What Is the Main Cause of Insulin Resistance?

The main causes of insulin resistance include obesity, a waist measurement of 40 inches or more for men and 35 inches or more for women, and physical inactivity.

Insulin is a hormone made by the pancreas that works in the body to help regulate blood sugar, control metabolism, and regulate cellular growth. 

Insulin resistance occurs when the body's cells become resistant to the effects of insulin. The result is that the body needs higher levels of insulin to function properly.

The pancreas tries to offset this need by producing more insulin until it can no longer produce what the body needs and blood sugar levels rise. This increases the risk for diabetes and heart disease.

Three Main Causes of Insulin Resistance

• Obesity, especially excess fat in the abdomen and around the organs (visceral fat), a main cause of insulin resistance.
• A waist measurement of 40 inches or more for men and 35 inches or more for women is linked to insulin resistance. 
• Physical inactivity is another main cause of insulin resistance. 

Other causes of insulin resistance include: 

• Metabolic syndrome 
  • Excess weight (particularly around the waist)
  • High blood pressure
  • High cholesterol and triglycerides
• Genetic factors 
• Steroid use
• Older age
• Smoking
• Certain medications 
• Pregnancy
• Infection or severe illness
• Stress
• Sleep problems, such as sleep apnea

Risk factors for developing insulin resistance include:

• Age over 40 years 
• Ethnicity: Latino, African American, Native American, or Asian American
• A history of high blood pressure, high blood triglycerides, low HDL cholesterol, arteriosclerosis (or other components of the metabolic syndrome)
• Having close family members with type 2 diabetes, high blood pressure, or arteriosclerosis
• Past gestational diabetes
• Polycystic ovarian syndrome (PCOS)
• Acanthosis nigricans