What You Need to Know About Insulin Resistance—Even if You Don’t Have Diabetes
Insulin resistance. It’s something you may have heard about in relation to Type 2 Diabetes. But before you think, “I don’t have that—I can skip this info,” listen up: insulin resistance is a primary driver of weight gain, inflammation, cardiovascular disease and more. A large metric of health is your level of insulin sensitivity. Higher insulin sensitivity (the opposite of insulin resistance) equates to greater blood sugar regulation, weight maintenance/loss, better hormonal balance and decreased risk of heart disease, stroke, and diabetes.
It’s estimated that insulin resistance starts to increase several years before a person’s blood sugar levels start to increase and about five years prior to a person being flagged for type 2 diabetes. You don’t need to be drinking a 2-liter bottle of soda every day to develop insulin resistance. In fact, what I see most often in my practice are people consciously trying to make better food choices who are struggling with insulin resistance and may not even be aware. Common issues include not properly balancing their plates with enough protein and fat, they’re eating too many “healthy” high-glycemic foods in one sitting or they aren’t getting enough sleep at night.
So, here’s what everyone needs to know about insulin resistance, what causes it, and why it’s so important to keep in check.
Are you Insulin Resistant?
You might think that if you haven’t been diagnosed with Type 2 Diabetes (T2D), there’s no way you could be insulin resistant. However, nearly 1 in 2 adults in the United States has either T2D or pre-diabetes, which means almost half of the adult population has abnormal blood sugar levels. The saddest part about this shocking statistic is that insulin resistance—and the diseases it causes—is entirely preventable! In the last 50 years, our diabetes epidemic has been largely driven by increased access to highly processed refined carbohydrates and too many added sugars in our diet. Add to that our increasingly sedentary lifestyles, inordinate amounts of stress, and lack of sleep, and you’ve got a scenario in which we’re all teed up to have poor glycemic control.
Here’s one of my core beliefs, “Make time for optimal health now or pay later.” Insulin resistance is the perfect example of what paying later looks like. Because here’s the truth: You will not wake up one day and develop diabetes out of nowhere. The health of your insulin sensitivity exists on a continuum. Developing insulin resistance is a gradual progression that builds over the course of many years and many meals before it fully manifests and you’re diagnosed with pre-diabetes or T2D. And frankly, at that point blood vessel damage has been happening for years. Truly this is about even more than just prevention, it’s about finding the highest state of health and increasing insulin sensitivity can help you do that.
What Causes Insulin Resistance?
A primary driver of lower insulin sensitivity is regular fluctuations in blood sugar that are driven by chronic consumption of a high-glycemic diet loaded with added sugars, refined grains, liquid sugars (sugar in your coffee, fruit juice, sports drinks, etc) and too many whole grains. Eating this way is a primary trigger for a person to become less insulin sensitive—a.k.a. insulin resistant. Two additional contributors include excess fat accumulation around your waist; and high levels of inflammation.
Here’s how it works: Insulin is a hormone that’s produced by the pancreas and carries sugar from your bloodstream into your cells and muscle, where it’s either used for energy or stored for later. In a healthy system, your body makes just enough insulin to move the sugar (a.k.a. glucose) from your blood and into your muscle. Think of insulin as an uber driver and the glucose in your blood are a long line of individuals waiting to be picked up and the cell is the destination (in this case, there are three destinations: your muscle, liver and fat cells). If you flood your body with high levels of sugar and refined carbohydrates, it’s like creating a huge line of passengers who are waiting to be picked up. Your body identifies the demand and signals to your pancreas that you need more insulin (and requests more uber drivers) to meet the demand.
Imagine that the desired destination, your muscle, has a bouncer that typically welcomes all passengers and says, come in glucose! In the case of insulin resistance, the bouncer for your muscles (your insulin receptors and gluc-4-transporters) does not recognize the passengers and is not able to lock in the insulin. This often will lead to re-routing the insulin to your fat cells or to your liver. When re-routed to the liver, it can be stored as glycogen or converted to free fatty acids that are repackaged as triglycerides and increase risk of non-alcoholic fatty liver disease and hypertriglyceridemia (high triglycerides). Insulin resistance creates a build up of sugar in your bloodstream. When that happens, your pancreas gets the message that it needs to produce more insulin in an attempt to normalize blood sugar levels.
One of the most important takeaways about insulin is that in an ideal scenario, insulin does its job— delivering glucose to your cells and normalizing your blood sugar levels—and then it calms down. However, when you eat large amounts of sugar and you wear down your insulin receptor, insulin levels stay high. That’s when the problems start.
It’s not just pre-diabetes and T2D you have to worry about when your insulin is out of sync. Insulin resistance influences every organ in your body, including your mitochondrial function which can lead to lower energy production and exhaustion. Do you struggle with your weight? There’s a good chance insulin resistance is the cause. When your mitochondria detect high insulin levels, they shut off fatty acid oxidation and because insulin is a hormone that stimulates lipogenesis, it leads to fat storage. This is especially common around a person’s abdominal area, where you see an accumulation of visceral (or belly) fat.
The Health Food Trap
For about seven years, I was mostly a vegetarian (I ate some eggs and fish) because of the reported health benefits tied to improved heart health and longevity. What I did not realize is that my meals of oatmeal and strawberries or rice and beans was decreasing my insulin sensitivity. Many people that I work with fall into the same trap. They aren’t drinking soda or eating a lot of sugar, but their meals are largely whole grain carbohydrates with very little fat and protein.
I ended up doing a 10-day elimination diet of gluten, dairy, grains, starchy vegetables, beans and sugar. In other words, I ate only low-glycemic foods for those 10 days—and I was starving and tired because I was not metabolically flexible. After I had several lab panels done and I learned that not only did I have several key amino acids deficiencies, but my insulin levels were not optimal.
I share this story because there’s a good chance many of you are eating healthy foods but you still may be having too many moderate glycemic carbohydrates (and not enough protein and fat), too many “healthy” sugars like coconut sugar and maple syrup, or eating too frequently and all three of these things can interfere with your insulin. For example, a bowl of oatmeal with 1 cup strawberries and almond milk or a serving of quinoa with black beans and squash will provide a high glycemic effect and it contains too little protein to help offset the insulin response. Eating this way over time can lead to weight gain, decreased insulin sensitivity, pre-diabetes, and eventually even T2D. Insulin resistance also occurs in approximately 50% of women with polycystic ovarian syndrome (PCOS).
So, What’s the Best Way to Prevent or Treat Insulin Resistance?
It’s worth noting that each person’s blood sugar response and insulin sensitivity is unique and is largely influenced by our gut microbiome. Your microbiome composition will determine how you handle the glycemic level of certain foods. But there are several general tips that you can adopt to your own unique needs. Here are my science-backed ways to prevent (or reverse!) insulin resistance and support insulin sensitivity (and your metabolism, heart health, brain health, hormonal health and all areas of the body influenced by your insulin levels):
Follow my Optimal Plate Method
That means filling half of your plate with non-starchy veggies, incorporating protein and healthy fat with every meal. For many, it will mean limiting complex or starchy carbohydrates to one serving per meal or less. For those with high insulin levels, consider limiting the complex or starchy carbohydrates to no more than one serving per day. You also want to avoid refined flours and carbohydrates altogether.
Limit Complex or Starchy Carbohydrates
This includes whole grains, starchy vegetables (potatoes, sweet potatoes, butternut squash, acorn squash, plantains), and fruits. Consider removing grains from your diet, as both refined and whole grains can increase some people’s blood sugar levels more rapidly. For fruits, prioritize low glycemic options like grapefruit, berries, lemons, limes, and cherries.
Reduce Added Sugar Intake
Do a pantry assessment to become aware of all of the hidden sources of sugar that are sneaking into your diet. Use my Free Beingbrigid Blueprint to learn more about where sugar may be hiding in your foods.
Avoid Drinking Liquid Sugar
Almost half of the added sugar in the United States food supply comes from beverages like coffee with sugar — such as vanilla lattes and mochas, fruit drinks, soda, sports drinks and other sweetened beverages. Liquid sugar is absorbed in the body more rapidly than added sugar found in foods. One of my favorite unsweetened alternatives is Drink Sound, sparkling teas. If you are interested in trying them, use my discount code: BRIGID20 for 20% off your purchase. I do not receive money on this affiliate code but love them that much!
Include 2 Tbsp Ground Flaxseeds Every Day
Flaxseed supplementation in the diet has been shown to lower insulin resistance. Add 2 tbsp ground flaxseeds to a smoothie, chia pudding, salad, vegetable dish or yogurt bowl daily!
Avoid Grazing Throughout the Day
Everytime that you eat, your insulin levels go up. Be sure to eat once every few hours and allow for breaks in between to give your pancreas a break from producing so much insulin.
Fast for 12-16 Hours Overnight
Practicing time restricted eating for at least 12 hours overnight promotes DNA repair and can improve insulin sensitivity. The key is figuring out the best fasting window that works for you. Learn more about time restricted eating here.
Aim for At Least 40 grams of Fiber
Work your way up to increasing fiber in your diet through whole foods sources. This includes nuts, seeds, non-starchy vegetables, low glycemic fruits and legumes. If this creates digestive issues, then you’ll need to start with fixing your gut health.
Add 1-2 Tbsp Organic, Raw Apple Cider Vinegar
Incorporate 1-2 Tbsp of apple cider vinegar in 6-8 fl oz of filtered water 1-2 times per day. The acetic acid in apple cider vinegar and all vinegars helps to increase the muscle’s uptake of glucose. Find out more about the science behind why this works so well here.
Prioritize Moving your Body Daily
Movement is essential for increasing your cell sensitivity to insulin. Your movement needs will be very individualized but the general recommendations include: cardiovascular exercise for 30-45 minutes (5 days per week) and strength training for 10-30 minutes (3 days per week).
Focus on High Quality Sleep
Research shows that when you sleep, you repair your cells, regulate your satiety hormones and improve your insulin sensitivity. Prioritize high quality sleep and 7-9 hours per night.
Prioritize Stress Reduction
Over time, chronic stress can keep blood sugar levels elevated. As a result, fat cells become less sensitive to insulin. This increases the body’s inclination to store fat and contributes to insulin resistance.
Incorporate Adequate Intake of Magnesium
Magnesium is critical for insulin signaling. Magnesium can be found in foods such as avocado, black beans, spinach, pumpkin seeds, almonds and dark chocolate (>70%). Some people may require additional magnesium through supplemental form to achieve adequate levels.
Bump Up the Vitamin D
Vitamin D has been shown to play a role in the regulation of insulin sensitivity. If possible, try to get 15 minutes of natural sunlight exposure and increase vitamin D rich foods in your diet. These foods include wild sockeye salmon, canned sardines, oysters, egg yolk and some fortified milk products. Consider taking a vitamin D supplement to ensure that you have optimal levels of vitamin D. Prior to taking any supplements, always discuss with your doctor and/or registered dietitian.
Getting Tested for Insulin Resistance
There are several tests that can be conducted to understand where you fall on the insulin sensitivity spectrum. These are labs that we look at in my VIP Next Level Nutrition program. You may want to see if your doctor is checking these levels and if not, have a discussion about it with them to see if they think it would be beneficial to order.
The key test to determine your level of insulin resistance is fasting insulin. This is not always tested in conventional medicine. Discuss this with your doctor and see if he/she believes that it could be a useful screening tool. In functional medicine, an ideal fasting insulin level is considered to be <8 ?IU/dl.
If your doctor does not check your insulin levels, calculate your triglyceride/HDL ratio. Look at your most recent lab work that your doctor ordered and take your triglyceride level and divide it by your HDL cholesterol level. A ratio>/= to 3.0 may be suggestive of insulin resistance.
Hemoglobin A1c (HgA1c)
Your HgA1c level indicates your average blood sugar levels over the past three months. This is a blood draw that is sometimes included in an annual physical. It is a test that is used to monitor individuals with diabetes. If your doctor does not check this level then you may want to have a discussion about checking it. An optimal range for someone that does not have any signs of diabetes is between 4.6 to 5.3 percent.
Fasting Blood Glucose
Fasting glucose looks at the level of glucose that is found in the blood after a period of fasting for approximately 12 hours. This is a common blood draw that doctors commonly test for in an annual physical. A desirable fasting glucose level is between 70-90mg/dL.
Testing your daily cortisol curve (4-6 collections throughout the day) can be so beneficial for understanding your current stress response. Elevations in cortisol from drinking something like a cup of black coffee (with no calories or carbohydrates) can increase your morning cortisol levels and thus, your blood sugar levels and production of insulin. Understanding the role that stress plays can be a real game changer. This is a saliva test that I run in our My Food is Health program.
Additional test results that may be elevated when a person has insulin resistance are ferritin, fibrinogen, uric acid, and liver function tests (AST, ALT, GGT).
You may also consider getting additional information from an at home glucose monitor that allows you to see your fasting blood sugar levels each morning and your blood sugar levels within one and two hours after your meals. There is some evidence that suggests your blood sugar response within 1 hour and 2 hours of eating is the most helpful for understanding your glucose regulation and insulin sensitivity.
Being aware of insulin resistance and how you can improve your insulin sensitivity is essential for everyone but sadly the conventional medicine model does not have a proactive framework for assessing insulin resistance early. There is much more focus on treating full blown type 2 diabetes on the backend. But here’s the truth: you are in control and you are not your genes or your previous choices. You can start making time for optimal health now and become your own health advocate.