Insulin Resistance: What It Is and How to Treat and Prevent It
Diabetes is one of the most widespread and damaging diseases in the Westernized world. The CDC estimates that 9.4% of the US population has diabetes with another 33.9% being prediabetic. Diabetes significantly increases risk for heart disease, our number one killer. It is also a leading cause of limb amputations, blindness, and the need to go on kidney dialysis. The majority of people with diabetes have type 2 diabetes, which means it is lifestyle-related and can thus be treated with meaningful lifestyle changes. (1) Furthermore, the deterioration in effective insulin use by the cell, called insulin resistance, starts years before a type 2 diabetes diagnosis providing ample opportunity for intervention (2). And insulin resistance itself has been linked to other adverse health outcomes, such as fatty liver disease and polycystic ovarian syndrome (PCOS). This handout will discuss insulin resistance, how it can progress to diabetes, and what you can do to treat these issues using lifestyle changes.
In understanding insulin resistance it is first important to understand insulin/glucose physiology. A useful analogy is to think of insulin as the key that unlocks the cell allowing glucose to enter, where it can then be used for energy. Insulin resistance is a term used to describe a pathological state in which the cell does not allow glucose in despite the presence of insulin. It's like the call becomes “numb” to insulin.
So what causes insulin resistance? The answer is multifactorial but one major cause is fat. This includes the fat we wear and the fat we eat. A primary cause for many people is their dietary intake of saturated fat. The exact mechanism by which insulin allows glucose to enter the cell is somewhat complex, involving a cascade of chemical signals within the cell. Consumption of saturated fat mucks with this process by building up in muscle cells (called intramyocellular lipid) and then releasing toxic breakdown products which block the signaling pathway that normally allows glucose to enter the cell. In the end, the cell does not get the message to allow glucose in. (2)
Being overweight or obese is a major risk factor for insulin resistance and diabetes. Again, the reasons are complex, but we know that people who carry extra fat tend to deposit fat on their organs, including the liver, causing dysfunction in blood sugar metabolism. In addition, the cells of obese people have been found to be in a state of stress due to overnutrition, which causes them to dampen down their sensitivity to insulin. Finally, overweight and obese people tend to have an increased level of inflammation which also contributes to insulin resistance. (3) The important take away is that weight loss in overweight pre-diabetics and diabetics is critical to treatment.
The role of fat in insulin resistance and diabetes may be surprising as we have been told over and over that carbohydrates cause diabetes. However, the spike that diabetics see in their blood glucose readings after eating a carbohydrate-containing food is a symptom of insulin resistance, NOT the cause. Avoiding carbohydrates to keep blood sugar low while not addressing the actual causes of this carbohydrate intolerance is short-sighted and does not treat the underlying insulin resistance that causes diabetes.
It is worth noting that refined sugars, such as high-fructose corn syrup, do contribute to insulin resistance. Refined sugars are very calorie-rich and thus contribute to weight gain and obesity. In addition, refined sugars are rapidly metabolized into fat, which can then be deposited onto the liver leading to a condition called fatty liver. Fat build-up in the liver disables normal insulin signaling much like it does in muscle cells, resulting in chronically elevated blood sugars. (4) It is therefore in your best interest to avoid sweetened beverages and other refined sugars.
Your insulin sensitivity is largely under your control, even if diabetes runs in your family. That means that even if you are already diabetic, you can treat the condition through lifestyle modification, the most impactful being dietary changes. It is important to decrease your saturated fat intake as much as possible. This means minimizing animal products (red meat, poultry, fish, eggs, dairy) as well as oils (such as olive, canola, and coconut oils). In addition, you should strive to avoid refined sugars such as soda, cakes, cookies, and candy since they contribute to fatty liver, dysfunctional blood sugar metabolism, and are high in calories while being low in nutrients.
Research has consistently shown a plant-based diet to be protective against diabetes (5). That means eating a variety of whole grains, vegetables, tubers, fruits, beans, and nuts/seeds. Whole grains include foods like brown rice, steel cut oatmeal, and whole wheat. Tubers include starchy foods like potatoes and carrots. Despite what you may have been told about starch, such foods (in their unprocessed form) are absolutely a healthy part of an overall plant-based diet. Remember that having high blood sugar after eating healthy, carbohydrate-rich foods like potatoes is only a symptom of insulin resistance, not a cause. Many diabetics are also afraid to eat fruit because it contains sugar. Rest assured that sugar eaten in the form of whole fruit is metabolized much differently than processed sugar and has never been shown to promote diabetes. In fact, the opposite is true, so eat as much fruit as you want.
Regular exercise helps to keep your muscle cells insulin sensitive and thus maintain normal blood sugars. It also promotes a healthy weight. Therefore, it is critical to addressing insulin resistance and diabetes. (6) Shoot for an average of 150 minutes of moderate- to high-intensity exercise per week. However, even if you can’t hit this goal, every little bit of exercise you can do has beneficial effects.
The good news is that insulin resistance is completely preventable and even reversible the majority of the time. The most important lifestyle recommendations to keep yourself insulin sensitive are summarized below:
1. Avoid saturated fats. This is not a popular suggestion as many people's favorite foods are rich in saturated fat. Fortunately following this advice is easy to do when following a whole foods, plant-based diet. When it comes to fats, opt for the whole plant versions like nuts and seeds. And no, oils are not healthy. They are a processed food and the most calorically dense food on the planet, so skip them, too.
2. Avoid refined sugars, especially soda and other sugar-sweetened beverages. As stated previously, these wreak havoc on your liver. They are also calorie rich while being nutrient poor. But don't make the mistake of avoiding all carbohydrates. Complex carbohydrates found in whole foods like brown rice and steel cut oatmeal are health-promoting. Also don't be afraid to eat whole fruit. Many people mistakenly believe that because fruit contains “sugar” it should be limited. In actuality, multiple studies have shown that fruit is protective against conditions like diabetes and obesity.
3. Stay active. Exercise readily increases the insulin sensitivity of your muscle cells. Try to do something active most days, preferably for 30-60 minutes. Break it up into smaller chunks if you need to.
If you would like more guidance in addressing your insulin resistance or diabetes, feel free to schedule a consultation, or sign-up for our Diabetes Reversal Immersion.