What is Insulin Resistance?

Why This is Important

Understanding the mechanism and causes of insulin resistance is essential to the lifestyle management and reversal of diabetes. Not just because it is the root cause of pre-diabetes and Type 2 diabetes, not just because failure to address insulin resistance can lead to increased risks of Alzheimer’s and heart disease,  but because it will enable you to make the choices that lead to disease reversal and add quality years to your life. 

Insulin resistance can also be a factor in Type 1 diabetes and some of the other less-well-known types of diabetes. It is also present in metabolic syndrome. So understanding this process is important -- whether you are trying to prevent diabetes or whether you are trying to reverse diabetes. You see,  optimal health is the result of addressing the root causes of disease, not just the signs and symptoms. Elevated blood sugar is just a symptom of a deeper problem.

What is it?

So what does insulin resistance look like? It is an abnormal metabolic disorder in which the cells of the body fail to respond normally to the hormone insulin. Insulin is produced in the beta cells of the pancreas and one of its primary jobs is to unlock the door into the cell through which glucose (a simple sugar that comes from the food you eat) can get in and become the fuel that produces the energy that keeps you alive. Whenever you eat carbohydrates, your pancreas releases insulin which works like an escort to get glucose from the blood into the cell and thus lowers the amount of glucose circulating in the blood. In insulin resistance, it’s like the locks on the doors into the cell are sticky. The insulin shows up, but sometimes the door doesn’t open. The result is increased levels of circulating glucose. The cell needs the glucose but the glucose can’t get in as it should, leaving the cell in a state of relative starvation.

The most insulin-sensitive tissues in the body, which normally burn the greatest amounts of glucose for fuel, are your skeletal muscles. The liver helps to control levels of glucose in the blood by not putting glucose out when it senses the presence of insulin. In insulin resistance, this liver mechanism is impaired as well.

How does it affect your body?

When insulin resistance is present, the pancreas puts out extra high levels of insulin trying to force more sugar into the cells. Because high insulin levels also signal the body that there is too much energy, in the form of glucose, available, it pushes the storage of this extra fuel into fat cells, which promotes weight gain. 

So what you see is glucose going into the blood from normal meals that starts getting stored as excess fat instead of getting burned for fuel. This insulin-stimulated fat accumulation characteristically is stored around the vital organs in the abdomen, increasing waist circumference in both men and women. This type of fat storage is associated with an increased risk of a variety of chronic lifestyle diseases such as diabetes, high blood pressure, heart disease and obviously, obesity. 

The increase in fat stores around your vital organs is called visceral adiposity. The fat stored here works differently than the fat stored under your skin in other parts of your body. This visceral fat is very inflammatory and leads to the production of cytokines that increase inflammation in the body generally and and disrupts normal insulin action even more, leading to whole-body insulin resistance. 

The Link to Alzheimer's Disease

This insulin resistance in the brain tissue is now being understood as an underlying factor for the development of many of the cognitive deficits seen in Alzheimer’s disease. In fact, some scientists are now referring to Alzheimer’s as “Type 3 diabetes”. This term is not officially a diagnosis yet, but points to the fact that the two diseases are closely linked.

The good news here is that when you address insulin resistance for the improvement or reversal of diabetes, you also help your brain and decrease your risk for developing Alzheimer’s.

Link to Diabetes Development

As insulin levels increase, at first the larger quantity compensates for its decreased efficiency, and blood glucose levels may stay normal. But as resistance increases OR the beta cells in the pancreas become fatigued from overwork, fasting blood sugars and/or after meal blood sugar levels start to rise. When insulin can no longer compensate for the poor carbohydrate metabolism, you move into pre-diabetes and then Type 2 diabetes.

How to Increase Insulin Sensitivity

Understanding these factors then, underline the importance of not just normalizing your blood sugars and A1c levels, but addressing the insulin resistance by increasing insulin sensitivity. One of the most effective ways to increase your tissue sensitivity to insulin is to decrease the amount of fat stored in muscle tissue through regular aerobic exercise. High-intensity intermittent exercise has been shown to be extremely effective at reversing insulin resistance.

The second most effective approach to increasing sensitivity to insulin is to decrease body fat stores in general. This can be done by losing weight and implementing a low-fat diet. This last recommendation highlights the weakness of some of the most popular approaches to lowering blood sugar - specifically using a low-carbohydrate and high-fat diet. Although this can lower blood sugars related to meal consumption and over time also helps many people to lose weight, it actually INCREASES insulin resistance so that your risk of heart disease and other diabetic complications are not lowered. So although losing weight can be helpful, HOW you lose weight also matters. Losing weight using a plant-based, whole-food diet approach gives you the best of both worlds. You experience increased insulin sensitivity, and for many people, it also promotes weight loss. Everyone will decrease their risk of experiencing progression of diabetes and its many complications as their insulin sensitivity improves.

Using Your Superpower -- Personal Choice

So what are you going to do today to improve your insulin sensitivity? How about getting outside for some sunshine and exercise? Your body will thank you.

References

https://en.wikipedia.org/wiki/Insulin_resistance

de la Monte SM. Insulin resistance and Alzheimer's disease. BMB Rep. 2009;42(8):475-481. doi:10.5483/bmbrep.2009.42.8.475 (available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4600067/)

Neal D. Barnard, Joshua Cohen, David J.A. Jenkins, Gabrielle Turner-McGrievy, Lise Gloede, Brent Jaster, Kim Seidl, Amber A. Green, Stanley Talpers. A Low-Fat Vegan Diet Improves Glycemic Control and Cardiovascular Risk Factors in a Randomized Clinical Trial in Individuals With Type 2 Diabetes. Diabetes Care Aug 2006, 29 (8) 1777-1783; DOI: 10.2337/dc06-0606.  (available here: https://care.diabetesjournals.org/content/29/8/1777)