Insulin and Bodybuilding

How to Harness This Natural Anabolic Hormone

By: Jeremy Fox, CNC, CPTPublished: June 2, 2020

Insulin is a critical hormone for overall health and fitness. But it conjures up thoughts of blood sugar problems and diabetes.

So how does insulin work? And how can you avoid health issues? In this article, I’m going to give you simple answers.

Plus you’ll learn what and when to eat to harness the power of insulin and transform your body.


What Is Insulin?

Insulin is a hormone produced in the pancreas. Its main job is getting blood sugar (glucose) to your cells to be used for energy.

Why Is It So Important?

Without insulin, glucose stays in your bloodstream. And that means you can’t get the energy you need from food.

More importantly, prolonged high blood sugar increases the risk of heart disease, stroke, and vision problems. That’s why people who don’t produce enough insulin have to inject it daily (type 1 diabetes).

Conversely, if people produce too much insulin it stops working properly (type 2 diabetes). And that results in additional risks like hearing loss, skin conditions, and sleep apnea.

While type 1 diabetes is mostly genetic, type 2 diabetes is caused by diet and lifestyle choices. Which is why it’s so important to understand how insulin works.

Even if you’re not at risk for diabetes, proper insulin function is vital for a healthy and energized body.

How Does Insulin Work?

To understand how insulin works, it helps to think of your body as a car. When you eat food it’s like putting gas in your tank.

From the tank, gas travels through fuel lines. Then a fuel injector valve delivers it to the engine.

Likewise, food in your stomach breaks down into glucose and enters your bloodstream. Insulin is like a valve that let’s glucose pass from your bloodstream into your cells.

role of insulin in body fuel system

Once in your cells, glucose gets burned for energy or stored for later use.

However, sometimes insulin doesn’t work as it should and your cells don’t get the fuel they need. This is called insulin resistance.

Insulin Resistance

Just as car parts break down without proper maintenance, your insulin response can wear out. Basically, your body tells the valve to open, but it gets stuck and only lets a little glucose through.

So when you press on the accelerator, you just sputter along instead of racing ahead. In other words, you feel fatigued and lethargic.

To fix insulin resistance, you need to flush the system and reset your sensitivity. That way you restore your responsiveness and use energy more efficiently.

3 Ways To Improve Insulin Function

It’s important to realize that insulin resistance is caused by constant high blood sugar and lack of exercise. Therefore, you need reduced blood sugar and increased exercise to reset sensitivity.

1. Reduce Refined Sugars

Another key point is that carbohydrates raise blood sugar significantly more than protein or fat. And the higher the glycemic index, the bigger the spike in blood sugar.

insulin and blood sugar levels by macronutrient

Therefore, it’s best to reduce carb intake to lower blood sugar. Especially high glycemic carbs from sweets and sugary drinks.

As a rule of thumb, aim to get less than 10% of your calories from sugar.

To find this number, drop a zero from the end of your calorie target. For example, if your goal is 2,000 calories per day, that’s 200 calories from sugar.

Then divide by 4 to get your target in grams. So 200 ÷ 4 = 50 grams of sugar per day (or less).

2. Eat a High Protein, Low Carb Diet

A high protein, low carb diet can significantly reduce 24-hour blood sugar levels according to a study by the University of Minnesota1.

For the first half of the study, men with type 2 diabetes consumed a diet of 15% protein and 50% carbs. Then they switched to a diet of 30% protein and 20% carbs.

After 5 weeks of the high protein, low carb diet their average 24-hour blood sugar levels dropped by 38%. Moving them from the diabetic range to a healthy level.

blood sugar-insulin before and after nutrition intervention

Adapted from Gannon, Mary C., and Frank Q. Nuttall

Not only did blood sugar remain lower after meals, but it was also lower first thing in the morning. That low fasted blood sugar is another sign of healthy insulin function.

As a result, this diet effectively reversed insulin resistance. And researches concluded it even has the potential to reverse mild to severe type 2 diabetes.

(This is one reason why Nutritioneering meal plans target 30% protein)

3. Include Regular Endurance & Resistance Training

Exercise also has a big impact on insulin function. Both endurance and resistance training significantly increase insulin sensitivity according to a randomized trial by the University of Vermont2.

insulin sensitivity and exercise

Adapted from Poehlman, Eric T., et al.

It’s thought that endurance training improves insulin sensitivity by enhancing glucose disposal. While the effect of resistance training is probably due to increased lean mass over time.

In addition, training raises catabolic hormones that break down your body. Then prime your body to release anabolic hormones like insulin in order to start building back up.

Therein lies the key to body transformation.

How Insulin Transforms Your Body

At this point, it may seem like insulin is bad or that you should keep it as low as possible.

However, insulin is a cycle of catabolic and anabolic processes. While catabolism breaks things down, anabolism builds things up. Both are necessary.

how insulin regulates fat loss and muscle gain

 So it’s important to understand, raising insulin is just as important as lowering it.

The key is balancing the rise and fall based on your health and fitness goals.

When your goal is burning fat, it’s best to keep insulin low for the majority of the day (below the red line). Except after resistance training workouts, when raising insulin prevents your muscles from breaking down.

daily insulin level by goal

On the other hand, it’s beneficial to keep insulin higher throughout the day if your goal is gaining muscle (above the red line). As long it’s not chronically elevated above the healthy threshold (green dashed line).

In addition, it’s possible to burn fat and build muscle at the same time by balancing between catabolic and anabolic. Also known as body recomposition.

How to Burn Fat & Build Muscle At The Same Time

The key to controlling your insulin levels throughout the day is carb intake and meal timing.

daily feeding-carb cycle by goal

Altogether, this information can be overwhelming. That’s why Nutritioneering provides meal plans designed with insulin balance built in.

With a custom meal plan, your macros and meal times are set up to optimize blood sugar levels based on your body type, activity level, schedule, and goals.

Click Here To Customize Your Plan

Key Takeaways

  • Insulin is like a valve that lets energy enter your cells
  • Proper function is vital for overall health and fitness
  • A high protein, low carb diet plus exercise improves function
  • Balancing levels is the key to body transformation


Overall, insulin is the most powerful hormone in your body. When it functions properly and you keep it under control, you will transform your body.

But did you know there are other hormones that work together with insulin? Two such hormones are ghrelin and leptin.

Click the links below to learn about how they control your hunger and appetite.

Share with your community and get the conversation started!

Go to Top