Insulin – all you need to know

By Marwan / March 10, 2018

Whenever you hear the word insulin you automatically think of carbs! And whenever you think of carbs you think insulin!

How many of us have been to the gym where you hear the bro’s saying that they need to spike their insulin?!

What is insulin?

Depending on who you speak to, insulin is bad and that is the reason you get fat. As you will find out later on in the article insulin can either be your best friend or it can become your worst enemy.

Insulin is a hormone secreted by the pancreas. When you eat a meal, the carbohydrate in the meal is broken down into glucose (a sugar used as energy by your cells).

Your pancreas senses the rising glucose and releases insulin.  Insulin allows the glucose to enter your liver, muscle, and fat cells.

Once your blood glucose starts to come back down, insulin levels come back down too.  This cycle happens throughout the day.

You eat a meal, glucose goes up, insulin goes up, glucose goes down, and insulin goes down.  Insulin levels are typically lowest in the early morning since it’s usually been at least 8 hours after your last meal

Insulin doesn’t just regulate blood sugar.  It has other effects as well.  For example, it stimulates your muscles to build new protein (a process called protein synthesis).  It also inhibits lipolysis (the breakdown of fat) and stimulates lipogenesis (the creation of fat).

How does insulin work?

After you eat food and your blood sugar level rises, cells in your pancreas (known as beta cells) are signaled to release insulin into your bloodstream. Insulin then attaches to and signals cells to absorb sugar from the bloodstream.  Sugar cannot go into your cells directly.

As you eat a meal the body makes an instantaneous decision on how much sugar is needed now vs how much sugar is stored for future need.

This is dictated by insulin.  The more sugar you put in your body the more insulin will be released.

So in essence insulin keeps your blood sugar level from getting too high (hyperglycemia) or too low (hypoglycemia).

Insulin in overweight people

As the person becomes overweight, insulin problems increase.  The insulin receptors become unresponsive, the body is pumping large amounts of insulin from the carbohydrates but the body is incapable of using it properly.

Insulin resistance can happen because the insulin receptors on the cells are blocked from doing their job.  What happens when glucose doesn’t get to the cells?

Insulin isn’t capable of carrying out its job effectively it is no longer effective at transferring energy into the cells for use.

Insulin is being prevented from stimulating the transfer of glucose for energy, instead it’s all storage and that’s why overweight people feel tired most of the time.

Do carbs make you fat?

Below is how most people associate carbs and body fat.

High Carbohydrate Diet -> High Insulin -> Increased Lipogenesis/Decreased Lipolysis -> Increased Body Fat -> Obesity

Carbs alone won’t make you fat.   Fat gain can only occur if the rate of lipogenesis (formation of fat) exceeds the rate of lipolysis (fat breakdown).  In healthy individuals lipogenesis only happens after you consume a meal.

Carbs alone won’t make you fat, just as fat alone won’t make you fat UNLESS your total calories eaten exceed your total calories burned.

Refined Carbs and Insulin

You may be wondering why refined carbohydrates can be a problem.  Many people think it’s due to the rapid spikes in insulin.

However, it’s not insulin, because protein can cause rapid spikes in insulin as well.  One problem with refined carbohydrates is a problem of energy density.

With refined carbohydrate, it is easier to pack a lot of calories into a small package.  Not only that, but foods with high energy density are often not as satiating as foods with low energy density.

Insulin sensitivity

Insulin sensitivity refers to how well or how poorly the individual responds to the hormone insulin.  Individuals who are insulin resistant tend to have higher baseline insulin levels, because the body is releasing more to counter the resistance.

What causes insulin resistance?

There are a variety of factors that affect insulin resistance.  Genetics is one, your lifestyle such as diet, training, body fat levels.

But that doesn’t mean that lean athletes and/or bodybuilders cannot have some form of genetic insulin resistance.  At the same body fat levels between two different individuals insulin sensitivity can vary 10 fold.

How do I know if I am insulin sensitive or insulin resistant?

There are a lot of complicated and impractical ways to determine insulin sensitivity and insulin secretion. All involve blood work and looking at either baseline insulin or blood glucose or how insulin changes in response to a meal.

However, in practice, there are signs as to whether you have good insulin sensitivity or not and possibly whether you over-secrete insulin.

Here’s two very simple questions to ask yourself regarding your response to diet:

  1. On high-carbohydrate intakes, do you find yourself getting pumped and full or sloppy and bloated? If the former, you have good insulin sensitivity; if the latter, you don’t.
  2. When you eat a large carbohydrate meal, do you find that you have steady and stable energy levels or do you get an energy crash/sleep and get hungry about an hour later? If the former, you probably have normal/low levels of insulin secretion; if the latter, you probably tend to over-secrete insulin which is causing blood glucose to crash which is making you sleepy and hungry.

What would be the perfect meal for me?

This is dependant on you.  Different individuals tend to do better with different meals.  Some do well with low carb, high fats diet, others do better with high carb low fat diet.

Assuming, again, 40% protein, a good starting place might be 40% protein, 20-30% carbs and 20-30% fat. A further shift to a near ketogenic (or cyclical ketogenic) diet may be necessary, 40% protein, 10-20% carbs and the remainder fat may be the most effective. If protein is set higher, up to 50% protein, carbs would be set at 10-20% with the remainder (20-30%) coming from dietary fat.

If you are not insulin sensitive or tend to secrete high amounts of insulin in response to a meal Superior bodybuilders tend to have excellent insulin sensitivity with low insulin secretion in response to a meal.

This would tend to explain why bodybuilders have often gravitated towards high carb/low-fat diets and been successful on them.

At the same time, mediocre bodybuilders frequently get less than stellar results from that same diet. Lowering carbs and increasing dietary fat seems to be more effective in that case some of the low-carb bulking strategies out there probably work better for those individuals.

How to increase insulin sensitivity?

  • Do strength training – Insulin sensitivity is at its highest after exercise, the muscles and cells are desperate for fuel particularly after exercise.

Studies show all kinds of exercise help but anaerobic has the greatest impact on insulin sensitivity because it builds lean tissue.

  • Optimise your carb intake – Use carbs according to your activity and when your body needs it most, in and around your workouts.
  • Eat foods that improve insulin sensitivity with higher carb foods – green tea, vinegar, nuts, cinnamon and spices are among the foods that increase insulin sensitivity, improving the body’s ability to store carbs as glycogen rather than body fat.
  • Use whole foods rather than refined carbs.  Refined carbs cause a rapid rise in blood sugar.
  • Avoid liquid fructose – Liquid fructose causes insulin resistance and is linked with fat gain when consumed in large quantities.

Although fructose is metabolised in the liver and doesn’t stimulate insulin secretion in the way glucose does, fructose can interfere with insulin signalling and cause metabolic problems when taken in excess.

Final word on insulin – It is a “satiety” hormone which helps keep you full.

About the author


Hi, my name is Marwan and I set up this site to help skinny guys and girls just like you to end their frustrations and have the body of their dreams. I believe there are no limitations to what mankind can achieve.