The Facts on Insulin, Insulin Sensitivity and How To Avoid Diabetes

I grew up hearing the word “insulin” a lot.  Especially when we’d visit my grandparents on my mom’s side of the family in Indiana.   I didn’t know what it was at the time but I figured it must be important because my grandma was always getting on him about eating candy and taking his insulin like it was a matter of life or death. 

The topic didn’t go away either, as both of my parents became diabetic and needed to inject insulin multiple times per day it was always a household topic of conversation.  

Insulin is still a hot topic and you can’t talk about nutrition without it coming up. People get really religious about some parts of nutrition and nutrition science.  They dig their heels in and refuse to look at thing from any perspective other than the one they already have.  Insulin is one of those polarizing topics.  Some take a hard line approach, preaching that insulin (and carbohydrates) is to blame for the global obesity crisis.  Others think insulin is the key to building muscle and should be elevated at all times.  As always, the truth is probably somewhere in the middle. 

Let’s try to take an objective view of insulin today and come out with balanced understanding of the topic. 

We’ll cover:

What is insulin?

What is insulin’s job in our body?

Why is insulin so important?

What is insulin sensitivity/resistance?

What causes insulin resistance?

How can we improve our insulin sensitivity?

Does it make us fat?

What are the different types of diabetes?

How do I maintain a healthy relationship with insulin and avoid problems?

What is Insulin?

Insulin is a “messenger” hormone produced by special clusters of cells in the pancreas.  Remember the pancreas from back in biology class?  It’s a gland in your endocrine system that secretes hormones and enzymes responsible for all kinds of important stuff from blood sugar regulation to digestion.  It’s a pretty big deal. 

Now we know WHAT insulin is, so what? 

What is Insulin’s job in our body? 

We established that Insulin is a messenger hormone secreted by the pancreas.  Well what’s the message and who’s getting it?  

I’m so glad you asked.  

When we eat food our body needs to break it down into things that it knows how to use.  Carbs get converted to glucose, protein gets converted to amino acids and dietary fat gets turned into fatty acids.  That gets them into the bloodstream.  Now that they’re in our blood and ready to use they need to be told where to go.  Enter insulin, the messenger.  

When we eat, our pancreas releases insulin to get out there and tell that food where to go.  It tells our cells to take in the different nutrients that we ate into our muscles and tissues.  It tells those cells to either use or store those nutrients.  As those nutrients are absorbed, the amount of insulin in our blood goes back down to the level it was at before we ate. 

Pretty cool right? 

So why is insulin so important? 

Since the role of insulin is to get nutrients like glucose, amino acids, and fatty acids transferred from our blood into our cells it helps us regulate our “blood sugar” level.  That means the amount of glucose that’s in our blood at any given time.  Without insulin, and the right amount of insulin secretion, our blood sugar levels would go unregulated and climb quickly after eating a meal creating a hyperglycemic condition that could result in death.  If you know someone who’s diabetic you already know how important blood sugar levels are.  More on that later.    

Not only does insulin signal cells to absorb glucose (sugar) but it also tells our fat cells to absorb fatty acids in the blood as well as triggering the shuttling of amino acids into cells. 

Throughout the day we’re in constant ebbs and flows of insulin secretion and cell absorption based on our food intake and activity.  Remember, our body craves homeostasis and uses processes like this (through hormones like insulin) to achieve it.  

Does insulin make us fat?

We’re always looking for smoking gun when it comes to fat and weight gain.  Something to blame it on that we can simply “cut out” and never have to worry about calories, hunger or any of that fancy science stuff.  Insulin certainly gets a lot of flack when it comes to this.  Remember, when we eat we secrete insulin in order to get those nutrients shuttled into our cells.  Well one of those nutrients is fat. People demonize insulin thinking that if you minimize insulin you’ll minimize fat storage and therefore lose weight.  I guess this is a case of “shoot the messenger”.  Get it? Since insulin is a messenger hormone?  Nevermind.

This line of thinking is flawed though.  It’s too simplistic.  Does insulin cause fat to be stored in our fat cells?  Absolutely.  As a matter of fact, throughout the day we’re going  back and forth between stages of fat storage and fat oxidation (burning) depending on when and how much we’ve eaten.  After we’ve eaten we’re in storage mode. Once the nutrients in our food have been absorbed our bodies switch back over to burning mode.  The average of those two states (storage vs. burning) is what determines if we store extra energy as fat or if we use stored fat for energy.  In other words, put in more energy (calories) than you need on average and you’ll gain fat.  Put in less energy (calories) than you need over time and you’ll lose fat.  

So while insulin is directing this process, having insulin in your blood shuttling nutrients does not cause you to gain weight.  A surplus of calories does.  

What is insulin sensitivity/resistance?

Don’t be so sensitive!  Well in this case, we do want to be sensitive. 

Insulin sensitivity refers to how well your cells respond to the signaling of the insulin being released by your pancreas.  Remember all of those important things that insulin does that we just went over?  Well if your body isn’t good at “hearing” those instructions from insulin, we have a problem on our hands. 

When we’re not “sensitive” to insulin we’re “resistant” to it and you’ll commonly hear the term “insulin resistance”.  They mean the same thing.

People with poor insulin sensitivity still produce insulin in their pancreas, but they don’t make enough to overcome their decreased response to it.  

Insulin resistance is not good, but it's really common. Nearly 90 Million Americans are believed to have it to varying degrees.  The signs of having it are often first noticed because of the results of your blood sugar not being controlled by insulin.   Those high blood sugar symptoms can include things like increased hunger (insulin suppresses hunger), fatigue and mental fog/confusion.  

Picture this whole insulin sensitivity thing like a dimmer switch instead of a normal “on/off” switch.  As the switch moves closer to being less sensitive to insulin we move closer to having diabetes (more on that later).  As the switch moves the other direction and we become more sensitive to insulin, we move closer to health and further from diabetes.  

There must be something pretty common going on that causes insulin resistance if so many people have it right? 

In short, yes.  The most common cause of insulin resistance and the conditions leading to diabetes is excess body fat (obesity) and lack of activity.  A waistline of over 40 inches in males, 35 inches in females, are also common in people with insulin resistance.  Other potential causes are conditions like Polycystic Ovary Syndrome (PCOS), Cushings Disease, Smoking and a family history of diabetes. 

So why the link to body fat and obesity?

Researchers believe that increased levels of fat, especially visceral fat in and around our liver and other organs plays a vital role in insulin resistance.  These fat cells are inflammatory in nature and having an excess of them impairs the signal reception of insulin.  That in turn makes the pancreas attempt to create more insulin to pick up the slack.  Unfortunately there is a limit to how much insulin we can secrete and the demand ends up outpacing the supply.   

But fear not!

Much of your ability to keep the dimmer of your insulin sensitivity slid away from disease is in your control, even if you’ve already started down a bad path. 

How to improve your insulin sensitivity

Your best attack on improving your insulin sensitivity is a 2 pronged approach to lifestyle modification.  You may not be able to pick your parents or predisposition to some conditions but you’re not helpless to make great changes. We’ll touch on these here and go into more detail at the end of this article.  

Prong 1: Exercise - Exercise (both cardio and weight lifting) has been proven beyond a doubt to increase insulin sensitivity.  Both immediately and long term.  Research shows that a single bout of exercise lasting 25-60 minutes can boost insulin sensitivity for up to 3-5 days.  Keep that up several times per week and you are on your way.  Since we’re all about practicality, make sure you choose a way of exercising that you actually enjoy.  You’re much more likely to stick with it long term, and that’s where the magic happens.  

Prong 2: Body Fat Reduction - I’m not talking about liposuction here!  I’m talking about changing your nutritional habits.  A reduction in body fat requires a prolonged period of a caloric deficit.  You need start paying attention to your total caloric intake and make sure that on average you’re consuming less calories than you’re burning.  That deficit in calories will cause your body to oxidize fat from your fat cells which in time will both decrease your body fat level and increase your sensitivity to insulin.   Many “diets” can cause weight loss, but if they do it’s because they helped achieve a caloric deficit.  More on this later.

So why bother worrying about this?  What happens if we don’t address poor insulin sensitivity? 

Diabetes

Diabetes is a group of diseases that results in having too much glucose (sugar) in the blood.   There are 4 main types of diabetes.

Type I Diabetes - About 10% of diabetics have Type I diabetes.  You can either be born with it or develop it later in life.  In Type I diabetes your pancreas doesn’t make insulin at all (or minuscule amounts).  This type is also called “insulin dependent” diabetes. Since your body doesn’t make any insulin you have to control your blood sugar by injecting insulin directly into your tissue so it can tell your cells to absorb glucose and bring blood sugar levels down.  There isn’t any cure for Type I diabetes as of now and people who have it have to become very aware of their blood sugar levels and rhythms in order to maintain healthy levels.   Even though there isn’t a cure doesn’t mean that Type I diabetics can’t use those same lifestyle adjustments (exercise and body fat reduction) to give themselves the best long term health outcomes.   Type I diabetics can drastically reduce their risk of conditions like heart and blood vessel disease, nerve, circulation and kidney damage by keeping their blood sugar in normal ranges and staying active and lean. 

Pre-diabetes - You’re not born with pre-diabetes, you develop it over time.   Pre-diabetics don’t produce enough insulin and/or have developed resistance to insulin which is causing elevated blood sugar levels.  If your fasted blood sugar levels are between 100 and 125 you’re considered to be pre-diabetic.  Genetics are believed to play a partial role in whether you become pre-diabetic or not.  If either or both of your parents are Type II diabetic your risks are increased.    Conditions like PCOS can also predispose you to having pre-diabetes.  The good news however is that most people develop pre-diabetes as a result of an overall unhealthy lifestyle.  Wait, did I just say that’s good news?  YES!  Because those factors are in our control and by taking control of them, pre-diabetic people can actually reverse the condition and maintain healthy blood sugar levels.  Even sleep is important in reversing pre-diabetes. Research shows that even 1 or 2 nights of really bad sleep can put blood sugar levels in the pre-diabetic range.  Left unchecked, pre-diabetes is just a pitstop on the way to Type II diabetes. 

Type II Diabetes - Re-read everything you just read about pre-diabetes because it all applies to Type II diabetes.  If you’re pre-diabetic and don’t make changes to your health and lifestyle you’ll develop Type II diabetes.  Type II is diagnosed as having a fasted blood sugar level above 125 (pre-diabetes was 100-125). It’s not uncommon for Type II diabetes to need to inject insulin as well as take other medications to help control their blood sugar.  People with Type II can minimize the effects of their poor insulin production and insulin resistance the same way as pre-diabetics can.  You want to hear some really good news?  Type II diabetes (and insulin resistance) can be completely reversed through diet, exercise and body composition change.  That’s a really big deal.  

Gestational Diabetes - Like it sounds like, this is diabetes that begins while a woman is pregnant.  We don’t know exactly why gestational diabetes happens although obesity, a sedentary lifestyle and PCOS increase the risk of occurrence.  We do know that blood sugar in gestational diabetes can be controlled and managed with the same 2 pronged approach as Type II diabetes and Pre-diabetes.  Typically blood sugar levels return to normal after delivery although mothers that go through gestational diabetes may be at an increased risk for developing Type II diabetes later in life.  So for them  it’s even more important to keep healthy habits and a healthy body fat level.  

How to have a healthy relationship with Insulin and avoid pre-diabetes and Type II diabetes

You don’t want diabetes.  More people die from diabetes every year than breast cancer and AIDS combined.  Diabetes can lead to many life threatening conditions and can dramatically reduce quality of life.  Do you want to draw blood from your finger 5 times a day and inject yourself with a needle before each meal?

Like we’ve talked about, there are things outside of your control like genetics that might throw you off track in regards to how your body produces and uses insulin.  Let’s not focus on the things outside of our control.  

The thing within your control that can have the biggest impact on maintaining good insulin sensitivity and avoiding diabetes is getting to and maintaining healthy body fat levels.  Body Mass Index (BMI) is a useful tool for most people when it comes to measuring this.  Here is the CDC’s BMI calculator tool for adults.    A BMI between 18.5 and 25 falls within the “normal” range.   BMI isn’t the “be all end all of health markers” but it’s a good estimate for most people. 

So what do we do if we’re over weight, obese or our BMI is too high?  We need to decrease our body fat through an energy restriction.   Good ol’ calories.  We need to eat less calories than we’re burning on average for a long enough period that our body taps into our reserve energy (fat).  The more fat you have, the longer it will take.  As body fat is burned for energy our fat cells shrink and our health markers will take a turn for the better.   We wrote an in depth article about metabolism, calories and fat loss that will walk you through the process of finding out how many calories you need.  We also wrote our own calculator that you can download that will help you set your calories and macronutrients for fat loss.  We also offer 1 on 1 nutrition coaching to help people through this process. 

A balanced diet of mostly lean proteins, lots of vegetables, some fruit, nuts, seeds, and very little processed foods and sugars are an excellent place to start.  Eating these types of foods most of the time will leave you feeling energized, less bloated, and well recovered too.  

Fat loss takes time, so pack your patience and don’t give up if you aren’t shredded in two weeks.  Your health is worth the effort.

Another important part of maintaining insulin sensitivity and avoiding diabetes is physical activity and exercise.  Exercise lowers blood sugar by stimulating our cells to absorb and use glucose even in the absence of insulin.  Not only that but exercise improves insulin sensitivity in both the short and long term. I swear that I’m not trying to be dramatic, but besides being overweight, inactivity (not exercising) is the thing that puts you at the most risk for developing diabetes.  If you’re inactive you’re likely to over consume calories.  If you routinely over consume calories you’ll become overweight and more insulin resistant which can easily lead you to becoming pre-diabetic and then diabetic.  Research studies show that Type II diabetics who institute and stick with an exercise plan show increases in insulin sensitivity and decreases in BMI.  

So how much should you be exercising?  The American Diabetes Association recommends a minimum of 2.5 hours of moderate to vigorous exercise per week.  In addition to that they recommend 2-3 weight lifting sessions per week and no more than 2 consecutive rest days.  That’s no joke right?!  Let’s throw a caveat in that if you’re currently doing nothing, don’t go straight into trying to do everything.  You’ll burn out, get too sore and give up.  Start small.  Do something, then do a little more next week.  Then do a little more the week after that.  Nothing will work if you can’t sustain it.  Choose a plan that you enjoy and one with some accountability to keep you going. 

I hope the main takeaway from this article is that Insulin is important but not evil.  Don’t focus on a special fad diet to “conquer the evils” of insulin.  Take a step back and look at your overall health.  Take the smart approach to lifestyle changes that will set you up for the best long term success.  Thanks for reading and please reach out if you have any questions or to apply for coaching.