How to treat insulin resistance

Insulin resistance is a common, almost silent condition in which the body’s cells become less able to efficiently respond to the hormone insulin.¹ This causes the pancreas to secrete even more insulin to keep blood sugar from rising too high.

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.²

Eventually this may lead to pre-diabetes, type 2 diabetes, PCOS, 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.

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

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Can drugs help?

If you have been diagnosed with insulin resistance, your first question may be whether any medications can treat this condition. While the FDA has not approved any drugs specifically to treat insulin resistance, there are two commonly prescribed drugs for diabetes that can improve insulin sensitivity.

Many doctors prescribe metformin for patients with prediabetes and/or insulin resistance. It works by decreasing glucose production by the liver and increasing the insulin sensitivity of cells.³ However, it does not address the underlying cause of the insulin resistance.

Pioglitazone is another medication that lowers blood sugar by enhancing the body’s sensitivity to insulin.⁴ This drug tends to not be as popular as metformin, however, in part due to the potential side effect of mild weight gain.

Though drugs may play a role in improving insulin sensitivity and delaying the onset of type 2 diabetes, they are rarely adequate as a sole intervention. What else can you do if you have insulin resistance? This guide explores the lifestyle changes you can make as supported by the latest evidence.

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The low-carb diet

Practically any dietary intervention that results in weight loss, especially fat loss within the abdomen, can temporarily improve insulin sensitivity.⁵ A low-carb diet certainly fits this description, and may be more effective than low-fat diets for improving insulin sensitivity.⁶ One weak observational study even suggested improved survival for those with prediabetes who ate a lower carbohydrate diet, while a stronger nonrandomized trial reported glucose normalization in over 50% of participants with prediabetes.⁷

The reason why low-carb diets are good for people with insulin resistance is simple: if you are not eating sugar — or carbohydrates that rapidly digest to sugar — you will have less sugar entering your bloodstream and therefore less of a need to make insulin to move sugar (glucose) out of the blood and into cells.

If your body is already resistant to insulin, creating this internal environment in which high levels of insulin are not needed to maintain normal blood sugars is extremely helpful.

Studies show that a low-carb diet can be an effective diet for improving blood sugar control and achieving type 2 diabetes remission.⁸ Since insulin resistance plays a major role in causing type 2 diabetes, a low-carb diet is likely also good for addressing pre-existing insulin resistance before full-blown type 2 diabetes develops.

One short study in 2005 showed a 75% improvement in insulin sensitivity in ten patients with obesity and type 2 diabetes who went on a low-carb diet.⁹

In two other studies, a very-low-carbohydrate diet was better at lowering insulin levels than a low-fat diet.¹⁰ Of note, both groups in the latter study demonstrated equal weight loss, suggesting 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.¹¹ 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.

Finally, one study reports that people with insulin resistance have worse compliance with a low-fat diet, and better compliance with a low-carb diet.¹²

Takeaway: Reducing your intake of sugar and carbs that digest to sugar will likely result in reduced insulin production and improved insulin resistance.

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.¹³

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.¹⁴

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

• increasing protein intake¹⁵
• increasing dietary fiber intake¹⁶
• eating low-glycemic index foods¹⁷
• lowering dietary fat intake¹⁸

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

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

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Intermittent fasting/time-restricted eating

Intermittent fasting is a popular dietary trend that entails exactly what it sounds like: not eating during certain time periods. Though it may seem like a fad to some, studies suggest intermittent fasting can improve insulin sensitivity.¹⁹

Although not all studies agree. For instance, one RCT that did not control for how much or what the subjects ate, didn’t demonstrate a benefit in insulin sensitivity for those doing 16:8 time-restricted eating.²⁰ One lesson to draw from this is that what you eat and how much you eat is just as or likely even more important than when you eat.

There are multiple mechanisms by which fasting may improve insulin sensitivity. Cells can increase the number of insulin receptors on their surface, and those receptors can demonstrate an increased affinity for binding insulin during fasting.²¹

Also, various hormone levels increase during fasting and are thought to increase insulin sensitivity.²² For example, adiponectin – a fat-cell specific hormone – appears to enhance insulin sensitivity through increased fatty acid oxidation and inhibition of glucose production by the liver.²³

When it comes to implementing intermittent fasting, time-restricted eating is one type of fasting that involves eating meals within a set time-frame each day, such as between 11 am and 7 pm. A review of studies in healthy subjects showed that eating fewer meals during a shorter feeding window resulted in better glucose and insulin levels.²⁴

Another type of IF is alternate day fasting. 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.²⁵

Another trial reported greater improvements in insulin resistance among women using intermittent caloric restriction (fasting) compared to chronic caloric restriction.²⁶

Based on the fact that both fasting and low-carb diets have been shown to improve insulin sensitivity, we hypothesize that the combination of a low-carb 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 guide:

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 need to use much glucose, leading to a rise in insulin levels to process the excess blood sugar. Studies show that a mere five days of bed rest induces a state of insulin resistance in completely healthy volunteers.²⁷ Multiple studies show that long-term inactivity is strongly associated with insulin resistance, metabolic syndrome and pre-diabetes.²⁸

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.²⁹

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.³⁰ 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 partially, if not completely, counteract many of the benefits derived from exercise.³¹

Based on the evidence, it appears that the combination of regular exercise and a well formulated low-carb diet is an effective approach for treating insulin resistance and hyperinsulinemia.

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Sleep

Studies show that short-term sleep deprivation raises glucose levels and worsens insulin resistance.³² A chronic sleep disturbance, such as from obstructive sleep apnea, is also associated with worsening insulin resistance.³³

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 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.³⁴

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Stress

Studies show temporary insulin resistance arises during periods of short term physiological and psychological stress, such as a sudden illness or sudden threat.³⁵ In theory, this could have been an evolutionary advantage at some point in human existence and has been termed “adaptive insulin resistance”.³⁶ It makes sense that you would want to mobilize stored energy during infection, trauma, or stress, so inhibition of insulin (which stores energy) would be a good thing. This type of insulin resistance reverses when the sudden stress is over. Such a response to short-term stress likely has no long-term negative consequences.

However, it appears that chronic stress and chronic activation of the body’s fight or flight response will also lead to insulin resistance.³⁷ Since this chronic stress is longer-term, without a sudden onset or quick resolution of the trigger, it may lead to longer-term negative consequences.

Two small controlled studies demonstrated that meditation alone helped reduce blood sugar in patients with heart disease.³⁸ Since mindfulness training, yoga, meditation, dancing, singing, and walking in nature can be effective ways to reduce stress, increase wellbeing and improve overall physical health, they may also help with insulin resistance.

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

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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.³⁹

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Can we cure insulin resistance?

Once someone has dramatically improved their insulin resistance, bringing insulin and blood sugar levels down by eating a low-carb diet, and they have improved their exercise, stress management, and sleep, 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.⁴⁰

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.⁴¹

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.⁴²

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 stick with the most intensive lifestyle change you can maintain and be vigilant about 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 2-hour 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.⁴³ Note that this is our expert opinion, and not based on hard data.

Summary

Insulin and its proper functioning are important for survival and good long-term health. Obesity, metabolic dysfunction, and chronically high insulin levels make your body less responsive to this essential hormone, which might increase your risk of developing serious chronic health conditions.⁴⁴

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

/Dr. Bret Scher, MD