Insulin resistance is a common, almost silent condition in which the body's tissues stop responding effectively to the hormone insulin. 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.
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. 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. But if you want to make the largest impact, the low-carb, ketogenic diet may be better than the others.
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. 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.
In two other studies, a very-low-carbohydrate diet was better at lowering insulin levels than a low-fat diet. 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. 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.
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.
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:
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. 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.
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. Another trial showed better improvements in insulin resistance among women using intermittent caloric restriction (fasting) compared to chronic caloric restriction.
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. Multiple studies show that long-term inactivity is strongly associated with insulin resistance, metabolic syndrome and pre-diabetes.
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.
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. 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. A chronic sleep disturbance, such as from obstructive sleep apnea, is also associated with worsening insulin resistance.
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.
Stress
Studies show temporary insulin resistance arises during periods of short term physiological and psychological stress, such as a sudden illness or sudden threat. 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. 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. 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.
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.
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.
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. Note that this is just an expert opinion, and not based on hard data.
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.
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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