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Sugar’s Slippery Slope: Insulin Sensitivity and Type 2 Diabetes

Sugar’s Slippery Slope: Insulin Sensitivity and Type 2 Diabetes

Alarmingly, the body can be unintentionally trained into a diabetic state. As more and more sugars are taken into the diet, certain mechanisms are triggered that become stronger and more ingrained until type 2 diabetes can be diagnosed. The good thing is what can be trained into the body can also be undone, though it may take some effort.

Diabetes and pre-diabetes caused by blood sugar dysregulation continue to climb in the United States, with about 40% of the population affected, roughly 130+ million people (1, 2). This is why we at Temecula Center for Integrative Medicine continually emphasize education, prevention, and functional medicine treatments for many blood sugar-related conditions, including diabetes, pre-diabetes, and insulin resistance. Please see our article entitled “Insulin Resistance, Diabetes, and Functional Medicine” for a good grounding in those health conditions.

The purpose of this article is not to repeat the excellent information of our previous article. Rather, the aim is to focus on some of the mechanisms that make diabetes possible and how to use that knowledge to decrease the risk of dysregulated blood sugar conditions in the first place.

Decreased insulin sensitivity → insulin resistance → prediabetes → Type 2Diabetes

Carbohydrates such as sugars in the diet are converted by the liver into glucose and released into the bloodstream. The glucose concentration in the blood is also known as “blood sugar.“ The cells in tissues of the human body need some glucose, which they use as fuel, but it’s rather dangerous to the body to have too much or too little. There are many mechanisms in place that the body uses to regulate the amount of glucose in the bloodstream.

Insulin is a hormone created by the pancreas. One of insulin’s “jobs” is to help get glucose across a cell membrane and into a cell. Glucose cannot enter a cell at all without the presence of insulin. A mental picture that can be used is that of insulin “knocking” at the door of the cell, and when the cell “sees” the insulin and glucose there, it allows the glucose across the cell membrane and into the interior of the cell. The cell can then degrade the insulin, or allow the insulin to make its way to the liver or kidneys. The glucose is then either utilized or stored.

Insulin sensitivity” is a term that describes how efficiently the cells in a body respond to insulin. Having a high sensitivity would mean that the cells are very responsive to the insulin, and easily allow the insulin to tuck the glucose into the cell, across the cell membrane. Low sensitivity to insulin is considered an impairment, where the cell is not very responsive to the presence or the action of the insulin, leaving the rejected glucose to linger in the bloodstream. This mechanism can get stuck in an impaired, low-sensitivity state that can cascade into a feedback loop that ends in the diabetic state.

The next step into the damaging feedback loop is “insulin resistance.” It is also known as “impaired insulin sensitivity” (3). This is an abnormal state of consistently weak insulin sensitivity that can be diagnosed by the amount of circulating glucose in the blood, the hemoglobin A1C blood test, and symptoms. (Some labs will also measure circulating insulin and several other factors in the serum to come up with an “insulin resistance” (IR) score.)

It is thought that chronically low insulin sensitivity contributes to insulin resistance, and certainly, insulin resistance is characterized by low insulin sensitivity. However, note that many factors can contribute to insulin resistance besides low insulin sensitivity, including diet, exercise, and genetics.

When insulin resistance is high, glucose stays in the bloodstream longer, and the body’s response is to make more insulin because the beta cells in the pancreas sense there is still glucose in the bloodstream that needs to be tucked into cells. The state of chronically high insulin is called hyperinsulinemia. If the pancreas’s release of insulin can stay on top of regulating the glucose levels, keeping the concentration of glucose in the blood in a narrow range, all is well.

However, if the system keeps getting overwhelmed with glucose (as from the diet), it can lead to hyperglycemia – the state of a consistently high amount of glucose in the bloodstream. Insulin and glucose are now bombarding the cells. Imagine that many cells, being overwhelmed, hear the insulin knocking at the door, but won’t open the door to let the glucose in, as they’ve already had enough glucose. At this point, eating more carbohydrates (sugars) simply compounds the hyperglycemic state. Chronic states of hyperglycemia and hyperinsulinemia both increase the risk of pre-diabetes and, eventually, diabetes.

The diagnosis of pre-diabetes has been utilized in the last few decades as the red flag for intervention to arrest the march toward full-blown diabetes. A hemoglobin A1C score of 5.7 – 6.4 is considered pre-diabetes. Interestingly, glucose is sticky, like honey, and sticks to the outside of red blood cells (RBCs). The hemoglobin A1C test reflects an average of how glucose-covered the RBCs are in the blood sample. RBCs have a lifespan of about 3 months. Every moment, new RBCs are made and old ones are destroyed and recycled, so any blood sample contains a mixture of different ages of RBCs. By giving the average of how sugar-coated the RBCs are, the hemoglobin A1C score roughly reflects how much sugar has been in the person’s diet over the last few months. While the glucose score will go up and down throughout the day, reacting to what has been eaten and how much insulin has cleared out of the bloodstream, the hemoglobin A1C score moves much slower – it takes about 3 months to significantly shift the score through diet.

Full-blown type 2 diabetes is a hemoglobin A1C score of 6.5 or more. (Remember, type 2 diabetes is the type that is acquired in adulthood as a result of genetics, lifestyle, and diet.) By the time one reaches this high A1C score, many of the mechanisms that lead to diabetes are firmly established – especially if the body’s blood sugar regulation mechanisms have been challenged with a constant influx of sugar in the diet.

The effect of chronic hyperglycemia on various tissues of the body can be profound, leading to irreversible kidney damage, heart attacks, strokes, irreversible vision loss, chronic painful neuropathy, erectile dysfunction and cognitive decline.

What has been trained can be “untrained”

All is not lost, even if you’ve been diagnosed with diabetes. Preferably insulin resistance is discovered long before the onset of type 2 diabetes. This can be screened for using routine testing as part of annual exams, by performing a physical exam and checking blood tests such as fasting insulin levels, the HA1C test, and a fasting cholesterol panel. If you are diagnosed with insulin resistance, prediabetes, or type 2 diabetes, there are many strategies, such as the ones below, that can be implemented to reverse the progression of the condition, no matter how far the condition has progressed.

Strategies for retraining dysregulated blood sugar:

Many things address the underlying mechanism of low insulin sensitivity. Increasing insulin sensitivity can decrease the risk of insulin resistance and diabetes.

  • Walk fast. Walk slow. Repeat. Exercise directly reverses insulin resistance by causing cells to burn glucose for fuel and by increasing insulin sensitivity. Exercising makes the cells “hungry” for glucose again, so instead of resisting the action of insulin, they will accept glucose into their interiors again for fuel. In other words, frequent exercise can reverse insulin resistance. Fortunately, the exercise does not have to be high-intensity. Moderate exercise, such as walking for about 20 minutes a day, is enough to combat the mechanisms of diabetes (4). At a slightly longer duration in a different study, one hour of cycling 4 times a week for 6 weeks didn’t cause participants to lose weight, but it did increase glucose uptake by 30% (5).

  • Supersize your exercise. Exercise can be made more efficient by pulsing intensity levels. For walking, that could mean building up to 8 cycles of walking very fast for 30 seconds, then walking slower for 90 seconds. This is a modified version of “High-Intensity Interval Training” (HIIT). This pulsing of fast and slow walking allows you to get the metabolic impact of being on a treadmill for an hour, but it only takes 20 minutes. HIIT exercise, in general, has been deemed “a time-efficient strategy” for type 2 diabetes prevention compared with moderate-intensity exercise (6). The pulsing of fast and slow walking helps condition the heart, empty the bloodstream of glucose, and reverse insulin resistance. Resistance training to gain muscle mass can also positively impact insulin resistance (7) and is a great addition to an exercise program.

  • For pre-diabetics, intermittent fasting is another way to increase insulin sensitivity. Intermittent fasting is a way of eating that creates regular windows of fasting. Many people will eat all their calories in a 6 hour window. This allows a long time for the body to clear the bloodstream of glucose, give the pancreas a break, and allow the blood sugar system to reset. Note, this strategy may be dangerous for diabetics, especially those that are on certain diabetes medications. Please work with a healthcare practitioner on the ideal approach, considering your health history and current blood sugar status. A great resource on fasting strategies is a book called “The complete guide to fasting” by Dr. Jason Fung.

  • Eat a low-sugar/low-carb, whole-foods diet. Processed foods such as baked goods, pasta, and cereals easily cause high spikes in blood sugar. A Mediterranean diet, modified to reduce pasta and processed carbohydrates, can be a very healthy (and delicious) diet to help straighten out blood sugar issues. More aggressive carbohydrate restricted diets, like a ketogenic diet, may be necessary in some cases in order to achieve optimal results.

  • Pair carbohydrates with fats and proteins. Avoiding blood sugar spikes can be as simple as adding a pat of butter to a small serving of sweet potato or eating a boiled egg with some carrot and celery sticks. If a sugary dessert cannot be resisted, eating a small serving directly after dinner is helpful – you won’t eat as much because you’ll be full from dinner, but also the fats and proteins from the dinner can help slow the absorption of sugar into the bloodstream.

  • Eat at regular intervals. Training the body to understand it will get fed at regular intervals can help control blood sugar. Even if you are practicing intermittent fasting, eating at regular intervals during your eating window can reduce blood sugar spikes and prevent very low dips.

  • Weight Loss. Even losing 5 – 10% of your body weight can help restore normal blood sugar function and increase insulin sensitivity (8). For example, if you’re 200 lbs, losing as little as 10 lbs could help bring your blood sugar under control. If you’re walking regularly, this could happen rather easily.

  • Remember that epigenetics can change your destiny. Do not be dismayed if your family has struggled with obesity or diabetes. Research has shown that lifestyle factors such as diet and exercise can change the expression of genes, switching them on or off. The action of your genes can be modified, and the strategies listed above are all great ways to do that!

Things to consider:

Many things decrease insulin sensitivity, which ultimately can increase the risk of insulin resistance and diabetes. Most of these can be derived from the items above. However, here are some things that many people are not aware of:

Beware of hidden sugar. Many foods are traditionally considered “healthy” but can raise blood sugar to very high levels. A healthcare practitioner may ask you to avoid these foods for a few months while you get your blood sugar under control.

Address inflammation. Inflammation is suspected of being the root cause of numerous health problems. High blood sugar contributes to inflammation, so working on blood sugar should bring down unhealthy inflammation. However, dietary strategies and nutritional supplements can be added to your routine to lower inflammation.

Address stress. During periods of high stress, the hormone cortisol is released. Cortisol is sometimes called “the belly fat hormone” because it contributes to fat around the waist area. There are saliva tests for cortisol and numerous nutritional supplements that can help combat high cortisol. Exercise, deep breathing, and meditation (among many other strategies) can also help decrease cortisol and reverse hyperglycemia (9).

Rethink your alcohol intake. Most alcohol is not only calories devoid of nutrition, but it can also impact blood sugar levels!

Addictions may require counseling to overcome. Food, sugar, and alcohol addictions can be a fast road to ill health, including diabetes. It takes a willingness to address these issues, but for most people, there comes a day when you’ve just had enough of the negative consequences, and you’re ready to confront the addiction. We support that 100% and will refer you to trusted resources in the community.

Identifying and taking steps to improve blood sugar issues early on is extremely helpful in avoiding the serious health consequences that can come with type 2 diabetes. Managing your blood sugar is one of the best things you can do for your health, your energy, and your mental clarity. If you would like some help in understanding and managing your blood sugar, please contact us. We are privileged to help guide and support you in your health journey.


Jonathan Vellinga, M.D.

Jonathan Vellinga, MD is an Internal Medicine practitioner with a broad interest in medicine. He graduated Summa cum laude from Weber State University in Clinical Laboratory Sciences and completed his medical degree from the Medical College of Wisconsin.​

Upon graduation from medical school, he completed his Internal Medicine residency at the University of Michigan. Dr. Vellinga is board-certified with the American Board of Internal Medicine and a member of the Institute for Functional Medicine.




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  3. Insulin resistance: What it is, causes, symptoms & treatment [Internet]. Cleveland Clinic. [cited 2022Oct27]. Available from:

  4. Moderate exercise might be more effective at combating pre-diabetes [Internet]. Duke Health. [cited 2022Oct27]. Available from:

  5. Soman VR;Koivisto VA;Deibert D;Felig P;DeFronzo RA; Increased insulin sensitivity and insulin binding to monocytes after physical training [Internet]. The New England journal of medicine. U.S. National Library of Medicine; [cited 2022Oct27]. Available from:

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  7. 17 things that impact insulin sensitivity [Internet]. Diabetes Daily. 2017 [cited 2022Oct27]. Available from:

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  9. Holm G, Björntorp P. Metabolic effects of physical training. Acta Paediatr Scand Suppl. 1980;283:9-14. doi: 10.1111/j.1651-2227.1980.tb15300.x. PMID: 7010907.


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