You’ve probably heard about Insulin Resistance. It is now understood to be a major factor in many of our modern diseases. Diabetes, heart disease, stroke, cancer, Parkinson’s, Alzheimer’s, overweight and obesity – all are correlated with higher fasting insulin, and insulin resistance. Let’s explore what insulin in, and how to tell how likely it is that you are insulin resistant.

What is Insulin?

Insulin is a hormone that acts like a key, opening up our cells to take in sugar from the blood. Insulin is made in the pancreas, an organ located behind the stomach that contains clusters of cells called islets. Inside the islets are beta cells, and these are what produce insulin and release it into the blood. Insulin is released when we eat (or just think about eating), to remove sugar from the blood and put it into cells for use as current or future fuel.

A Spoonful of Sugar

When we consume foods and caloric beverages, the digestive tract breaks down any carbohydrates—sugars and starches—in those foods and beverages into glucose. That glucose then enters the bloodstream; this is what we refer to as “blood sugar”.

Our bodies work to tightly control the level of sugar in our blood at all times, aiming to keep it at about 4/5 of a teaspoon (~4 grams) throughout our entire ~5 liters of blood.

Fun fact: 4g of sugar in 5 liters of blood correlates with a blood glucose reading of ~80 mg/dl.

When blood glucose rises above ~80 mg/dl, the body acts very quickly to remove some sugar from the blood and get it into cells, since it is caustic and damaging if left circulating in the blood.

To get sugar out of the blood, insulin carries it to our cells, and acts like a key, opening our cells to let the sugar in. However, the ability of cells to use or store sugar is finite; at some point, our cells get “full”, just like our bellies.

When we consistently consume more carbohydrates than our cells can quickly use, over time the cells start to ignore insulin when it comes bearing its sugary gifts. The cells refuse to open up and let more sugar in. So our pancreatic beta cells pump out more insulin to try to force the cells to open up and take in the sugar. This works for a while, but then the cells stop listening again, so the body makes more insulin. And round and round it goes.  

The cells are like teenagers – the more and louder you yell at them to clean up their room, the more they ignore you!

This situation of elevated insulin production and increased cell resistance to insulin’s influence is what we call Insulin Resistance (IR). As the cells get more and more resistant, the body has a harder and harder time clearing glucose from the blood, which leads to higher and higher blood sugar levels over time, which leads to a whole host of health problems.

Are You Insulin Resistant?

There are several relatively easy-to-obtain measurements that you can consult to determine the likelihood that you are insulin resistant, and to roughly what degree.

(A big thanks to Dr. Georgia Ede of, and to, for the info below.)

Test                                                     Results

Fasting Blood Glucose (BG)               <85 mg/dl is ideal                              IR unlikely

                                                            90-100 = future diabetes likely           IR likely

                                                            101-119 = pre-diabetic                        IR almost certain

                                                            120+ = diabetic                                   IR certain

A1C (90 day BG avg)                         4.5 is optimal                                      IR very unlikely

                                                            4.6 – 5.0 is excellent                            IR very unlikely

                                                            5.0 – 5.4 is good                                   IR possible

                                                            5.5 – 6.4 is pre-diabetic                       IR almost certain

                                                            >6.4 = diabetic                                    IR certain

Post-Prandial                                      <100 mg/dl is optimal                        IR less likely

Blood Glucose                                     101-140 is good                                   IR possible

(2 hours after meal)                            140-199 = pre-diabetic                        IR almost certain

                                                            >200 = diabetic                                   IR certain 

Fasting Triglycerides (TG)                  <100 mg/dl is optimal                        IR less likely

(fat in the blood)                                 100-150 is good                                   IR somewhat likely

                                                            >150 = problematic                            IR very likely 

HDL (“good cholesterol”)                  >40 mg/dl for men is good; >50 is optimal

                                                            >50 for women is good; >60 is optimal

Lower HDL, esp coupled with elevated TG, typically corresponds with more small dense LDL particles (bad) and IR

 Ratio of TG:HDL

<3.0 mg/dl (or <1.2 mm/L) is good   IR less likely

>3.0 is problematic                           IR likely 

Waist Index

<1.15 is good                                       IR unlikely

>1.15 problematic                              IR likely

To calculate waist index:

Men: waist circumference (cm) / 94

Women: waist circumference (cm) / 80

HsCRP                                                <1 mg/dl is good                                IR unlikely

(highly sensitive                                 >1 problematic                                   IR likely

C-reactive protein)

Uric Acid                                           

  • <6 mg/dl in men is good
  • <5 mg/dl in women is good

Elevated serum uric acid is one of the best independent predictors of diabetes and commonly precedes the development of both IR and diabetes

Calculating Your Insulin Resistance

You can also use a formula involving just your fasting glucose and triglyceride test results to get a pretty good idea of whether you are insulin resistant or not.

Simply multiply your fasting blood glucose (in mg/dl) by your fasting triglycerides (in mg/dl), and divide this number by 2. Then take the natural log of this number.

                        LN* [(Fasting Blood Glucose x Fasting Triglycerides)/2] 

* Natural Log – go to for calculator 

Men with a result >8.82 and women with >8.73 are very likely insulin resistant, and have a much higher risk of developing Type 2 Diabetes in the future. 

Last But Not Least 

And, if you have the option of getting a Fasting Insulin test, here’s what the results mean:

  • <5 mU/L is good
  • 9-13 mU/L means IR likely
  • >13 = IR certain

 Now What?

Now that you have a better idea of your probable level of insulin resistance, if the results are less than ideal, it’s time to start lowering your carb intake and doing some intermittent fasting. The sooner you begin, the sooner your health will improve, for the short and the long term.

And if you’ve already made Keto your lifestyle, good for you! Give it time to work its magic; after several weeks to months, your insulin resistance will begin to fade away and be replaced by insulin sensitivity, your blood sugar levels will fall to healthier levels, and your risk of all sorts of scary diseases will drastically reduce.