

I had seen such great results up until this point and my blood sugars were in the best control they had ever been.

Why am I becoming more resistant to insulin? I thought keto improves insulin resistance?

Being as insulin sensitive as possible is what you need to be striving for, particularly as a diabetic, type 1 or 2.

This is for many reasons, but mainly for improved blood sugar control and lowering insulin requirement.

After lots of research and understanding what I have found is that these effects I was seeing were not due to becoming more insulin resistant in the negative sense we think about when we refer to this, but due to other normal and natural processes happening in the body.

What I want to do in this post is dispel this notion that a ketogenic diet causes you to become more insulin resistant.

Read on.

By the way, nothing I am saying is advice. I am not a doctor. Just sharing my knowledge and experience for educational purposes.

So firstly, let's go dive more into what insulin resistance actually is.

We are going to discuss two types of insulin resistance today:

1. Pathological

2. Physiological

Pathological Insulin Resistance

This is essentially the insulin resistance that is bad.

As we said before, insulin resistance is where the cells in our bodies become less receptive to the hormone insulin.

But what causes this to happen?

There are two ways that (I believe) this happens:

1. There is too much insulin in the body

2. Eating a diet high in fat

To address the first point, if insulin levels are constantly elevated your cells will become more and more resistant to it.

This results in the pancreas, or more specifically the beta cells of the pancreas to secrete more insulin to keep blood sugars in range.

Eventually, as the resistance worsens and the beta cells are overworked, they begin to not work properly or at all.

This is pathological insulin resistance, which is the precursor to disorders such as pre-diabetes and type 2 diabetes. This usually happens slowly over a longer period of time.

To address the second point, high amounts of fat can coat the insulin receptors of cells, making them less insulin sensitive.

This again leads to more insulin being produced and more workload on the pancreas.

I have learnt this from the people at Type 2 Diabetes Revolution (https://type2diabetesrevolution.com).

They explain that it is saturated fat that is the problem which I don't personally agree with, but I do agree that too much fat contributes to less insulin sensitive cells.

However, what I have learnt and seen from my experience is that the resistance is temporary.

Fat doesn't cause long term pathological insulin resistance.

What causes insulin levels to be elevated?

The thing that causes the biggest insulin response are carbohydrate foods.

Now I don't want to demonise carbohydrates in this article, nor is my belief that all carbohydrates are bad.

Fruit and complex carbohydrates like lentils and sweet potato are great, especially if added into a low fat meal.

I do believe however that we can all agree on one thing, and that is that refined carbohydrates and high amounts of sugar are a problem for diabetics, if not for most others too.

What I'm referring to here mostly are foods such as your cakes, biscuits, chocolate and greasy fast food.

The problem is that refined carbohydrates raise insulin higher than complex carbohydrates - a lot higher.

Also, these foods typically also contain high(er) amounts of fat which doesn't help with insulin sensitivity as I have explained.

The pancreas is working overtime to regulate blood sugar when you are eating refined carbohydrates, and then even harder as there is typically a lot of fat in the food as well.

It is my belief that this combination is the main problem in the modern day when it comes to insulin resistance related issues.

In regards to a keto diet, this issue of fat is where the belief comes from around keto diets causing insulin resistance.

While yes it is high in fat so insulin sensitivity might be impaired, it is different because insulin levels are still low on this diet, so the pancreas isn't being overworked.

Lower insulin levels = less insulin resistance

The main takeaway here is:

The biggest contributor to long term, pathological insulin resistance is insulin levels being high.

High fat essentially adds fuel to the fire, but isn't the main issue.

Physiological Insulin Resistance

Physiological insulin resistance is good and a normal process in the body.

From research I understand that the brain requires some glucose to function.

As glucose levels on keto diets are low, the body’s natural and normal response is to spare any glucose available for the brain to keep us alive, instead of transporting it to other cells in the body.

Also, the normal insulin response is delayed as the body isn’t used to the carbs.

These mechanisms are seen when you have been on keto for a while and have become fat adapted i.e. have transitioned to using fats for energy as the primary fuel source.

The clue is in the name - it's a "physiological" change.

Your cells aren’t used to running on carbohydrates and glucose at this point.

This may mean insulin levels and blood sugar levels are elevated for longer.

You might start wondering that you are becoming insulin resistant, I certainly did, especially if you see your blood sugars in real time using a CGM like I do.

I usually get a bigger blood sugar spike than others when I do have any carbohydrates, particularly refined carbs or sugar.

It’s not really an issue if I have a small amount of complex carbs like sweet potato, lentils etc.

But it’s not that you are becoming insulin resistant in the bad sense or unable to metabolise carbs on a keto diet, it’s just that it may take a bit longer to as our body isn’t used to them.

To round this off, this sort of resistance is not the same as pathological insulin resistance.

It is temporary and occurs as a normal response of the body when you have become fat-adapted.

The normal insulin response will return if you start introducing carbs again into your diet, even though this may take a while depending on how long you have been fat-adapted.

Dropping a resource here if you want to learn more about this: https://optimisingnutrition.com/physiological-insulin-resistance/

Useful Tips for Dealing with Physiological Insulin Resistance

Here are some useful tips to deal with physiological insulin resistance and if you introduce carbs back into your diet:

• Eat slow digesting/complex carbs

  It is important to introduce carbs slowly when you have become fat adapted, whether you are a diabetic or not.

  Some good options are sweet potato, lentils, brown rice.

  Avoid refined carbs such as white bread, white rice, but mostly the sweet treats. Be careful of high glycemic fruits too such as bananas and grapes.

• Reduce fat

  This will help in metabolising the carbs easier if you introduce them.

  If you are noticing that blood sugars are taking really long to come down or fasting blood sugars are still high, then you might consider reducing fat to help with this.

• Fasting

  When you do have carbs try to incorporate some fasting the next day, whether that means skipping breakfast or a longer fast.

  I notice my blood sugars take longer and more insulin to come down when I do have carbs.

  Fasting will help with this as it improves insulin sensitivity.

• Gym/walking

  This is a massive one.

  I would really consider pairing any carbohydrate consumption with a walk afterwards and/or a gym session, whether that is lifting weights or anything else.

  It has almost an immediate positive effect on my blood sugars.

Key Takeaways

There are two types of insulin resistance: "Pathological" and "Physiological"

Pathological insulin resistance is a long term issue and is the root cause of type 2 diabetes.

Physiological insulin resistance is a normal and temporary response of the body when on a ketogenic diet. This phenomenon is not the same as long term insulin resistance that we refer to in a negative sense.

Being on a keto diet and becoming fat-adapted does cause issues in metabolising carbs as your body isn’t used to them.

When consuming carbs after being on keto long term we should introduce them slowly, going with more complex carbs and avoiding high amounts of refined carbs and sugar - which is what we should all be doing anyway, diabetic or not!

Again, just want to reiterate that I'm not a doctor or researcher in this field.

This information is from my own experience and understanding having been on a ketogenic diet on and off for the last few years as a type 1 diabetic.

Purely sharing to help others.

That's all for now, thanks for reading!

Umar