People with health conditions like type 2 diabetes, gestational diabetes or polycystic ovarian syndrome may have been advised about the value of an insulin-resistance diet.
But this way of eating can benefit most people interested in balancing blood sugars, whether that's to help treat or prevent chronic conditions, or just to gain more energy and better mood control.
"An 'insulin-resistant diet' is a diet or eating plan that supports balanced blood sugars in the body," explained Rahaf Al Bochi, a registered dietitian and owner of Olive Tree Nutrition in Duluth, Ga.
Insulin is a hormone produced by the pancreas that helps sugar (glucose) from the bloodstream enter into cells, explained Al Bochi, who is also a spokeswoman for the Academy of Nutrition and Dietetics.
"When cells don't respond to insulin anymore, they are 'insulin resistant' and blood sugars can rise," she said.
The American Diabetes Association (ADA) explains it this way: Some people build up a tolerance to insulin, requiring more to get muscle, fat and liver cells to take up glucose. It can be chronic or temporary, according to the Cleveland Clinic.
Why this develops is not clear, but reasons can include genes, age, inflammation, other physiological stress and some medications. Lifestyle, too, such as being inactive or overweight can play a role.
A recent study of hibernating bears may eventually improve understanding about human diabetes, especially type 2, which is the most common form in people. Insulin resistance is a precursor to that disease and is affected by obesity and inactivity.
But a person doesn't have to be overweight to have insulin resistance, according to the U.S. Centers for Disease Control and Prevention.
What is a diet for insulin resistance?
The best diet for insulin resistance aims to pair carbohydrate foods with protein and fat, Al Bochi said.
Protein and fat foods might include meat, chicken, fish, cheese, avocado, oil, beans, nuts and seeds. Carbohydrates could include bread, pasta or a range of other items, such as dairy or fruit.
Blood sugar rises more slowly when protein, fat and carbs are eaten together compared to just eating carbohydrates on their own, Al Bochi said.
A 2019 research review published in Advances in Clinical and Experimental Medicine noted an emphasis on reducing intake of simple sugars from sweet drinks, desserts and excessive fruit juice.
"Many studies have demonstrated the beneficial effects of consuming complex, low-glycemic-index carbohydrates that are rich in dietary fiber," the review noted. "An insulin-resistant patient's diet should be rich in whole grains and high amounts of non-starchy vegetables and raw fruit."
Health benefits of an insulin-resistance diet
No single test will indicate whether someone is insulin-resistant, according to the CDC. A health care provider may make that diagnosis if a person has high blood sugar; a high level of triglycerides in their blood; a high level of "bad" (LDL) cholesterol; or low level of "good" (HDL) cholesterol.
A good indicator of how many people have insulin resistance is to note how many have prediabetes. That's about one-third of adults, more than 84 million people in the United States, according to the Cleveland Clinic.
A person can improve their insulin resistance with a healthy diet, regular moderate-intensity physical activity and weight loss, the clinic suggests.
These lifestyle modifications can reduce insulin resistance over time; lower blood glucose levels; and decrease blood pressure and bad cholesterol, while raising good cholesterol, according to the clinic.
How to balance your plate
Aim for a plate that is half vegetables, one-quarter carbohydrates and one-quarter protein and fat, Al Bochi said.
Vegetables should be non-starchy, the ADA's Diabetes Plate Method recommends.
Al Bochi offered an example of a food combination for insulin resistance: Adding avocado and egg to a person's morning toast will balance blood sugar by pairing the fat and protein with the carbohydrate.
"Choose fiber-rich foods such as vegetables, fruits, whole grains, beans and nuts because these can also help lower blood sugars," Al Bochi suggested.
Eating foods that have a low-to-moderate glycemic index (GI) can also help manage insulin resistance, according to the Cleveland Clinic.
Low-GI foods are beans, legumes, apples, berries, asparagus, cauliflower, leafy greens, other non-starchy veggies, nuts, dairy, fish and meat. High-GI foods include white bread, potatoes, breakfast cereals, cakes, cookies, watermelon and dates, among others.
Insulin-resistance diet food list
So, what specific foods should you eat?
While the list of non-starchy veggies is long, some examples are broccoli, Brussels sprouts, carrots, pea pods, tomatoes and peppers, the ADA suggests.
Protein sources can include lean meats, fish or even cheese in small amounts, as well as plant-based foods, such as beans, hummus, lentils, peas or tofu.
Fruit choices are plentiful, but they are considered a carbohydrate.
Sources of monounsaturated fat include avocado, canola oil, olive oil, olives, peanuts and peanut oil, safflower oil and some nuts, according to the ADA.
Polyunsaturated fat sources can include oily fish, walnuts, flaxseeds and chia seeds, tofu, eggs and sunflower seeds.
Al Bochi also suggests consulting with a registered dietitian for personalized nutrition tips.