What Is Insulin Resistance?

Written by Alyson Powell Key
Medically Reviewed by Melinda Ratini, MS, DO and Michael Dansinger, MD on June 20, 2025
6 min read

Weight and insulin resistance are often connected. Insulin resistance happens when your body doesn’t respond to insulin as it should. Insulin is a hormone that helps glucose, or blood sugar, enter the cells of your body for energy. When cells don’t respond well to insulin (insulin resistance), your body will make more insulin. High levels of insulin in the bloodstream can lead to fat storage (especially around your belly), cause you to feel hungrier, and make weight loss more stubborn.

Doctors link insulin resistance to overweight and obesity, prediabetes, and type 2 diabetes. Keeping a healthy weight is one way to reverse the condition or lower your chances of getting it.

"This is a chicken-and-egg type situation," says Bree Willis, MD, a family doctor and medical director of Twin Health in Mountain View, CA. "In most individuals, the early stages of insulin resistance often precede visible weight gain, especially when driven by genetic predisposition, and things like chronic stress, poor sleep, or a high-refined carb diet."

So, while weight gain can worsen insulin resistance, the condition often makes you more prone to putting on extra pounds by altering hunger signals, fat storage, and energy use.

The longer you have insulin resistance, the tougher it becomes to lose weight, as your body becomes better at storing fat. Plus, extra belly fat also makes it harder for the body to use insulin properly, which leads to worse insulin resistance. You may first need to reverse the condition before you can lose weight.

Losing weight with insulin resistance often involves a combination of exercise, changes to your diet, and medication.

Metformin for insulin resistance

Metformin is a common medicine used to help your body respond better to insulin. If you have obesity, scientists have found that it can trigger weight loss by curbing your appetite and changing your gut microbiome. Metformin is not FDA-approved for weight loss, as its effects are uneven.

GLP-1s for insulin resistance

GLP-1 receptor agonists are medicines usually prescribed for type 2 diabetes. They mirror the GLP-1 hormone that your gut releases, which controls blood sugar levels, appetite, and slows digestion. Along with managing diabetes, these drugs also promote weight loss by helping you feel full for longer so you eat less. 

Insulin resistance diet

The food you eat plays a role in your blood sugar and insulin levels. Michelle Routhenstein, a registered dietitian nutritionist and certified diabetes educator, suggests "getting away from fad diets." Routhenstein, who also owns Entirely Nourished in New York City, says losing weight with insulin resistance is about asking, "What is a balanced diet that allows for your body to achieve satiety? When you eat in a balanced way consistently throughout the day – every three to four hours – you’re helping your body digest the food, put it into a cell where it belongs, and not be overwhelmed so that it can do its job more effectively."

The glycemic index (GI) measures spikes in blood sugar based on foods with carbohydrates. High-GI foods contain a high amount of carbs or sugar, which quickly raise your blood sugar levels. You’ll then need a lot of insulin to lower your blood sugar. High-GI foods include:

  • Sugary drinks (regular soda and juice)
  • White bread
  • Potatoes
  • Breakfast cereals
  • Cakes and cookies
  • Certain fruits, such as dates

Low-GI foods lead to a more stable rise in your blood sugar levels. This means your pancreas doesn’t need to work as hard to make insulin. Low-GI foods include:

  • Beans and legumes
  • Certain fruits, such as apples and berries
  • Non-starchy vegetables (asparagus, cauliflower, and leafy greens)
  • Nuts
  • Dairy, fish, and meat

Talk to your doctor before making major changes to your diet.

Cardio for insulin resistance

Research shows that aerobic exercise, which can help you lose weight, works to improve insulin resistance. Regular activity can improve insulin sensitivity, allowing your cells to become better at using insulin to absorb glucose.

Strength training for insulin resistance

Resistance training could improve how your body uses insulin. This happens by building muscle mass, which makes you more able to store glucose. It also helps clear glucose from your blood and lowers the amount of insulin needed to keep your blood sugar levels normal.

Sleep hygiene

Not getting enough sleep, especially deep or restful sleep, can raise your blood sugar by increasing insulin resistance and stress hormones like cortisol. Here are some ways to get better sleep:

  • Go to bed at the same time every night, even on weekends.
  • Shut down phones, TVs, and computers at least an hour before bed.
  • Lower lighting in the evening to help your body wind down.
  • Aim for a room temperature of around 65 F.
  • Avoid caffeine, alcohol, and sugary drinks near bedtime.
  • Eat lighter at night to avoid sleep disruptions.
  • Exercise daily.
  • Do relaxing things before bed, such as reading or taking a bath.
  • Avoid working, watching TV, or scrolling in bed.

Stress management

Under stress, your body releases cortisol and adrenaline. These hormones make it hard for insulin to work properly, raising your blood sugar levels. Consistent stress can boost your chances of other problems with diabetes. 

To manage stress, make sure you’re getting enough sleep, exercise, and downtime. Talk to someone, such as a counselor or others with your condition, to feel less alone.

You may not have any symptoms of insulin resistance if your pancreas can make up for a shortfall of insulin, keeping your blood sugar levels normal. But if the condition continues to worsen and your blood sugar levels are regularly high, you could have the following symptoms:

  • Unexplained weight loss
  • Extreme tiredness
  • Increased thirst and hunger
  • Peeing a lot
  • Blurred vision
  • Yeast infections
  • Hyperpigmentation in your neck crease or armpits
  • Extra fat around your belly
  • Higher-than-normal fasting insulin and triglyceride levels
  • Lower HDL ("good cholesterol") levels
  • Fatigue, especially after meals
  • Strong sugar cravings
  • Polycystic ovary syndrome (PCOS) in women

What are the symptoms of insulin resistance in women?

In women or people assigned female at birth (AFAB), insulin resistance can appear even without obesity or overweight, especially in women living with PCOS, a condition where cysts form on your ovaries. 

You may notice an irregular period, acne, and facial hair, all signs of PCOS that happen even before an insulin resistance diagnosis. Insulin resistance that happens with PCOS can make it harder for women and people AFAB to lose weight.

What’s the relationship between PCOS and insulin resistance?

Research shows that insulin resistance is a major issue for people with PCOS, especially those who are overweight. Higher blood sugar levels can cause more stress on your body and trigger immune responses that may worsen PCOS symptoms.

Insulin is a hormone that helps move glucose, or blood sugar, into your body’s cells for energy. When your cells don’t respond well to insulin, known as insulin resistance, your body makes more insulin to try to fix the problem. High levels of insulin in your blood can lead to fat storage and make it harder to lose weight. Your diet plays a key role in insulin resistance. Other lifestyle changes to manage insulin resistance include getting enough exercise (both cardio and resistance training) and quality sleep, as well as lowering your stress levels.