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Weight Loss

Insulin Resistance: The Main Reason You Aren’t Losing Weight

8 minutes read

If you’ve been struggling to lose weight despite dieting and exercising, insulin resistance might be to blame. According to a recent study, 4 in 10 young American adults without diabetes have insulin resistance, which has been strongly associated with adult weight gain [1, 2].

As a condition that impacts millions of non-diabetic Americans each year, insulin resistance (or impaired insulin sensitivity) can lead to weight gain as well as other more serious side effects in the long term.

What is insulin resistance?

Insulin resistance occurs when the cells in your body stop responding properly to insulin, a hormone in your pancreas that regulates blood glucose levels.

Normally, the food you eat is converted into glucose (your body’s preferred energy source), which enters your bloodstream and lets the pancreas know that it’s time to release insulin. But when too much blood sugar enters the bloodstream, the pancreas has to pump out larger-than-anticipated amounts of insulin.

Eventually, the cells become desensitized to this excess amount of insulin and stop responding properly, resulting in higher-than-normal blood glucose levels.

What causes insulin resistance?

Anyone can develop insulin resistance, but lack of physical activity, large waist circumference, and high total fat mass all appear to be contributing factors [3, 1]. Another contributing factor, and perhaps the most impactful, is diet — specifically, a diet high in processed foods, added sugar, refined carbohydrates, and low-quality fat has been strongly associated with the development of insulin resistance [4].

Some of the most common side effects of insulin resistance include weight gain, difficulty losing weight, blood sugar spikes after eating, extreme hunger or thirst, and tiredness.

However, most people don’t experience symptoms of insulin resistance at all. Over time, insulin resistance can lead to prediabetes and type 2 diabetes, as well as an increased risk of adverse cardiovascular events and all-cause mortality [1].

graphic showing the cycle between weight gain and insulin resistance

The relationship between insulin resistance and weight gain

Insulin resistance can lead to weight gain, and vice versa, in a positively reinforcing loop. One study of 6,671 men and women found that adult weight gain was associated with more adipose tissue (excess weight that develops around the center of the body) and triglycerides in your liver in middle age, contributing to insulin resistance [5, 6].

But how does this all work?

Your pancreas and liver play a crucial role in regulating blood sugar levels. Under normal circumstances, when your body’s insulin sensitivity isn’t impaired, your pancreas releases insulin after a meal, which unlocks your cells so they can take in the glucose from your bloodstream and convert it into energy.

At the same time, increased insulin levels also signal the liver to store excess glucose to use as energy later (in the form of glycogen). Any excess glucose is stored as fat [7]. When you’re sleeping or not eating and your body needs to produce energy, your liver will release glucose into your blood for your cells to use [8].

That all changes when you have insulin resistance: your cells don’t respond properly to insulin, leading to elevated glucose (and insulin) levels in the blood — which promote fat storage in your liver.

When your liver accumulates extra fat, it becomes increasingly less sensitive to insulin and pumps additional glucose into your blood when it shouldn’t, triggering your pancreas to release even more insulin to bring those glucose levels back down [9]. These high insulin levels lead to increased fat storage, starting the cycle over again.

If you’re experiencing this self-perpetuating cycle of weight gain/higher insulin levels, it may become harder and harder for you to manage a healthy weight.

In a 2022 study, researchers performed two trials where young-to-middle-age participants consumed a calorie-restricted diet with either low or moderate carbohydrates — with the goal of 10-14% weight loss within 10 weeks or 12-18% weight loss within 14 weeks, respectively [10].

They learned that subjects who were more insulin resistant tended to lose less fat mass and more muscle mass than participants who were not insulin resistant.

This isn’t to say that you can’t lose weight effectively if you have insulin resistance, but it means that you have to address the root of the problem: balancing your blood glucose levels and lowering circulating insulin levels. When you shift your focus like this and make resolving insulin resistance your objective, losing weight not only becomes easier but is a natural side effect of the process.

Is insulin resistance reversible?

The good news is that insulin resistance is reversible. If you think you may have insulin resistance, you can talk with your doctor and get a blood test (typically a fasting plasma glucose test, oral glucose tolerance test, or hemoglobin A1C test) to check your blood sugar levels.

You can also get an “insulin in blood” test, which measures the amount of insulin in your blood, though this isn’t a typical test that your doctor orders in blood panels since there is a lack of consensus about normal insulin levels.

Once you know for sure whether you have insulin resistance (or are at an increased risk for it), you can take the needed steps to get it under control.

How to reverse insulin resistance and lose weight

Insulin resistance is a two-part problem: too much glucose in your blood and a lack of insulin sensitivity. In the same way that both diet and non-diet factors can lead to insulin resistance, reversing the condition involves making shifts across your lifestyle, including the Four Pillars of Metabolic Health: diet and nutrition, exercise, sleep, and stress management.

1. Eat an insulin-resistance-friendly diet

One of the most simple and effective ways to stabilize your glucose levels and reverse insulin resistance is to change your diet. This means opting for whole fruits and vegetables instead of refined carbohydrates such as processed bread and sugar, which tend to have a high glycemic index that triggers glucose spikes. It also means understanding the principles behind an insulin-resistance-friendly plate, which Ali McGowan, MS, LD, RDN, has outlined in four simple steps:

Eating at least five servings per day of colorful fruits and vegetables, which are high in phytonutrients and anti-inflammatory compounds.
Prioritizing lean protein, which can help blunt blood sugar spikes and support lean muscle mass and healthy body composition.
Choosing healthy fats (like extra-virgin olive oil, nuts/seeds, etc.) that can help improve the bioavailability of key nutrients and keep us full for longer.
Getting enough fiber, key for microbiome health (which can help with weight loss) and stabilizing glucose levels.

For a complete grocery shopping list that is insulin-resistance-friendly, check out our dietitian-created Mediterranean diet grocery list.

But diet isn’t just about what you eat, but when you eat it — in other words, being more thoughtful about meal timing and food order. For instance, eating a fiber-rich salad before consuming carbohydrates can help minimize a glucose spike, and experimenting with time-restricted eating patterns can help you better align your meal schedule with your circadian rhythm (your body’s internal clock) and is linked with weight loss.

2. Do exercises that help reverse insulin resistance

Exercise — particularly a combination of resistance training and aerobic exercise — has been linked to improved insulin sensitivity. A review of 11 studies found a connection between increased physical activity levels and lower chances of developing insulin resistance [11].

Another study found that insulin sensitivity increased for at least 16 hours in both healthy subjects and those with type 2 diabetes after exercise [12].

The five best exercises to do for insulin resistance and weight loss are walking, squats, swimming, burpees, and yoga. Current exercise guidelines suggest that adults should do:

150-300 minutes (2.5-5 hours) per week of moderate-intensity exercise or 75-150 minutes (1.25-2.5 hours) per week of vigorous-intensity aerobic physical activity.
2 sessions per week of resistance training or muscle-engaging workouts.

Ultimately, all exercise, when done consistently, is a key tool in reversing insulin resistance — choose the type of workout and the time of day that’s easiest for you to stick to.

3. Manage stress levels, which can increase insulin resistance

Cortisol, the stress hormone, is critical to survival — but chronic stress can interfere with the role that insulin plays in your body. That’s because the two hormones are antagonistic: cortisol temporarily decreases insulin sensitivity and increases glucose production in the liver so your body has a readily available source of quick energy.

When your cortisol levels are consistently high, your blood sugar levels also stay elevated. One study of 766 workers in China found that chronic stress was “associated with insulin resistance and may contribute to the development of insulin resistance” [13]. High cortisol and stress can also lead to weight gain by changing the way you perceive food, leading to cravings for high-calorie, sugary snacks.

If you’re not sure how to reduce stress, you might want to incorporate sauna sessions or yoga into your routine — one 16-person study found that yoga, mindfulness, and a mobile mindfulness application helped participants manage stress levels [14].

Here are some other tips to manage stress:

Breathwork (counting to four as you inhale, then counting to four as you exhale)
Low-intensity exercise, like walking and yoga
Spending time in nature
Avoiding processed foods
Getting good rest
Finding social support in the form of community

4. Get enough sleep

Consistently poor sleep — both sleep deprivation and an irregular sleep schedule — can take a significant toll on your insulin sensitivity. One study found that not getting enough sleep for just one night induced insulin resistance in healthy subjects [15].

Fortunately, catching up on rest can reverse the effects of poor sleep on insulin resistance. To improve your sleep hygiene, try the following tips:

Go to bed at the same time each night
Reduce blue light exposure in the evening
Avoid caffeine after 2 p.m.
Make your bedroom as dark and quiet as possible

5. Track your glucose levels with a CGM

Incorporating these tips into your routine can help you stabilize your glucose levels and improve your insulin sensitivity, with or without a continuous glucose monitor (CGM). But metabolic health isn’t black and white — it’s a spectrum, and a lot can happen between having peak metabolic health and having insulin resistance. The only way you can understand where you fall on the metabolic health spectrum is by using a CGM. Paired with an app like Veri, a CGM can give you personalized insights about your glucose trends and variability, allowing you to understand how your body responds to your diet and lifestyle. In other words, you can see how food, exercise, sleep, and stress affect your real-time glucose levels, and their relationship to your mood and energy levels. Empowered with this knowledge, you’re then able to build better metabolic habits, improve your quality of life, and reverse insulin resistance.

Key takeaways

Insulin resistance can be scary. But, like with anything else in life, knowledge is power. Here’s what to keep in mind about insulin resistance:

Insulin resistance occurs when cells stop responding to insulin, which causes too much blood sugar to circulate in the bloodstream. This leads to a vicious cycle where insulin resistance contributes to weight gain, further reducing insulin sensitivity.
To lose weight that’s due to insulin resistance, you need to fix insulin resistance first. This means stabilizing your glucose levels and improving your insulin sensitivity.
Experimenting with meal timing and eating a diet rich in complex, low-glycemic-index carbohydrates such as whole grains, non-starchy vegetables, and fresh fruit can help stabilize glucose levels.
A combination of resistance training and aerobic exercise can help improve insulin sensitivity.
Try sauna and yoga to lower your stress levels, which may be keeping you in a state of insulin resistance.
Maintain a consistent sleep schedule and practice good sleep hygiene to improve insulin sensitivity.
Use a CGM to track your glucose levels and get personalized insights that help you improve your habits, reverse insulin resistance, and achieve your metabolic health goals.

References:

Written by: Rebekah B.

Reviewed by: Emily Johnson, MSc RD

Table of Contents

What is insulin resistance?
What causes insulin resistance?
The relationship between insulin resistance and weight gain
Is insulin resistance reversible?
How to reverse insulin resistance and lose weight
Key takeaways

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