If you’re insulin sensitive your body processes and uses glucose well and thus you can use carbohydrates in a diet. If you’re insulin resistant, your body does not process and absorb glucose well and is carbohydrate intolerant and low-carb diets will work the best for you (low-carb, high-fat and enough protein).
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. Insulin resistance may also damage your blood vessels without you realizing it. 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 mid section
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 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 4 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, PhD and Stephen Phinney, MD, Phd, “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 carbohydrate 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
There seems to be various degrees of insulin resistance. Insulin does it’s job and then overtime 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 an 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.
Evidence in Blood Work
If you don’t have obvious symptoms, you’re insulin resistance, pre-diabetes, and diabetes are usually detected with a blood draw.
One way to diagnose pre-diabetes or diabetes is with an A1C test. This test measures your average blood sugar over the past two to three months.
- An A1C under 5.7 percent is considered normal.
- An A1C between 5.7 and 6.4 percent is diagnostic for pre-diabetes.
- An A1C equal to or above 6.5 percent is diagnostic for diabetes.
Your doctor may want to reconfirm this test on another day. However, depending on the lab where you have your blood drawn, these numbers could vary anywhere from 0.1 to 0.2 percent.
Fasting Blood Glucose Test
A fasting blood glucose test is taken after not eating or drinking for at least eight hours. It provides your fasting blood sugar level. It can be performed at home using a meter, like the one shown above from Abbot Labs (Precision Xtra model).
A high level may require a second test a few days later to confirm the reading. If both tests show elevated levels of blood glucose, you may be diagnosed with pre-diabetes or diabetes. If you do test at home please notified your doctor of your results.
- Fasting blood sugar levels under 100 mg/dL are considered normal (the meter shown above shows the results of recent test I did at home with a blood glucose reading of 82 mg/dL²).
- Levels between 100 and 125 mg/dL are diagnostic for pre-diabetes.
- Levels equal to or greater than 126 mg/dL are diagnostic for diabetes.
Again, depending on the lab, these numbers could vary up to 3 mg/dL points in the cutoff numbers.
Random Blood Draws
You can also have your blood glucose levels checked at any time of day. For these “random” blood draws:
- blood sugar levels under 140 mg/dL are considered normal²
- levels between 140 and 199 mg/dL are considered prediabetes
- levels equal to or over 200 mg/dL are diagnostic for Type 2 diabetes
Earlier testing may be recommended if you are overweight and you:
- live a sedentary lifestyle
- have low good (HDL) levels or high triglyceride levels
- have a parent or sibling with diabetes
- are American-Indian, African-American, Latino, Asian-American, or Pacific Islander
- have high blood pressure (140/90 mm Hg or above)
- have symptoms of insulin resistance (see above)
- were diagnosed with gestational diabetes (a temporary condition that develops while pregnant)
- had a baby who weighed more than 9 pounds
¹ Volek, Jeff; Phinney, Stephen. The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable
² I didn’t own the meter prior to starting a low-carb diet. I had all of the symptoms listed for insulin resistance. After I was on my low-carb diet for about 2 weeks is when I acquired a meter and started testing my fasting blood sugar and ketone levels. My readings have been taken at various times during the day; in the morning, before a workout, days I’ve intermittent fasted, after a workout and in the evening. I’ve averaged 78.4 as of June 13, 2007. This is what I would expect because I only consume about 35 grams of carbohydrate a day and my insulin levels would be low while I’ve been in a constant state of ketosis since April 3, 2017.