How to treat insulin resistance

Insulin resistance is a common, almost silent condition in which the body’s tissues stop responding effectively to the hormone insulin.1 This causes the pancreas to secrete even more insulin to keep blood sugar stable.

As described in our in-depth companion guide: What you need to know about insulin resistance, this becomes a vicious cycle with insulin rising higher and higher and cells becoming even more resistant.

Eventually this may lead to pre-diabetes, type 2 diabetes, or other chronic health conditions.

For more information about how and why insulin resistance happens, the health conditions related to insulin resistance, and how insulin resistance is diagnosed please refer to our companion guide.

Doctor consulting with patient presenting results on digital tablet tablet  sitting at table

What you need to know about insulin resistance

GuideInsulin is an essential hormone we can’t live without. What happens, however, when it is chronically too high? Our tissues stop responding to it effectively. That’s insulin resistance.

In this guide we describe what you can do to treat insulin resistance, especially with powerful lifestyle actions.


Can drugs help?

If you have been diagnosed with insulin resistance, your first question may be whether any medications can treat this condition. The answer, unfortunately, is no. The FDA has not yet approved a single drug to treat insulin resistance.

Many doctors will prescribe the popular diabetes drug metformin, also known by the trade name Glucophage, for patients with insulin resistance. It works by decreasing glucose production by the liver and increasing the insulin sensitivity of cells.2 While metformin can lower blood glucose, it does not address the underlying causes.

If drugs cannot address the underlying causes of insulin resistance, what can? This guide explores the lifestyle answers through the latest research evidence.


The low-carb, ketogenic diet

Practically any dietary intervention that results in weight loss, especially fat loss around the abdomen, can temporarily improve insulin sensitivity.3 But if you want to make the largest impact, the low-carb, ketogenic diet may be better than the others.4

The reason is simple: if you are not eating sugar, or carbohydrates that rapidly digest to sugar, you will have less sugar entering your blood stream and therefore less need for higher levels of insulin to move sugar (glucose) out of the blood and into cells.

Recent studies show that a low-carb ketogenic diet can be an effective diet for reversing type 2 diabetes.5 Since insulin resistance is the underlying issue behind type 2 diabetes, a low-carb diet is also likely a good diet for reversing the pre-existing insulin resistance before full-blown type 2 diabetes develops.

One study in 2005 showed a 75% reduction in insulin levels in ten obese patients with type 2 diabetes who went on a low-carb diet.6

In two other studies, a very-low-carbohydrate diet was better at lowering insulin levels than a low-fat diet.7 Of note, both groups had equal weight loss in these studies, showing that it was the composition of the diet, not the weight loss alone, that was the most effective intervention to bring insulin levels down.

Yet another trial showed that a low-carb diet was better than a low-fat diet plus a popular prescription weight loss drug for lowering insulin, glucose and HbA1c levels.8 Again, both groups lost the same amount of weight, but the diet with the lower carbohydrate levels achieved better results in blood sugar control and insulin levels.

Takeaway: In order to reduce insulin resistance, you may need to reduce your intake of sugar and carbs that digest to sugar. That dietary change will result in reduced insulin production.

What does this diet look like? Dozens of guides on our site delve into all aspects of low-carb and ketogenic eating. Check out these two to start:


Other dietary evidence

It is important to note that studies also show that any diet that causes weight loss can reduce insulin resistance and improve insulin sensitivity — at least for a time.9

The reverse is true, too. Any diet that causes a rapid increase in bodyweight, such as from consuming high-carb, high-fat, high calorie foods (sometimes called over-nutrition), can immediately cause insulin resistance — within days — even among healthy young men.10

Over the years, three other areas of research have explored the possibility of specific diets decreasing insulin resistance:

  • increasing dietary fiber intake
  • eating low-glycemic-index foods
  • lowering dietary fat intake

None of the research to date, however, has compared these dietary approaches to eating a low-carb, ketogenic diet.

To learn more about the strengths and weakness of these other dietary approaches, and why we recommend low-carb eating, click below:

Dietary fiber

Should you eat more fiber to improve insulin sensitivity? The answer is likely yes, at least compared to eating a diet high in refined carbohydrates and low in fiber.

The fiber in your diet comes from carbohydrate-based plant foods the body cannot digest. There are two types of fiber: soluble fiber, which dissolves and absorbs water, and insoluble fiber, which does not absorb water and passes through the digestive tract largely unchanged. Soluble fiber is found in many edible plants such as peas, beans, leafy green vegetables, oats, and fruit. Insoluble fiber is largely from the bran (the outside shell) of whole grains.

Studies have shown that diets high in both types of fiber reduce insulin resistance when compared to diets high in refined carbohydrates and low in fiber (Diabetes Care 2006: Cereal fiber improves whole-body insulin sensitivity in overweight and obese women [randomized trial; moderate evidence]).

Low-carb ketogenic diets, which include plenty of above-ground vegetables, are often high in soluble fiber. We are not aware of any studies that have been done comparing a low-carb, high-fiber diet to a high-carb, high fiber-diet to see which is more effective for reducing insulin resistance, but the best bet to improve insulin sensitivity is likely to eat low-carb, high-soluble fiber foods.

Low glycemic index carbohydrates

Foods that have exactly the same carbohydrate content can differ in terms of blood sugar response, or how much blood sugar goes up after consuming the food. This is called the food’s “glycemic index” (GI).

While one might assume lower-GI foods that cause less blood sugar impact would naturally promote improved insulin sensitivity, study results have been mixed.

One 2014 randomized control trial found no difference between high and low GI foods (while keeping carb levels constant) on insulin sensitivity (Journal of the American Medical Association 2015: Effects of high vs low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity [randomized cross over; moderate evidence]).

A 2018 systematic review and meta-analysis found low GI carbs did improve blood sugar levels on a number of measures, but the analysis did not examine the impact on insulin levels or insulin sensitivity (Nutrients 2018: The effect of dietary glycaemic index on glycaemia in patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials [strong evidence]).

As the scientific debate continues, low-carb, low-GI foods are likely the best bet for addressing insulin resistance.

Dietary fat

Some researchers cite high dietary fat consumption as a primary cause of insulin resistance (Clinical Nutrition 2004: Dietary fat, insulin sensitivity and the metabolic syndrome [review article; ungraded]). Fat on its own, however, causes very little insulin to be released; only the consumption of carbohydrates and proteins cause an insulin pulse from the pancreas.

Many of the studies claiming dietary fat is the culprit were done in mouse and rat models where the rodents were over-fed a high-fat “chow.” (American Journal of Physiology, Endocrinology and Medicine 2010: A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain [mouse study; very weak evidence]).

The animals in these studies ate a surplus of calories in addition to fat, and the fat was usually low-quality industrial vegetable oils rich in omega-6 fats. It is impossible to know if the hyperinsulinemia results from the excess calories, the carb content of the chow in combination with the fat, the pro-inflammatory nature of the synthetic chow, or simply from the fat itself.

Human studies suggesting fat, specifically saturated fat, worsens insulin resistance are frequently confounded by including a combined high-carbohydrate and high-fat diet. For instance, one study from Diabetes Care used a diet comprised of 57% carbohydrate and 28% fat, and another study comprised 45% of calories from carbohydrates (Diabetes Care 2002: Effects of diets enriched in saturated (palmitic), monounsaturated (oleic), or trans (elaidic) fatty acids on insulin sensitivity and substrate oxidation in healthy adults [randomized controlled trial; moderate evidence]; Diabetologia 2001: Substituting dietary saturated fat for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWI study [randomized controlled trial; moderate evidence]). In addition, we need to balance these findings with studies that show no increased risk for insulin resistance with saturated fat intake (American Journal of Clinical Nutrition 2010: Effect of changing the amount and type of fat and carbohydrate on insulin sensitivity and cardiovascular risk: the RISCK (Reading, Imperial, Surrey, Cambridge, and Kings) trial [randomized controlled trial; moderate evidence]; Journal of Nutrition 2014: Diets high in protein or saturated fat do not affect insulin sensitivity or plasma concentrations of lipids and lipoproteins in overweight and obese adults [randomized controlled trial; moderate evidence]). In short, the evidence is not confirmed that saturated fat worsens insulin sensitivity, especially in the setting of a low carb diet.

Some hypothesize that inflammation may be the underlying mechanism linking fat to insulin resistance, thus it is no surprise that high-fat intake in the presence of high-carbohydrate, pro-inflammatory foods could make insulin resistance worse (Lipids in Health and Disease 2015: The role of fatty acids in insulin resistance [overview article; ungraded]).

In fact, one study showed that replacing carbohydrates with monounsaturated fat improved insulin sensitivity, which suggests fat is actually not the problem; the key instead is to lower carbohydrates (Diabetes Care 2013: The effects of carbohydrate, unsaturated fat, and protein intake on measures of insulin sensitivity [randomized-controlled trial; moderate evidence]). Again, fat is the only macronutrient with no significant effect on insulin levels.

We are not aware of any high-quality human studies that adequately control for the amount and type of calories, the amount and type of carbohydrates, and the amount and type of fat in a way that would allow the study authors to assess whether fat consumption causes (or improves) insulin resistance or hyperinsulinemia.

In fact, dietary fats are not likely the key issue at all. It is likely highly-processed foods which are high in both carbs and fat that contribute to insulin resistance.

 
Takeaway: A diet that is low in carbs, higher in fat and high in soluble fiber from above-ground vegetables appears to have the best current evidence for reducing insulin resistance.


Intermittent fasting/time-restricted eating

Intermittent fasting is a new dietary trend that entails exactly what it sounds like: not eating during certain time periods. Though it may seem like a fad, recent research is promising.

Studies suggest intermittent fasting can improve insulin sensitivity.11 If you are not eating, especially if you are not eating carbs, blood sugar is not entering the blood stream at the same rate and insulin is not released to compensate. This should allow the cells the opportunity to recover and become more insulin sensitive. Much like low-carb eating, fasting gives your pancreas a break.

Although fasting and time-restricted eating are related, they do have slightly different meanings. Time restricted eating is a type of intermittent fasting that involves eating meals in a set time-frame each day, such as only between 11 am and 7 pm. A review of studies in healthy subjects showed that fewer meals during a shorter feeding window caused better glucose and insulin levels.12

Healthy males who fasted for 20 hours every other day for 15 days showed greater glucose uptake with the same insulin levels, in essence improving their insulin sensitivity.13 Another trial showed better improvements in insulin resistance among women using intermittent caloric restriction (fasting) compared to chronic caloric restriction.14

Based on this data, the combination of a low-carb, high-fat diet with periodic intermittent fasting is likely the most effective nutritional intervention for treating insulin resistance and hyperinsulinemia.

Intermittent fasting may seem daunting, but if you are interested in exploring it, check out our guides:


Physical activity and exercise

Muscles burn glucose for energy. The more you move, the more glucose your muscles take out of the blood for energy use, which helps to lower your blood sugar levels. This allows for a reduction in insulin secretion, lessening the burden on your pancreas.

Likewise, muscles that don’t move don’t use up blood sugar, so insulin levels can rise to process any excess. Studies show that a mere five days of bed rest induces a state of insulin resistance in completely healthy volunteers.15 Multiple studies show that long-term inactivity is strongly associated with insulin resistance, metabolic syndrome and pre-diabetes.16

Any type of regular movement can help. Studies suggest that high-intensity interval training (HIIT), resistance training, and cardio training all improve glucose utilization and thereby improve insulin sensitivity.17

No matter what your preferred form of movement or exercise, it is clear: inactivity can lead to insulin resistance. And movement increases insulin sensitivity as long as the exercise continues.18 So if you stop moving regularly, insulin resistance may come back. (Move it or lose it!)

One more thing on exercise: you likely cannot outrun a bad diet. Exercising regularly but still eating a high-carbohydrate, high-sugar diet will likely counteract most of the benefits derived from exercise.

Therefore, exercise is best used in combination with a low-carb or ketogenic nutritional approach for treating insulin resistance and hyperinsulinemia.


Sleep

Studies show that short-term sleep deprivation raises glucose levels and worsens insulin resistance.19 A chronic sleep disturbance, such as from obstructive sleep apnea, is also associated with worsening insulin resistance.20

It’s unclear how much sleep is too little, just enough, or too much. Is there a difference in insulin sensitivity in someone who gets six hours of sleep per night instead of eight? Is there a certain amount of lost sleep, or a frequency of number of bad nights that triggers insulin resistance? We don’t know.

However, it is clear that there is an association between insulin resistance and sleep. And treating sleep problems may result in improved insulin sensitivity.21


Stress

Studies show temporary insulin resistance arises during periods of short term physiological and psychological stress, such as a sudden illness or sudden threat.22 This was likely an evolutionary advantage at some point in human existence: having higher insulin levels likely helped us heal faster (or deal with that sabre-tooth tiger). This insulin resistance reverses when the sudden stress is over. Such a response to a short-term stress likely has no long-term negative consequences.

However, it also appears that chronic stress and chronic activation of the body’s fight or flight response will also lead to insulin resistance.23 Since this chronic stress is longer-term, without a sudden onset and quick resolution of the trigger, it may lead to longer-term negative consequences.

Studies showing that stress reduction techniques can improve insulin sensitivity are not available. However, it is likely that mindfulness training, yoga, meditation, and even dancing, singing and other methods of relaxation like walking in nature can be effective ways to reduce stress, improve a sense of wellbeing and improve overall physical health.

Explore the ways that you relax best and you may be helping improve your insulin sensitivity.


Tobacco use

No aspect of smoking is good for health, but some studies report that active smoking is associated with insulin resistance and the development of diabetes.24 Although it is difficult to control for other potentially unhealthy activities in which many smokers may also engage, an increased risk does appear to exist.25

It is clear that quitting smoking is critical for improving health on many different levels, and your insulin sensitivity is no exception.


Can we cure insulin resistance?

Once someone has dramatically improved their insulin resistance and brought their insulin levels and their blood sugar down by eating a low-carb diet, improving their exercise, stress management and sleep performance, the question then becomes: are they cured?

Probably not. The word cure implies that the person can go back to eating however they want and the insulin resistance will not return. Unfortunately, that’s not how it works. The vast majority of people who reverse their insulin resistance, lower their chronically high insulin levels, and lower their blood sugars will see those all return to previous high levels if they stop their lifestyle interventions and return to their old diets and habits.

This reinforces the need to make lifestyle changes that can be maintained for decades and lifetimes. Crash diets or short-term interventions only help in the moment. Insulin sensitivity is a lifelong balance.

However, some people may have what amounts to a partial cure, especially if their insulin resistance is caught early. Clinical practice suggests that for some people, eating a low-carb diet, losing weight and getting insulin levels down will restore insulin sensitivity and may allow them to regain the degree of metabolic flexibility found in healthy individuals.26

That metabolic flexibility may allow them to increase the amount of carbs they can safely eat from 20 grams per day up to 75 grams, or it may allow them to reduce the amount of exercise they need to keep blood sugar and insulin levels low.27

In addition to maintaining weight loss, regular blood tests may be required to determine who will achieve metabolic flexibility and how much flexibility they can “get away with” without triggering the cycle of insulin resistance again.

So the best advice may be to stay with the most intensive lifestyle change you can maintain and be vigilant about continual screening for recurrence of insulin resistance. This starts with keeping an eye on your waist size, but also may include regular (every 6-months or so) blood tests for fasting insulin and fasting glucose.

See our companion guide: What you need to know about insulin resistance, which discusses diagnostic tests.

You can also measure your post-meal blood sugar levels after a low-carb meal and a moderate-carb meal and compare the readings. If a moderate carb meal causes your blood sugar to go over 140 mg/dl (7.8 mmol/L), that could be a sign that you may still be insulin resistant.28 Note that this is just an expert opinion, and not based on hard data.

Woman with diabetes checking her blood glucose using her glucose meter

What you need to know about blood sugar

Guide If you have a diagnosis of diabetes, you’ve probably been tracking your blood sugar for years. But if you’ve recently decided to try a low-carb or ketogenic diet, you may need to understand your results in the context of your new dietary pattern.


Summary

Insulin is important for survival and good long-term health but chronically high insulin levels make your body less responsive to this essential hormone, which might increase your risk of developing serious chronic health conditions.29

Adopting effective lifestyle changes — like a low-carb, ketogenic diet, regular physical activity, and a good sleep routine — can lower insulin levels and reduce insulin resistance.

/Dr. Bret Scher, MD


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  1. The Clinical Biochemist Reviews 2005: Insulin and insulin resistance
    [overview article; ungraded]

  2. Diabetes & Metabolism 2003: Reducing insulin resistance with metformin: the evidence today [review article; ungraded]

  3. Nutrition & Diabetes 2017: Enhanced insulin sensitivity in successful, long-term weight loss maintainers compared with matched controls with no weight loss history [case control study; weak evidence]

  4. Journal of the American College of Nutrition 2013: Improvements in glucose metabolism and insulin sensitivity with a low-carbohydrate diet in obese patients with type 2 diabetes [uncontrolled study; weak evidence]

  5. Annals of Internal Medicine 2005: Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes [case series study; weak evidence]

  6. Journal of the American Medical Association 2010: A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss [moderate evidence]

  7. Science of Translational Medicine 2015: Excessive caloric intake acutely causes oxidative stress, GLUT4 carbonylation, and insulin resistance in healthy men [uncontrolled intervention trial; weak evidence]

  8. Nutrition Review 2014: Time-restricted feeding and risk of metabolic disease: a review of human and animal studies [overview article; ungraded]

  9. Nutrition Review 2014: Time-restricted feeding and risk of metabolic disease: a review of human and animal studies [overview article; ungraded]

  10. Journal of Applied Physiology 2005: Effect of intermittent fasting and refeeding on insulin action in healthy men [uncontrolled intervention trial; weak evidence]

  11. International Journal of Obesity 2011: The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women [moderate evidence]

  12. Arteriosclerosis, Thrombosis and Vascular Biology 2007: Physical inactivity rapidly induces insulin resistance and microvascular dysfunction in healthy volunteers [uncontrolled intervention study; weak evidence]

  13. Medicine and Sport Science 2014: Sedentary behavior as a mediator of type 2 diabetes [overview article; ungraded]

  14. British Medical Journal Open Sport Exercise Medicine 2016: Update on the effects of physical activity on insulin sensitivity in humans [overview article; ungraded]

  15. Journal of Obesity and Weight Loss 2015: Exercise training and insulin resistance: A current review [overview article; ungraded]

  16. Clinical Endocrinology 2003: Obstructive sleep apnoea syndrome impairs insulin sensitivity independently of anthropometric variables [cohort study; weak evidence]

  17. European Respiratory Journal 2010: A randomised controlled trial of nasal continuous positive airway pressure on insulin sensitivity in obstructive sleep apnoea [moderate evidence]

  18. Journal of Endocrinology 2013: Acute psychological stress results in the rapid development of insulin resistance [mouse study; very weak evidence]

  19. PLoS One 2016: Tobacco use, insulin resistance, and risk of type 2 diabetes: Results from the multi-ethnic study of atherosclerosis [prospective cohort study; weak evidence]

  20. This is based on consistent clinical experience. [weak evidence]

  21. This is based on consistent clinical experience. [weak evidence]

  22. [expert opinion; no evidence]

  23. International Journal of Cancer 2017: Association between hyperinsulinemia and increased risk of cancer death in nonobese and obese people: A population‐based observational study [observational study with HR < 2; very weak evidence]

    The New England Journal of Medicine 1996: Hyperinsulinemia as an independent risk factor for ischemic heart disease [observational study with HR < 2; very weak evidence]