How is Insulin Like Japanese Subway Train Pushers?

Insulin is the hormone that transports the fuel glucose (aka blood sugar) into a working muscle while at the same time instructing the body to not use fat as fuel. 

When the muscle cells are already full of glucose the body, in an attempt to protect the liver, introduces more insulin from your pancreas to shove as much of the blood sugar into already packed cells. When the muscle cells are completely full of glucose and an enormous amount of insulin is floating around in your blood, your liver has one job to protect you from the ill effects of hyperglycemia (high blood sugar) and it stores the excess blood sugar into your fat. 

Thus, insulin is like Japan subway pushers, shoving way more passengers in the cars than the cars were designed to handle.

When this happens in your body, the cells are resistant to more insulin, just like passengers are resistant to being shoved in an overcrowded subway car.

If you’re insulin sensitive, on the other hand, the cars have not yet full and passengers gladly accept help from the station attendants and walk into the cars. When your cells are not already packed full of glucose, insulin can easily do its job to transport the glucose to where it is needed.  Therefore if you're insulin sensitive, your body processes and uses glucose well and thus you can use carbohydrates in a diet. Subway passengers come from carbohydrates (i.e., glucose, or blood sugar, is created from carbohydrates.  If you’re insulin resistant, your body does not process and absorb glucose well (because your cells are already packed full of blood sugar) and is carbohydrate intolerant and low-carb diets will work the best for you. Just like if there were not as many passengers riding the subway in Japan, they wouldn't need as many subway pushers.

The Symptoms of Insulin Resistance

Insulin resistance often doesn’t trigger any noticeable symptoms, especially in the early phases. You could be insulin resistant for years without knowing, especially if your blood glucose levels aren’t checked (i.e, the Japan subway authority were lax on recording the number of subway passengers relative to the number that the system can handle). Insulin resistance may also damage your blood vessels without you realizing it (can you imagine the damage to the rail cars with so many passengers riding every day). This can increase your risk of heart disease and stroke.

If you have insulin resistance, you’re at significant risk for progressing to diabetes.

The symptoms of type 2 diabetes can be mild, so you may not know you have the condition until a doctor runs diagnostic tests on you. Classic diabetes symptoms include:

• extreme thirst or hunger
• feeling hungry even after a meal
• frequent or increased urination
• tingling sensations in your hands or feet
• feeling more tired than usual

Symptoms you may be insulin resistance before the onset of pre-diabetes, diabetes or metabolic syndrome may include:

• tend to be thirsty or hungry
• feel hungry after a meal
• carbohydrate cravings at usual times during the day (mostly evening hours)
• steady weight gain especially after your mid-forties
• calorie restricting diets don’t seem to work like they used to
• the onset of more inflammation
• frequent urination at night after you’ve gone to bed
• energy peaks and valleys throughout the day
• you carry your excess weight in the midsection

What is Insulin Resistance?

Dr. Frederick Banting discovered insulin in 1922 and was awarded a Nobel Prize one year later. You would have predicted then that science would have actually figured out how insulin works by now. However here we are almost a hundred years later with no real answers how it works.

Here is what science does know:

Insulin binds to a cell’s receptor (discovered in 1969) allowing glucose to be transferred from blood to inside the cell to be used as fuel. Without that action and completion of the insulin doing this important function, glucose is stuck floating around in the fluid outside your cells. “And in fat cells, stimulating the same receptor [does just the opposite, it] shuts off the fat release and promotes fatty acid uptake, triglyceride synthesis, and fat storage.”¹

“In the 1930s is when scientists began observing that some people with high blood insulin levels seemed to be oblivious to its signal. Thus was born the concept of insulin resistance, broadly defined as a diminished ability of insulin to exert its normal biologic effect on a cell.” ¹

It is estimated that 1 in 2 adults in the U.S are insulin resistant and therefore do not have predictable success on diets that contain higher levels of carbohydrates.

Carbohydrate Increases Insulin

According to Jeff Volek, Ph.D. and Stephen Phinney, MD, Ph.D., “The primary stimulator of insulin release from the pancreas is dietary carbohydrate.” ¹

They also say, “If you consume a high carbohydrate diet, particularly one with a lot of rapidly digested sugars and refined starches, your body has an increased dependency on insulin to maintain normal metabolic homeostasis. Specifically, the insulin released after a high carbohydrate meal is necessary to simultaneously inhibit glucose output from the liver and promote glucose uptake by skeletal muscle. Failure of insulin to perform either of these tasks, such as occurs in insulin resistance, will lead to elevated blood sugar (hyperglycemia). What this means is that when carbohydrate intake is high it puts an increased pressure on insulin to do its job effectively. If you’re insulin sensitive, great – you can probably tolerate lots of carbohydrates and not run into metabolic problems. However, if insulin is struggling to perform its duties, increased consumption of carbohydrate just exacerbates an already broken system.” ¹

Various levels of Insulin Resistance

A combined blood glucose and ketone meter

There seem to be various degrees of insulin resistance. Insulin does its job and then over time, you become less able to process glucose and the resistance increases. The only way to know for sure is to have medical tests done although some simple tests you can do at home with simple blood sugar testing devices may give you clues if you also have the symptoms listed above. Some of these methods are explained below.

Methods to Determine if You’re Insulin Resistant

Disclaimer: Only a licensed health care practitioner can diagnose if you are insulin resistant. We recommend you seek their evaluation.

There are several methods used to assess if you are insulin resistant. The most notable is a method called an insulin clamp. It is complex, time-consuming, invasive, and puts the person at risk of low blood sugar (hypoglycemia).

A much simpler method is to simultaneously measure blood glucose and blood insulin levels and estimate insulin sensitivity using a homeostatic model assessment.

Insulin resistance is the hallmark of metabolic syndrome and Type-2 diabetes.

Insulin resistance helps explain why most type-2 diabetics are overweight or obese because their fat cells are constantly maintained in storage mode by their high levels of insulin.