By Dr Joe
Health enthusiasts are always keen to explore the question of how to increase insulin sensitivity and for good reason too.
Insulin has been implicated in the causation of a lot of chronic diseases. It therefore makes sense to keep insulin levels low.
We need insulin to survive by the way. Without insulin, our body will simply pack it all in.
The problem is that we need just little insulin to survive. Any more than we need to drive forward our metabolic needs, the insulin becomes a problem in itself. The trick is getting that balance right.
Insulin is a polypeptide hormone which means it is made up of several amino acids joined together to form a huge molecule. Like I said previously, insulin drives a lot of our metabolic processes and that process starts with driving glucose from the blood circulation into the cells in particular, muscle cells.
> Seeing as muscle cells are responsible for 85% of the glucose uptake from the blood circulation, what happens inside our muscle cells is important to us. Insulin has a role with glucose metablosm in the liver as well.
What is insulin sensitivity?
Before diving into how to increase insulin sensitivity, let’s get back to the basics and know what insulin sensitivity actually is, first of all.
Eating leads to a breakdown of macronutrients to smaller units. Fat gets broken down to fatty acids. Protein gets broken down to amino acids and carbohydrates are broken down to glucose to greater extent and fructose to a smaller extent.
The smaller units in particular glucose needs to mopped off the circulation into the cells where it is needed by the mitochondria for energy production. The mitochondria is the part of the cell where energy is manufactured. Mitochondria is the energy factory, if you like.
To get the glucose from the blood into the cells, you need insulin as the driver. Without insulin, that glucose is not going anywhere soon. The glucose will just float around the blood making itself a real metabolic nuisance.
That’s why Type 1 diabetics can become very unwell if they keep skipping on their insulin injections, because Type 1 diabetics can’t make their own insulin. It’s got to be administered by way of injection.
Type 2 diabetic’s problem is a different proposition altogether and it’s kind of related to what I’m talking about here about insulin sensitivity.
Insulin sensitivity refers to how much insulin is needed to drive a unit gram of glucose into the cells from the blood circulation.
If I need a small amount of insulin release from my pancreas (let’s say 8 units of insulin) to clear 1 gram of glucose from my circulation as an example, then I am insulin sensitive.
If on the other hand, I need let’s say 16 or 24 units of insulin from my pancreas to clear 1 gram of glucose from my circulation, then I am insulin insensitive or put in another way, insulin resistant.
Insulin resistant individuals need more insulin to clear the same amount of glucose from their blood circulation than insulin sensitive individuals.
> Being insulin sensitive is a very good thing. We should all be striving to become very insulin sensitive mainly because too much insulin in circulation leads ultimately to metabolic syndrome or what some scientists now prefer to refer to as insulin resistance syndrome.
Also, because insulin is a fat preservation hormone, high insulin levels in circulation makes losing fat difficult. To make matters worse lots of body fat compounds insulin resistance problem ultimately leading to Type 2 diabetes.
It becomes a vicious circle!
So how can I increase my insulin sensitivity?
This is always a common question: how do you increase or improve your insulin sensitivity? I like to look at the answer from a broader point of view. That way it becomes easy and less of a challenge trying to understand how to improve or increase insulin sensitivity.
What do I mean by this? Here’s what I mean: Look at increasing your sensitivity on the following broad headings.
- Anything you do to shed or reduce body fat, in particular visceral fat
- Anything you do to reduce your blood glucose level
- Anything you do to your improve your muscle performance and efficiency
That’s how you can increase insulin sensitivity in the broader sense. Before I get into specifics, I should point out that age is not a limiting factor when it comes to making you more insulin sensitive. You can boost your insulin sensitivity whether you are young or belong to the older age group.
Increase insulin sensitivity – How?
Here’s how. These 4 strategies below will boost your insulin sensitivity and optimize your health at the same time:
- Start a Regular Resistance Training Program
There’s a guy who is a personal trainer. He loves taking on people who have difficulty improving their insulin sensitivity. The first question this guy will ask you when you consult him is: have you lifted weights progressively yet?
If your answer is, No, then he’s not interested in taking you on.
For this personal trainer, he believes insulin sensitivity improvement begins with resistance training of any sort. Anything else is secondary as far as he’s concerned.
He might be a little extreme in his view but there’s a huge element of truth in there.
> For a start, muscle soaks up 85% of the glucose in our circulation. The more muscle fibres you have and the bigger the fibres are, the more glucose the muscle cells soak up from the blood circulation.
It is thought that a 10% increase in muscle mass translates to an 11% increase in insulin sensitivity. Makes sense?
You don’t have to be a beef cake to make yourself more insulin sensitive though. Just toning up is good enough, so long as you do it on a regular basis.
Twelve teenagers were studied to see the effect of weight training on their insulin sensitivity. These teenagers were obese with an average body mass index of 35 and body fat percentage of 40%. They were made to exercise all muscle groups for 12 weeks for just two times a week for 1 hour.
There was no dietary intervention at all in this study. The objective was not weight loss but increase in lean body mass.
Indeed, the teen agers had an increase in lean body mass. Their visceral fat constitution was unchanged but liver insulin sensitivity increased by 24% and there was a slowing down of glucose production from the liver, even though they did not lose weight over the 12-week period.
Another study looked at what effect weight training intensity and volume would have on insulin sensitivity. There was a positive correlation between resistance training intensity and volume.
High intensity, multiple set weight training produced the greatest result in reducing fasting blood glucose whilst increasing insulin sensitivity in the subjects of this study who were insulin resistant individuals.
The authors of the study even went as far as suggesting high volume, high intensity resistance training as an effective treatment for acutely reversing insulin resistance.
2. Do Aerobic Exercises to improve your insulin sensitivity
Just as weight training is proven to increase sensitivity, the same principle applies to cardiovascular training i.e aerobics.
Aerobic exercises encourage the clearance of glucose from the circulation just as sedentary lifestyle promotes rise in blood glucose.
Insulin sensitivity appears to be greater in muscles that are regularly trained. The more trained the muscle is, the more sensitive that muscle will be to gulping up glucose from the circulation.
That’s why it is essential to keep up with your whatever aerobics you engage in on a regular basis as regular exercise equates to improvement in muscle insulin sensitivity.
This study looked at insulin sensitivity in both younger and older women over a 6-month period of 3-times-a-week aerobic training. Each time insulin sensitivity was measured 3 – 5 days after the last exercise regime.
There was a reduction in visceral fat (internal fat) in both groups but more reduction in subcutaneous fat in the older age group than the younger ones.
Insulin sensitivity was seen to be boosted more in the younger age group than the older age group. There was improvement in insulin sensitivity in the older age group too but the essential difference is sustainability. As far as that research is concerned, insulin sensitivity is sustained more in younger women than older ones.
What does that mean?
It simply means the older you are, the more frequent your aerobic exercise routine needs to be for you to have persistent insulin sensitivity from aerobic training. If we go by that research finding where the exercise regime lasted only 25-60 minutes by the way
Another piece of research subjected 29 post-pubertal adolescents to 4-times-a-week 30-minute aerobic exercise regime for 12 weeks. Peripheral insulin sensitivity and liver insulin sensitivity were the outcome measures.
The subjects were recruited from 2 groups – one group was made up of lean adolescents and the other obese adolescents.
There was increase in peripheral insulin sensitivity as well as liver insulin sensitivity in both the lean adolescent group as well as the obese group. It’s just that the boost in insulin sensitivity was higher in the lean group compared to the obese group.
Something to remember is that these young individuals in the study were only doing the aerobic exercises for just 30 minutes and in fact, there was no weight loss. You can imagine what the results would be like if the exercise intensity was increased and there was actually weight loss.
How about the converse. Can you decrease insulin sensitivity by reducing physical activity?
Well, you can. This has been experimented in this study where 10 young men were made to reduce their physical activity for the purpose of this experiment. They were made to reduce their daily steps taken per day from over 10,000 to under 1,400 steps a day over a 2-week period.
This reduction in physical activity resulted in reduction of peripheral insulin sensitivity as well as a reduction in lean body mass worse in the leg muscles. There was a 7% reduction in cardiovascular fitness over the 2-week period.
> So being lazy decreases insulin sensitivity and raising your level of physical activity results in increase in insulin sensitivity.
Which brings me nicely to the next how to increase insulin sensitivity strategy.
3. Indulge in High Intensity Interval Training
We have seen how just 25 – 30 minutes’ normal intensity aerobic training exercise regimes in research experiments can boost insulin sensitivity.
What would happen if we turbo-charge the intensity of either resistance training or aerobic routines? Obviously, the benefit of reducing insulin resistance would get turbo-charged as well, won’t it?
If you think about it, you don’t need any research to prove that. Why? Because going back to the basics would provide a logical explanation for you.
When a muscle contracts, it needs energy to perform that function. The energy is provided by glucose. The muscle must use up the glycogen (the storage form of glucose) first. Once that glycogen is used up, the cell is hungry for more glucose if it is going to contract again.
That hunger for more glucose has to be satisfied by the circulating glucose, hence a contracting muscle soaks up more glucose because it needs it as a matter of necessity. Otherwise the muscle will fatigue out.
In the same vein, a muscle that contracts rapidly and frequently as happens in High Intensity Interval Training will use up its glycogen very quickly and will be hungry for even more glucose.
> You want to cash in on this physiological response to your muscles’ metabolic needs.
Need proof?
17 women with Type 2 diabetes were subjected to 2 days a week exercise for 16 weeks. They were randomised to either high intensity interval training (HIIT) or continuous moderate intensity exercise routine that lasted 40 minutes, cycling to be precise.
Both groups had reduction of total body fat and an increase in lean body mass at the end of the study. However, the reduction in abdominal fat and visceral fat was hugely significant in the high intensity interval training group.
This was accompanied by a reduction in HbA1C which is marker for improvement of glucose control over a 3-month period. HbA1C is a glucose monitoring tool used to manage type 2 diabetes in the long term
This finding is supported by this study which found glucose lowering capability on HIIT secondary to increase in fat cell and liver cell insulin sensitivity, although it should be mentioned that mice were the subject of this new study. What could be better than having your muscle cells, your fat cells and your liver cells become more insulin sensitive, courtesy of one strategy. You can’t beat that, can you?
If more proof is needed, then you can take a look at this meta-analysis that examined 50 well-designed studies involving high intensity interval training regimes and continuous moderate intensity regimes. Analysed them to see if there was consistency and significant proof that high intensity interval training (HIIT) does increase insulin sensitivity.
In the meta-analysis, there was consistent reduction of HbA1C and reduction in body weight. There was a reduction blood glucose in both groups but the difference in blood glucose lowering between the High Intensity Interval Training (HIIT) and continuous exercise was not statistically significant.
However, individuals who were at risk of developing type 2 diabetes, in other words those who are insulin resistant, experienced better reductions in fasting glucose in the high intensity interval training group compared to the continuous exercise group.
4. Avoid Refined Carbohydrates
One of the first things you must do to improve your insulin sensitivity or reduce insulin resistance is doing away with refined carbohydrates.
If you do nothing else, you must grab this strategy and run with it because it is so simple and it is very achievable.
Avoiding refined carbohydrates is all about habits. Changing life-long habits may be initially difficult but I can tell you once you start seeing refined carbs as metabolic health enemies, you would hardly go back to them.
Refined carbs tend to lead to quick elevation of blood glucose after eating. A rapid rise in blood glucose is a signal for high blood insulin release.
A rapid rise in blood glucose is fine, if you are very insulin sensitive, because the glucose will be quickly cleared from circulation by a small amount of insulin usually the first-phase insulin release.
But if you aren’t insulin sensitive or put in another way, if you are insulin resistant, then a refined carb meal will lead to more and more insulin being called up from the pancreas leading to hyperinsulinaemia (high insulin in circulation).
> Hyperinsulinaemia is the basis for a lot of the metabolic problems seen in metabolic syndrome (insulin resistance syndrome) which is best avoided.
To compound issues, a lot of processed refined carbs come loaded with refined sugar, trans fats and salt all of which are bad for insulin sensitivity. They actually promote insulin resistance. Not good!
One more thing I should mention here is the effect of some whole grains. Don’t always live in the hope that whole grains foods won’t spike your blood sugar. Some of them do.
> For instance, you will be surprised at how whole wheat bread will fire up your blood glucose levels even though the popular conception is that it is okay for you. Whole wheat bread doesn’t behave too radically different from white bread in terms of glycaemic index. The difference is only marginal.
Don’t make assumptions. If in doubt, test as advised on this page…even if you are not a diabetic.
Instead eat complex carbohydrates that are slow to digest because of their fiber content and will provide your gut with resistant starch. Resistant starch is a good probiotic for your gut bacteria which in turn is good for optimum health.
Insulin resistance and insulin sensitivity is one of my favourite topics and I could go and on about it with all the measures you can employ to increase your insulin sensitivity.
This piece about “what can I do to increase my insulin sensitivity” is long enough because I could continue to talk about other measures like the use of Resveratrol, L-Carnitine, Green Tea all of which would help you boost insulin sensitivity.
…but if you want more measures to sensitize your yourself to insulin, go here and go here too.
I should add that it is very easy to feel overwhelmed by all the strategies to increase insulin sensitivity or steps to reduce insulin resistance. However, you don’t have to do everything at once. Take 2 or 3 strategies and apply them to your everyday living and run with them. You can add some more as time goes.
That’s when you get the synergistic effect.
Suggested further reading:
1 Obscure Havard University Trick To Make ANY Exercise Program More Effective
Dr. Joe