It’s easy to blame sugar, but experts say the true cause of insulin resistance may start elsewhere.
Reviewed by Dietitian Lisa Valente, M.S., RD
Key Points
- Insulin resistance is a condition that raises blood sugar and can lead to diabetes.
- Oxidative stress alters how the body responds to insulin and damages cells that produce it.
- Lower oxidative stress by eating lots of fruits and vegetables, exercising and reducing stress.
Insulin resistance occurs when the body’s cells stop responding properly to insulin, the hormone responsible for moving glucose from the bloodstream into cells for energy. As a result, glucose and insulin can build up in the blood over time, increasing the risk for conditions like type 2 diabetes, metabolic syndrome and heart disease.
Globally, an estimated 1 in 4 adults may be affected by insulin resistance. And while many people assume sugar is the primary culprit, experts say the condition is far more complex. “Insulin resistance is caused by a combination of factors, including genetics, chronic stress, poor sleep, inactivity, excess visceral fat and smoking,” says Jess DeGore, RD, CDCES. “These factors contribute to oxidative stress and inflammation over time.”
While sugar and carbohydrate intake are important, here’s what to know about the connection between oxidative stress and insulin resistance, and the lifestyle habits that may help lower your risk.
Why Oxidative Stress Impacts Insulin Resistance
It Affects How the Body Responds to Insulin
Oxidative stress occurs when the balance in the body tips toward more harmful compounds than protective ones. As DeGore explains, “Free radicals occur naturally in the body, but issues arise when they accumulate faster than they can be cleared. This buildup leads to oxidative stress, which interferes with how cells respond to insulin, making it difficult to move sugar from the bloodstream into the cells for energy.”
Research suggests that when hyperglycemia, or elevated blood sugar, develops, the body produces higher levels of reactive oxygen species and increases inflammatory signaling. If the body is unable to clear glucose from the bloodstream, blood sugars remain elevated. Over time, this environment can disrupt normal insulin function and contribute to the development of insulin resistance, which may progress to other chronic health conditions.
It Can Damage Beta Cells That Produce Insulin
“Oxidative stress can damage the signaling pathways involved in insulin sensitivity and disrupt glucose homeostasis,” explains Kimberley Rose-Francis, RD, CDCES. These pathways are closely tied to pancreatic beta cells, which play a central role in regulating insulin. Rose-Francis notes that once these cells are damaged, insulin resistance can occur.
Research supports this connection, showing that impaired beta cell function is involved in the development of insulin resistance, prediabetes and type 2 diabetes. When cells become less responsive to insulin, the body may initially compensate by producing more of the hormone. Over time, this dysregulation can overwhelm beta cell function and disrupt normal signaling, ultimately contributing to the progression of insulin resistance.
Ways to Help Reduce Oxidative Stress
You can take proactive steps to help reduce oxidative stress through small, sustainable changes in your daily routine. These simple strategies may support healthier blood sugar levels and lower the risk of insulin resistance, while also helping you feel better overall.
- “Eat the rainbow” by including at least one serving of fruit or vegetables at every meal. Produce is rich in anti-inflammatory compounds that help fight free radicals. Rose-Francis adds, “Antioxidants, which are found in plant-based foods such as fruits and vegetables, protect the beta cells from oxidative stress by neutralizing them.” Try adding ½ cup of berries to breakfast, a side salad at lunch, or a small glass (about 2 ounces) of tart cherry juice with sparkling water as an evening mocktail; there are plenty of ways to boost antioxidant intake through everyday foods.
- Make movement part of your daily routine in a way that feels enjoyable. If running isn’t your thing, there’s no need to force it; walking, dancing, strength training and other forms of exercise all count. Research shows that regular physical activity can help reduce oxidative stress and improve endothelial function, both of which support insulin sensitivity.
- Build in stress-management practices that work for you. Chronic stress can contribute to insulin resistance, so finding ways to unwind matters. Yoga, meditation or even a walk outdoors can all help lower stress levels. Since life is unpredictable, having tools to manage stress can make a meaningful difference.
Our Expert Take
Insulin resistance develops over time and is influenced by a variety of factors, including genetics, physical activity, eating habits, sleep, smoking and body weight. But one contributor that often flies under the radar is oxidative stress. “Oxidative stress can damage the signaling pathways involved in insulin sensitivity and alter glucose homeostasis,” says Rose-Francis. Over time, these disruptions may make it harder for the body to regulate blood sugar effectively, increasing the risk of insulin resistance.
The good news is that small, consistent lifestyle habits can help lower oxidative stress and support metabolic health. Prioritizing antioxidant-rich foods like fruits and vegetables, staying physically active and managing stress can all play a role in protecting insulin sensitivity over the long term.
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