Insulin: How it affects Fat Loss and Muscle Gain

Insulin Hormone Diagram

When it comes to fat loss, this is the mother of all hormones.  After a meal, this hormone is secreted from the pancreas and signals to your cells in your liver, fat, and muscles to take in nutrients.  Timing your insulin spikes can control whether nutrients are stored in fat cells or stored in muscle.

For example, after a resistance training workout, your insulin sensitivity is increased and your cells are primed to uptake nutrients in muscle rather than fat.  By strategically planning on having the majority of your carbs after a workout you enable your body to tolerate more carbs. You see, your muscles have a form of glucose in them, glycogen.  When working out, your muscles tap into your glycogen stores for fuel. After a hard workout, your muscles become glycogen depleted. Muscles that are glycogen depleted make you more insulin sensitive because there is more “room” for carbs in the muscle.  If you’re insulin sensitive, the foods you eat get stored more readily into muscle and not fat.  

What is insulin sensitivity?

Insulin sensitivity is defined by how much insulin is required to store glucose in our cells. If you are very insulin sensitive you require only a small amount of insulin to store glucose in the blood into your cells. Insulin individuals require more insulin to store the same quantity of glucose.

If you have a low insulin sensitivity (insulin resistant), then you’re going to have excess glucose in your blood. This means more insulin must be dumped into the bloodstream to remove the extra glucose.

If you are insulin resistant the foods you eat will be more readily stored into fat and not into muscle. Insulin resistance can result from a host of different reasons, but here are the main ones:  Chronic inflammation, poor sleep, not enough movement throughout the day, limited cold exposure, a diet high in processed sugar and carbs, and not enough strength training. 

When you are insulin resistant you have higher circulating levels of blood sugar for a prolonged amount of time.  This is because after eating a meal, the nutrients and carbs cannot be stored in the muscle as efficiently as someone who is more sensitive.  The carbs which have been converted into glucose, stay in your bloodstream and cause blood sugar levels to be elevated. Your nutrient transport system is backed up and your body diverts nutrient storage into fat cells because it is ineffective at storing nutrients into the muscle (1).  This also prevents your muscles from growing because amino acids, the building blocks of muscle, have trouble getting into the muscle.  

Insulin resistance doesn’t just make you fat, it also causes you to lose muscle. After someone who is insulin resistant has a large meal their body is not able to properly supply the rest of the body with adequate energy from that meal.  Your body is essentially starving even though you have just eaten. Your body searches for the next best energy source to produce glucose: your own muscle. That’s right, your body starts eating away at its own muscle mass to help fuel itself even though there is energy available from the food you just ate!.  The process is called gluconeogenesis. Gluconeogenesis breaks down the protein in your muscles and converts it into glucose for energy. Chronic high levels of insulin make you fat and steal away your muscle.  Besides being terrible for body composition, chronic high levels of insulin are not healthy and will eventually lead to either diabetes or another type of metabolic syndrome.

How to Improve Insulin Sensitivity/Control Blood Sugar:

Ok so we know that spiking your blood sugar levels is bad and can result in insulin insensitivity, so what are some of the ways to mitigate this problem?

The #1 strategy for reducing blood sugar levels is strength training. We touched on this a bit at the beginning of this article. When you strength train you deplete muscle glycogen. Once muscle glycogen is depleted, you can eat carbs and those carbs will be partitioned into the muscle to restore those glycogen levels.

#2. Fasted Cardio

According to this article, researchers in Belgium discovered that performing exercises in the morning before breakfast increases energy metabolism for the rest of the day when compared to the control study group that exercised after eating.

#3. Take a post-meal walk

A Japanese study discovered that taking a 30-minute walk after a meal was able to reduce fat in the participants’ blood by 18%!(7)

#4. Cut out Fructose

According to numerous studies, fructose is the main culprit in table sugar that causes insulin resistance, not glucose. In animal models, fructose produced the following responses: insulin resistance, impaired glucose tolerance, high insulin levels, high triglycerides, and hypertension.

#5. Stop Eating Trans Fats

Trans fats are horrendous for overall health. So you should just stop eating immediately regardless of what they do to your body composition. Trans fats have been shown to inhibit glucose disposal, promote insulin resistance, and induce abdominal obesity.(3)

# 6. Drink Green Tea

This study showed that green tea is able to cause carbohydrates to be partitioned into muscle rather than body fat via the translocation of glucose transporter 4 (GLUT4) from adipose tissue to skeletal muscle.(5) Thus, more carbs are being stored into muscle and not into fat storage. Sounds like a win!

#7. Improve Omega 3/6 Fatty acid ratio

Not only will improving your Omega 3 to 6 fat ratio reduce the amount of inflammation in your body, but it will also help improve your insulin sensitivity.(3). Check out this article HERE to take a deeper dive into fatty acid nutrition.

#8. Utilization of Spices and Herbs

One of the best spices for reduces blood sugar levels is Cinamon. Putting a little bit in your morning coffee can help to blunt the side effects of blood sugar. Other spices that have the same blood sugar lowering effect are Berberine, bitter melon extract, and rock lotus.


  1. Bastard, J., P. et al Recent advances in the relationship between obesity, inflammation, and insulin resistance . Eur Cytokine Netw. (2006)
  2. Thresher et al, Comparison of the effects of sucrose and fructose on insulin action and glucose tolerance. AJP- Regu Physiol October 2000 vol.279 no.4
  3. Kavanagh et al, Trans fat diet induces abdominal obesity and changes in insulin sensitivity in monkeys. Obesity 2007 Jul;15(7):1675-84.
  4. Gonzalez-Periz et al, Obesity-induced insulin resistance and hepatic steatosis are alleviated by omega-3 fatty acids: a role for resolvins and protectins. FASEB J. 2009 Jun; 23(6):1946-57
  5. Ashida et al, Anti-obesity actions of green tea: Possible involvements in modulation of the glucose uptake system and suppression of the adipogenesis-related transcription factors. Biofactors 2004; 22(1-4):135-40.

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