The 5 Best Whole Grains to Help Improve Insulin Resistance, Recommended by Dietitians

Our body naturally knows how to digest food. It breaks down carbs into glucose, the body's preferred energy source. The pancreas makes the hormone insulin and releases it to the bloodstream, supporting body cells to uptake the glucose. 

According to the National Institute of Diabetes and Digestive and Kidney Diseases, insulin resistance occurs when body cells ignore or don't respond well to insulin. The glucose from food stays in the bloodstream, triggering the pancreas to make more insulin for the body cell receptors to respond and allow glucose to enter into the cells. 

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The National Health and Nutrition Examination Survey from 2021 estimates that 40% of U.S. adults ages 18 to 44 have insulin resistance. You may not know you have it unless you go for routine bloodwork to check your blood sugar levels, since you may or may not show symptoms related to insulin resistance.  

High-carb foods, such as cereals and grains, are often under scrutiny when managing health. Cereals and grains also come with the misconception that they are also loaded with sugar and can spike blood sugar levels, potentially straining the body's insulin response over time.

Still, the registered dietitians (who are also certified diabetes educators) we spoke with indicate that consuming high-carb foods like whole grains and whole-grain cereals with minimal added sugars and rich in fiber and protein, in moderation, can be a viable part of a balanced diet for managing insulin resistance. Keep reading to discover how, and the types of whole grains that improve insulin sensitivity.

How Whole Grains Improve Insulin Resistance

While whole grains are rich in soluble and insoluble fiber, the former may have a more pronounced effect in stabilizing blood sugar levels and increasing insulin sensitivity, per a 2020 study published in Nutrients.

When you eat whole-grain foods packed with soluble fiber, the fiber mixes with food by absorbing water and forming a gel. This gel-like property limits the food’s contact with the absorbent surfaces in the digestive tract, consequently slowing down digestion and how fast glucose is absorbed.

At the same time, the presence of soluble fiber prompts the production and release of a digestive-related hormone called glucagon-like peptide-1 (GLP-1) in the intestines, per ScienceDirect. Michelle Routhenstein, M.S., RD, CDE, CDN, owner of Entirely Nourished, explains, "In response to food intake, this hormone helps improve [glucose tolerance and] insulin sensitivity by enhancing insulin release, slowing stomach emptying to regulate blood sugar metabolism." Routhenstein and Jonathan Valdez, M.B.A., RDN, CDN, CCM, CDCES, ACE-CPT, owner of Genki Nutrition, also note that fiber feeds the good bacteria in the gut. 

Valdez adds that gut-friendly bacteria produce short-chain fatty acids. These SCFAs are then absorbed into the body, supporting the nerves involved with glucose and cholesterol regulation. A 2023 review from Nutrition Reviews also concluded that eating foods with soluble fiber, such as whole grains, in moderation, may boost the production of SCFAs and improve insulin sensitivity.

5 Best Whole Grains for Insulin Resistance

Based on our research and dietitians' recommendations, we have compiled a list of the five best whole grains that can help improve insulin sensitivity.

1. Oats

 Oats are an excellent source of soluble fiber, particularly beta-glucan, a type of soluble fiber shown in bodies of research to prevent blood sugar spikes, improve insulin sensitivity and lower LDL cholesterol. A clinical study from 2021 in the Journal of Functional Foods also found that eating 5 grams of beta-glucan from oats daily for 12 weeks significantly improved hemoglobin A1C, a marker for blood sugar control over three months.

According to the USDA, you will find almost 4 grams of beta-glucan in every 100-gram serving (about 3.5 ounces) of steel-cut oats. Beta-glucan also gives cooked oats their viscous and thick texture. Use oats as a binder in meat and veggie loaves, such as our Old-Fashioned Meatloaf, or as a thickener to make fluffy Oatmeal Pancakes with Maple Fruit. 

Pulse oats into a breadcrumb-like texture, like panko, to coat meats. This is an excellent hack for added fiber and nutrients if you run out of whole-wheat panko for casseroles and baked chicken.

2. Barley

Barley is another whole grain full of soluble fiber, with one study from 2019, published in Food Science & Nutrition, estimating the grain contains 5 grams of soluble fiber per 100-gram serving. 

Like oats, barley also has beta-glucan, which a 2020 study from Clinical Nutrition Research noted may positively impact post-meal blood glucose levels and promote insulin sensitivity (how efficiently your body responds to insulin), potentially due to it delaying digestion and absorption.

Barley makes an excellent side dish and a hearty addition to porridges, soups, stews, salads and breakfast bowls. It has a chewy texture that absorbs flavors well. One of our favorites is pairing barley with steelhead trout and a side veggie for a balanced and nutritious meal.

3. Quinoa

Quinoa may not be the first grain that comes to mind when you think of fiber, but this fluffy-textured grain deserves the spotlight.  

A 2023 study published in Frontiers in Physiology involved 138 participants with impaired glucose intolerance who were randomly divided into control and quinoa-intervention groups as part of a one-year study. The researchers found that, compared to the control group, those with quinoa added as a staple to their intake had improved post-meal blood sugar levels and insulin sensitivity and delayed progression from impaired glucose tolerance to diabetes.  

These findings could be related to the whole grain's fiber content, since it's packed with 5 grams of fiber per 1-cup cooked serving. Quinoa's also rich in protein, so you may feel full for longer since protein also helps slow down digestion, as fiber does.

Quinoa is delicious as a side dish, a base for salads and casseroles and an ingredient mixed into stir-fries. Because quinoa is mild in flavor, it can absorb sweeter notes from foods like carrots, cinnamon and raisins, or savory flavors with fresh herbs like parsley and dill. Our 17 Best Quinoa Dinner Recipes are great for meal inspirations!

4. Buckwheat Groats

Buckwheat groats, also known as kasha, are the seeds of the buckwheat plant. Per the USDA, 1 cup of cooked roasted groats offers almost 5 grams of fiber.

Including buckwheat groats as part of a balanced meal pattern could prevent the roller coaster of blood glucose levels, improving insulin sensitivity and reducing A1C, notes a 2023 Food Science & Nutrition review. 

Another review from 2022 in the Journal of Personalised Medicine indicated that eating buckwheat regularly may also be linked to lowered fasting blood glucose levels. 

Toasted whole buckwheat groats are nutty and crunchy, and when cooked their texture is similar to rice. You can add buckwheat groats to porridges, granola, pancakes, salads, pilafs, risottos and meat dishes. If you have a sweet tooth, make some filling muffins with roasted groats.

5. Brown Rice

 While rice often gets a bad rap for raising blood sugar levels, there are reasons why brown rice is on our list.

First starters, brown rice is a whole grain with 3 grams of fiber per 1-cup serving.

While eating brown rice doesn't appear to lower fasting blood sugar levels and improve A1C levels, it can help slow down the digestion and absorption of carbohydrates, contributing to lower post-meal glucose levels and improved insulin sensitivity, per a 2022 review from Comprehensive Reviews in Food Science and Food Safety.

Brown rice is a versatile ingredient with mild flavor; use it as a base for savory rice bowls, pilafs and desserts like Mango Sticky Brown Rice. 

How Much Whole Grains Should You Eat to Improve Insulin Sensitivity?

 Routhenstein suggests aiming for three to five servings of diverse whole grains daily, which can contribute to improved insulin sensitivity. Since individual needs may vary, consulting a registered dietitian for personalized dietary advice is recommended.

Other Tips to Lower Insulin Resistance

 While eating a variety of whole grains is key to combating insulin resistance, the complexity of the condition goes beyond this, and your overall diet, sleep, stress, lifestyle choices, genetics and more can play a role:

• Include Plant-Based Foods: Incorporating a variety of plant-based foods may lower the risk of type 2 diabetes, per a 2019 study from JAMA Internal Medicine.
• Stay Active: The American Diabetes Association notes that staying active could improve your body's sensitivity to insulin for 24 hours or more after the activity. The ADA recommends staying active for at least 150 minutes each week.
• Develop a Sleep Routine: A good night's sleep is about more than just getting enough rest; it can also impact your body's insulin sensitivity, per the Centers for Disease Control and Prevention. To get a restful night, develop a bedtime routine that can help you sleep for seven or more hours each night, such as keeping your room dark, limiting caffeine in the afternoon and evening and avoiding screen time before sleep.

The Bottom Line

Eating whole grains rich in soluble fiber, such as oats, barley, quinoa, buckwheat groats and brown rice in moderation and regularly, along with a diverse range of nutritious foods, may help improve insulin sensitivity. Keep in mind that addressing insulin resistance requires a multifaceted approach, including focus on your activity level, sleeping habits and other lifestyle factors—start the discussion with your doctor or registered dietitian today!