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Insulin Sensitivity – The Ultimate Guide and 10 Ways To Optimize It

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Insulin sensitivity describes an extremely complex and important metabolic process within the body that regulates how we digest and utilize carbohydrates.

Insulin sensitivity is commonly associated with carbohydrate “tolerance” and utilisation. In essence, the more insulin sensitive someone is, the more efficient they will be at utilizing carbohydrates.

Additionally, insulin sensitivity also regulates how one sets up their diet in order to ensure progress and success.

In short, good insulin sensitivity means increased health, muscle gain and fat loss. Find out why and how to improve it in this Insulin Sensitivity Ultimate Guide

Basics of Insulin Sensitivity & Insulin Function

Insulin is a key hormone secreted from the pancreas in response to food, primarily carbohydrate or protein.

Insulin’s main function is to regulate the body’s blood glucose (sugar levels), which must stay within a narrow margin. When blood glucose and insulin function become dysfunctional, it can lead to diabetes, weight gain, energy changes, an inability to grow muscle, increased risk of disease and a host of metabolic issues.

Insulin is often termed a “Master regulator” or “Master Hormone.” Whenever you eat food, insulin levels rise and drive nutrients to various tissues in the body.

In the case of healthy individuals or athletes, these nutrients are directed to the muscle for energy, glycogen (stored carbs) replenishment, recovery and growth. However, many people who have poor insulin sensitivity, also known as insulin resistance, can lead to fat accumulation and even disease such as Type 2 Diabetes.

Insulin resistance typically refers to the body’s  inability to utilize insulin as it should. Although insulin resistance is actually very common, the severity of resistance varies greatly between individuals.

Insulin Sensitivity

Insulin Resistance, Fat Loss and Your Physique

If you are overweight or struggle with carbs, then the chances are you have got some degree of insulin resistance.

For such an individual, having big carbohydrate meals such as pasta and large amounts of bread can have adverse reactions such as sleepiness, brain fog and general fatigue.

Aside from the long-term health issues, insulin resistance can also lead to difficulty losing body fat and maintaining energy levels.

As you can see, insulin sensitivity / resistance is extremely important, especially if you care about building muscle or losing body fat.

For fat loss, having greater insulin sensitivity may allow you to more easily and effectively lose body fat and build lean muscle mass, while allowing for greater flexibility when it comes to the different foods you wish to enjoy.

In terms of fat accumulation, when you are insulin resistant it causes an excess amount of blood sugar to be left in the bloodstream. This is bad news, as it is actually dangerous after a long period of time and therefore the body has no choice but to remove it. When insulin doesn’t function correctly, the next route the body takes is to remove that blood sugar and store it in the dreaded fat cells.

So, while carbohydrates alone don’t cause you to gain fat, if you eat an excess amount and are insulin resistant then it can lead to extra fat gain, which is one reason people think ‘carbs make you fat’. Hopefully you can now see, it’s not the fault of the carbs themselves but your body’s (in)ability to utilize them, based on your insulin function.

This is just one reason why some of your friends can eat pasta, cake or ice cream daily, while you may gain fat just by looking at a bowl of pasta or loaf of bread.

Insulin Sensitivity Basics

Insulin is a master hormone that regulates how the body responds to and digests different foods such as carbohydrate and proteins.

Ensuring that insulin sensitivity is high is essential for proper responses to different foods, in addition to a wide range of health metrics.

While insulin sensitivity is especially important for athletes, it’s just as important for individuals hoping to improve body composition by losing body fat and gaining lean muscle tone. In essence, insulin sensitivity is just as important for an office worker as it is for a bodybuilder about to do a photoshoot.

Fortunately, proper sleep, nutritional habits, exercise routine and effective supplementation all significantly impact insulin sensitivity. Ensuring proper balance of all of these factors is essential for health.

Now you understand insulin sensitivity (good) and insulin resistance (bad) it’s time to learn how to actually boost and optimize insulin sensitivity, while reducing insulin resistance!

insulin sensitivity

How to Improve Insulin Sensitivity Backed By Science

1. Metabolic Weight Training

Weight training has been shown to be one of the best ways to improve insulin sensitivity. One of the ways it does this is that muscle contraction leads to transporters in the muscle cell being moved to the cell’s membrane (1, 2, 3).

In doing so, glucose more readily enters muscle cells rather than being stored and converted to fat.

2.  Metabolic HIIT Training

Just 2-3 short and intense 10-minute HIIT sessions can quickly improve insulin sensitivity (4).

I suggest adding progressively increasing HIIT protocols into your weekly training program, evenly spaced throughout the week.

If you want to get started, you can get my 30 Day HIIT Program here for just $15.

3. Use Carb or Carbohydrate Cycling

Carb cycling is one of my favourite techniques that allows you to moderate the amount of carbohydrates you are consuming in relation to your daily activity levels.

This means that on days when you have your biggest, highest volume workouts, you consume greater amounts of carbohydrates than on days when you do less exercise.

Following this method allows you to ensure that you are only consuming carbs when you need them. Doing so can significantly improve insulin sensitivity.

Learn more about Carb Cycling in this blog post.

4. Use Lower Carbohydrate Periods Throughout The Year

Adding in some low carb weeks throughout the year may help you optimize insulin sensitivity by improving metabolic flexibility and reducing the continued strain of a higher carb diet on your insulin function.

Over years, overconsumption of carbohydrates leads to chronic elevations of insulin, which ultimately results in insulin resistance, especially if you also have excess body fat levels.

Having periods of low carbs allows for insulin to be reduced, leading to greater sensitivity and probably also to better metabolic health in the long term. To do this, you could perform a typical 3 month higher carb diet then follow that with a 1 month lower carb and calorie diet to burn some body fat and improve insulin function.

Get my 7 Day Ketogenic Low Carb Meal Plans here.

5. Train In A Glycogen-Depleted (Low-Carb) State

Lots of research has shown that exercise, (particularly cardio), in a fasted state upregulates mitochondrial adaptations by generating greater amounts of mitochondria.

By having greater amounts of mitochondria, your body is better equipped to utilize fat as fuel and, as a result, improves insulin sensitivity (5).

This helps boost your metabolism so it burns more energy and improves both insulin sensitivity and health.

To apply this advanced scientific technique, try performing cardio, when fasted in the AM, before breakfast.

6. Take 3g Of High Strength EPA & DHA Omega 3 Fish Oil

While fish oil is essential for cardiovascular and brain health, regular supplementation can also improve insulin sensitivity (6).

I suggest taking fish oil daily along with a meal to avoid potential gastrointestinal distress. Aim for 3g of high quality fish oil with around 600+ EPA/DHA per 1 gram.

If you are in the USA, you can get this high strength fish oil at a reduced price of just $19 here

insulin sensitivity

7. Add In 30-50mg Of Zinc Per Day

Zinc is a key mineral responsible for an array of metabolic and physiological processes within the body, one of which is to improve insulin sensitivity, so make sure it’s in your supplement regime (7).

Try taking about 30-50mg of Zinc per day – this can be taken with any meal or at night as part of ZMA supplement.

8. Improve Your Sleep

Everyone should know about the importance of sleep. Regular and sufficient sleep has been shown to improve insulin sensitivity, whereas poor sleep can make you insulin resistant (8).

By having a proper sleep-wake cycle, you can begin to optimize how your body responds to food from a hormonal standpoint.

Focus on getting a deep, 7-8 hours of sleep per night.  You can also learn how to optimize your sleep in this blog post.

9. Chill Out & Reduce Stress

Similar to sleep, ensuring proper management of stress is essential for overall health and insulin sensitivity.

Chronic elevations of cortisol, the stress hormone, can cause health issues, muscle loss, fat storage, depression, anxiety and hormonal disruption. While acute increases of cortisol are necessary for a variety of reasons, chronic elevations can make you less insulin sensitive and can lead to insulin resistance (9).

Ensure that you moderate stress levels to help improve insulin sensitivity and overall health / wellbeing.

10. Supplement With 5000iu Of Vitamin D3, L-Carnitine & Resveratrol

Finally, these additional supplements can provide an array of health benefits and will work to improve insulin sensitivity.

Vitamin D3 is extremely cost effective and has an array of benefits. Resveratrol is the compound found in wine that gives it the proposed health benefits. The only difference is the supplement is about 50x stronger and without the calories in wine. Lastly, L-Carnitine can also be beneficial for insulin function; however, it comes last on the list after the first 2 and Zinc / Omega 3 we discussed above.

Make sure you’re adding these into your regime to improve general health, reduce risk of disease and to improve insulin sensitivity (10, 11, 12).

Insulin Sensitivity – The Ultimate Guide

There you have an ultimate guide on the basics of insulin, how it works, why it’s important and 10 advanced, research proven methods on how to improve it.

You can learn more many of the techniques included in my 90 Day Bikini Transformation Plan or go lower carb, with my Advanced Metabolic Ketogenic Diet plan.


  1. Ishii, T., Yamakita, T., Sato, T., Tanaka, S., & Fujii, S. (1998). Resistance training improves insulin sensitivity in NIDDM subjects without altering maximal oxygen uptake. Diabetes care, 21(8), 1353-1355.
  2. Ju, J. S., Smith, J. L., Oppelt, P. J., & Fisher, J. S. (2005). Creatine feeding increases GLUT4 expression in rat skeletal muscle. American Journal of Physiology-Endocrinology and Metabolism, 288(2), E347-E352.
  3. Watson, R. T., & Pessin, J. E. (2006). Bridging the GAP between insulin signaling and GLUT4 translocation. Trends in biochemical sciences, 31(4), 215-222.
  4. Jelleyman, C., Yates, T., O’Donovan, G., Gray, L. J., King, J. A., Khunti, K., & Davies, M. J. (2015). The effects of high‐intensity interval training on glucose regulation and insulin resistance: a meta‐analysis. Obesity reviews, 16(11), 942-961.
  5. Cantó, C., Jiang, L. Q., Deshmukh, A. S., Mataki, C., Coste, A., Lagouge, M., … & Auwerx, J. (2010). Interdependence of AMPK and SIRT1 for metabolic adaptation to fasting and exercise in skeletal muscle. Cell metabolism, 11(3), 213-219.
  6. Storlien, L. H., Kraegen, E. W., Chisholm, D. J., Ford, G. L., Bruce, D. G., & Pascoe, W. S. (1987). Fish oil prevents insulin resistance induced by high-fat feeding in rats. Science, 237, 885-889.
  7. Faure, P., Roussel, A., Coudray, C., Richard, M. J., Halimi, S., & Favier, A. (1992). Zinc and insulin sensitivity. Biological trace element research, 32(1), 305-310.
  8. Buxton, O. M., Pavlova, M., Reid, E. W., Wang, W., Simonson, D. C., & Adler, G. K. (2010). Sleep restriction for 1 week reduces insulin sensitivity in healthy men. Diabetes, 59(9), 2126-2133.
  9. Rizza, R. A., Mandarino, L. J., & Gerich, J. E. (1982). Cortisol-induced insulin resistance in man: impaired suppression of glucose production and stimulation of glucose utilization due to a postreceptor defect of insulin action. The Journal of Clinical Endocrinology & Metabolism, 54(1), 131-138.
  10. Gedik, O., & Akahn, S. (1986). Effects of vitamin D deficiency and repletion on insulin and glucagon secretion in man. Diabetologia, 29(3), 142-145.
  11. Günal, A. I., Celiker, H., Dönder, E., & Günal, S. Y. (1998). The effect of L-carnitine on insulin resistance in hemodialysed patients with chronic renal failure. Journal of nephrology, 12(1), 38-40.
  12. Brasnyó, P., Molnár, G. A., Mohás, M., Markó, L., Laczy, B., Cseh, J., … & Mészáros, L. G. (2011). Resveratrol improves insulin sensitivity, reduces oxidative stress and activates the Akt pathway in type 2 diabetic patients. British Journal of Nutrition, 106(3), 383-389.


About the author

Rudy Mawer, MSc, CISSN

Rudy has a 1st class BSc in Exercise, Nutrition & Health and a Masters in Exercise & Nutrition Science from the University of Tampa. Rudy currently works as a Human Performance Researcher, Sports Nutritionist and Physique Coach. Over 7 years he has helped over 500 people around the world achieve long last physique transformations.

He now works closely with a variety of professional athletes and teams, including the NBA, USA Athletics, World Triathlon Gold Medalists, Hollywood Celebrities and IFBB Pro Bodybuilders. If you would like to get in contact or work with Rudy please contact him on social media.

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