Insulin is a hormone produced by your pancreas. Its job is to act like a key, unlocking your cells so they can absorb glucose (sugar) from your bloodstream and convert it into energy.
How insulin resistance develops
When you eat, especially carbohydrates, your blood sugar rises and your pancreas releases insulin to move that sugar into your cells. When everything is working well, blood sugar returns to normal after eating.
With insulin resistance, your cells stop responding to insulin the way they should. Here's what happens:
Blood sugar rises after eating
Your pancreas releases insulin, but your cells don't respond well
Your pancreas compensates by producing more insulin
Over time, your cells become increasingly resistant
Eventually, your pancreas can't keep up, and blood sugar stays elevated
When blood sugar levels are higher than normal but not yet high enough for a diabetes diagnosis, this is known as prediabetes. Left unaddressed, prediabetes can progress to type 2 diabetes.
Risk factors
You can't always tell if someone has insulin resistance just by looking at them. Common risk factors include:
Excess body weight, especially around the abdomen
Physical inactivity (less than 3 times per week)
A diet high in processed foods, carbohydrates, and saturated fats
Family history of type 2 diabetes
Age (45 and older are at higher risk)
High blood pressure, high triglycerides, or low HDL cholesterol
Symptoms
Insulin resistance often has no symptoms and can go undetected for years. Some signs that may appear over time include:
Fatigue
Increased hunger or thirst
Difficulty losing weight
Dark patches of skin (called acanthosis nigricans), often on the neck or armpits
The most reliable way to know is through blood testing. Common tests include:
Fasting glucose: Prediabetes range is 100 to 125 mg/dL
A1C test: Prediabetes range is 5.7% to 6.4%
Oral glucose tolerance test (OGTT): Prediabetes range is 140 to 199 mg/dL
The good news: it can be reversed
Research shows that lifestyle changes can cut the risk of progressing to type 2 diabetes by up to 58%. Key steps include:
Move more: Aim for at least 150 minutes of physical activity per week (about 30 minutes, 5 days a week)
Eat well: Focus on whole foods like vegetables, fruits, whole grains, and lean proteins. Reduce processed foods and added sugars
Manage weight: Losing just 5 to 7% of body weight can make a significant difference (that's about 10 to 14 lbs for someone weighing 200 lbs)
Sleep and stress: Getting enough quality sleep and managing stress also support insulin sensitivity
How Theia can help
A CGM (continuous glucose monitor) gives you real-time visibility into how your body responds to the foods you eat, your activity levels, and your daily habits. By tracking your glucose patterns with Theia, you can:
Identify which foods cause spikes and which keep you stable
See how exercise, sleep, and stress affect your blood sugar
Make informed, data-driven changes to improve your metabolic health over time
You can learn more about glucose in our Glucose Overview article.
Need Help?
Our team is always happy to assist. Reach us at [email protected] or through our in-app messenger.
Sources: NIDDK, CDC, Mayo Clinic, Cleveland Clinic