Insulin Sensitivity: What Is it? And How Can You Improve It?
You’ve probably heard of insulin—it’s a hormone produced in the pancreas, and its chief responsibility is to regulate blood sugar (glucose). You may have heard that folks with diabetes don’t produce enough insulin or they’re insulin resistant, and insulin or other drugs that affect blood sugar levels are often prescribed to help regulate blood sugar levels. Yet, even if you aren’t diabetic, prediabetic, or insulin resistant—in fact, even if you’re metabolically healthy—insulin sensitivity is worth understanding and improving because poor insulin sensitivity can increase the chances of becoming obese as well as increase the risk for heart disease, diabetes, and a cascade of other “baggage” that tends to come with those health problems. Plus, increasing insulin sensitivity allows your body to better use carbohydrates for energy, and it makes it easier to manage your weight.
What is Insulin Sensitivity?
Most of us rely on glucose as a key source of energy for the body. Yet, many of our cells are unable to take up glucose without a bit of help. When we consume foods that are higher in carbohydrates (which are ultimately broken down into simple sugar), the pancreas releases insulin, which facilitates cellular uptake of blood sugar to provide the energy the cells need. When things are running smoothly, the insulin/glucose team work together to ensure blood sugar levels are stable and safe while providing the brain, heart, skeletal muscles, fat, liver, and other tissues of the body the energy they need.
Your insulin sensitivity is defined by how much insulin is needed to move a certain amount of glucose out of your bloodstream into your cells. Generally speaking, the less insulin you need to process a given amount of carbohydrates (i.e., blood sugar), the higher your insulin sensitivity. Those who are insulin resistant (impaired insulin sensitivity) need more insulin (sometimes a lot more) to process the same amount of glucose, and this is a major risk factor for developing type 2 diabetes.
And even though the pancreas may be working hard to produce enough insulin to get sugar out of the bloodstream, it becomes a battle to produce enough, and over time, the insulin-producing cells of the pancreas may become dysfunctional. That’s not good as long-lasting high blood sugar can then damage nerves and organs and lead to disease. Folks who have prediabetes or a family history of diabetes as well as those who are overweight or obese tend to have the greatest risk of impaired insulin sensitivity.
However, it’s completely possible for someone who’s “overweight” or “obese” (by Body Mass Index, BMI, standards) to be “metabolically healthy” and have normal insulin sensitivity. On the flip side, it’s completely possible for someone who’s “normal” weight to be insulin resistant.
10 Ways to Improve Insulin Sensitivity
While it’s not always easy to convince your significant other to be more sensitive, fortunately there are simple and effective lifestyle changes you can begin making immediately to help improve your insulin sensitivity. (Of course, we recommend you speak with your personal healthcare practitioner before making any diet, exercise, or supplementation changes if you have been diagnosed with any disease, including insulin resistance, pre-diabetes, or diabetes.)
1) Take a Walk. You likely thought this was going to be all about changing the diet. Don’t worry, we’ll discuss diet shortly. But one of the absolute best ways you can help your body become more efficient and effective at balancing blood sugar is by walking regularly. And it doesn’t have to take a lot of time either. One very recent study, for example, found that a short 10-minute walk after meals (especially after dinner) can be highly effective for controlling blood sugar.1 While regular walks have numerous benefits, the 10-minute after-meal walks were found to be even more effective than taking a 30-minute walk any time of day. Enjoy a nice stroll after lunch and dinner, especially if your meal was a bit heavier in carbs to improve your insulin sensitivity.
2) Exercise Consistently. A consistent exercise program is one of the best ways to improve insulin sensitivity. Incredibly, a single workout can increase your insulin sensitivity for at least 16 hours.2 And aerobic exercise, like jogging, cycling, or Zumba for 30 minutes or more has been shown to increase your sensitivity for up to 2-5 days, depending on the activity and duration (at least in healthy younger women).3
Resistance training—such as lifting weights— likewise helps improve insulin sensitivity, and more intense, multiple-set workouts tend to be the most effective.4 Your muscles need glycogen (the storage form of glucose in your muscles and liver) to fuel activity, and the more muscle you have, the more sugar your body can store (and burn). Think of it this way: Your muscles are like both the gas tank and the engine for the carbs you eat. The more muscle you have, the bigger your gas tank and the more energy you burn.5
One study found that resistance training over three months increased insulin sensitivity whether or not the subjects lost weight or saw other improvements in aerobic capacity. A program that combines both aerobic and resistance training like this balanced workout routine appears to work even better when it comes to boosting insulin sensitivity.6,7
3) Get Your ZZZs. Sleep is vital for health. It’s that simple. It’s critical for healthy, balanced hormone function—including insulin, ghrelin, leptin, growth hormone, sex hormones, cortisol, and more. If you want to impair your insulin sensitivity overnight, skip out on a good night’s sleep. Just one night of sleep deprivation (such as getting just four hours of sleep) can reduce your insulin sensitivity by 33% compared to getting a good 8 ½ hours.8 Fortunately, for those of us who do have an occasional night of not-so-good sleep, the disruption may be reversed by, you guessed it, getting enough sleep. One study found 9 days of recovery sleep helped normalize insulin sensitivity.9
4) Manage Stress. In today’s world, stress is just a part of life. Yet, not dealing with it in a healthy way and allowing it to become distress, or worse, burnout, can have a dramatic, negative effect on hormones, including insulin. When faced with acute stress, your body responds by releasing cortisol, which actually functions in the exact opposite way of insulin. For instance, cortisol helps mobilize sugar into the blood to fuel the body during a stressful situation. Unfortunately, if chronic stress is your usual mode of operation, the result of these signals is for cells to become less sensitive to insulin.10, 11 Taking the time for regular meditation, improving sleep hygiene, and getting outside are just three simple ways to help decrease stress levels.
5) Lose Weight. Insulin resistance is often paired with high levels of body fat, especially around the belly, and excess body fat is thought to be one of the contributors to insulin resistance. Losing a mere 5% of bodyweight, however, has been shown to significantly help improve metabolic health, including insulin sensitivity.12 To help put that in perspective, that would mean a 250-pound overweight man would need to lose just 12.5 pounds and a 180-pound overweight woman could lose just 9 pounds to begin experiencing profound health improvements, including reduced risks for diabetes and cardiovascular disease. It’s not enough to lose the weight though. You also want to maintain that weight loss by making healthy lifestyle changes. (Fortunately, by following the tips to help you improve insulin sensitivity, you’re also more likely to be able to keep that weight off for the long term.)
6) Eat More Fiber. Dietary fiber plays an important role in regulating blood sugar and insulin as it slows gastric emptying,13 helps with weight loss,14 and supports a healthy gut microbiota.15 Unfortunately, the average American consumes only half the recommended amount of dietary fiber. Consume more high-fiber vegetables, beans, oatmeal, chia and flaxseeds to reach the recommended 30 – 40 grams per day to enjoy the laundry list of health benefits fiber imparts, including improving insulin sensitivity.
7) Cut Back on Added Sugars. This one should be a no-brainer. If you cut back on the added sugars you consume (which are not the same as the sugars found in fruits and vegetables that are naturally packaged so neatly with fiber, antioxidants, etc.), you’ll naturally decrease the need for your body to produce copious amounts of insulin. Interestingly, it appears that the fructose (as found in the corn syrup that provides the sweetness in most packaged products) is a worse offender than glucose for decreasing insulin sensitivity.16 The simple solution: Cut back (or eliminate) processed junk food and drinks (which are the main sources of added sugars) and eat more whole, minimally processed foods.
8) Load Up on Vegetables. You likely already know that colorful vegetables and fruits in the diet provide serious health benefits. One reason is because they provide antioxidants such as polyphenols.17 A diet that’s rich in polyphenols and antioxidants like vitamin E (found in sunflower seeds, almonds, and wheat germ oil), alpha-lipoic acid (red meat, spinach, and broccoli), and N-acetylcysteine (a form of the amino acid cysteine that’s a precursor to glutathione) has been shown to have a “beneficial impact on insulin sensitivity.”18, 19
9) Spice Up Your Cooking. Various herbs and spices not only increase the flavor in foods without added calories or unhealthy additives, they can also provide copious health benefits. Fenugreek,20 turmeric,21 ginger,22 and garlic23 all appear to help improve insulin sensitivity or at least show promise, yet the most promising superstar appears to be cinnamon. One meta-analysis found that a mere ½ to 3 teaspoons of cinnamon reduced blood sugar levels when consumed daily.24, 25
10) Go Keto (or at least cut down on carbs). A very low carbohydrate diet (less than 30 to 50 grams per day) has been shown to reduce insulin levels. One small study with 10 obese diabetics who went on a ketogenic diet and decreased overall calories for just two short weeks found the subjects experienced a 75% increase in insulin sensitivity.26 Another study with 146 overweight individuals compared a low-fat diet with a ketogenic diet. In the 48-week study, insulin levels in the keto group dropped three times more than those in the low-fat group.27
The ketogenic diet isn’t for everyone, however, and it might not be right for you, so another way to improve insulin sensitivity is to eat smaller portions of carbs throughout the day rather than at one large meal.28 Look for lower glycemic index carbs as they have a slower release of sugar into the blood. Good choices include quinoa, sweet potatoes, brown rice, and old-fashioned oats.29
It’s also worth pointing out that while the ketogenic diet tends to improve measurements of insulin sensitivity (e.g., fasting insulin), this can be a bit misleading. You see, severe carbohydrate restriction leads to a heavy, primary reliance on fat/ketones for fuel, and this can actually result in what’s often referred to as “physiological” carbohydrate intolerance and insulin resistance. However, this does seem to be a temporary metabolic state (in healthy folks at least) that results from carbohydrate restriction and seems to normalize over time if/when returning to a normal, mixed diet.
How to Improve Insulin Sensitivity: A Recap
At the end of the day, improving your insulin sensitivity could help you lose weight and reduce your risk for heart disease, obesity, diabetes, and other metabolic diseases and may even help you live not only longer but better. By making the lifestyle adjustments above, you’ll be one step (if not miles) ahead.
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