What Happens to Your Blood Sugar When You Eat Sweet Potatoes

You may think starchy foods like sweet potatoes are off-limits if you’re trying to stabilize your blood sugars, but that’s not the case. “Someone with blood sugar issues does not need to avoid sweet potatoes, as the fiber in sweet potatoes can help with reducing the absorption of sugar from meals,” says Rachel Pessah-Pollack, M.D., FACE. 

That said, pairing carbs—like sweet potatoes—with nonstarchy veggies, lean proteins and healthy fats is essential to slow carbohydrate absorption. We interviewed an endocrinologist and a diabetes dietitian to share how sweet potatoes impact blood sugars and a few blood sugar–friendly ways to eat them.

Impact of Sweet Potatoes on Blood Sugar

They Raise Your Blood Sugar

There’s no avoiding the fact that sweet potatoes will raise your blood sugar. “Sweet potatoes are a starchy vegetable, so physiologically their carbohydrates naturally raise post-meal glucose,” says Deepa Deshmukh, M.P.H., RDN, CDCES, BC-ADM. Don’t let that scare you away, though. Even if you have prediabetes or diabetes, you still need carbs for energy, and experiencing a rise in blood sugars is natural after eating. You just want to avoid a large, rapid spike in blood sugars. A big spike is more likely to happen if you top your sweet potatoes with sweets like sugar or marshmallows. Instead, add toppings rich in protein and fiber like beans, ground meat and nonstarchy veggies.

Their Fiber Helps Slow Carbohydrate Breakdown

“Sweet potatoes contain dietary fiber, which has great benefits for your gastrointestinal system and can help with absorbing glucose, slowing digestion and reducing blood sugar level elevations after eating,” says Pessah-Pollack. A medium sweet potato has about 4 grams of fiber—14% of the Daily Value—and 24 grams of total carbohydrates. “Their fiber, including pectin and resistant starch, slows gastric emptying and carbohydrate absorption, helping blunt the spike compared with lower-fiber starches,” adds Deshmukh. This rich fiber content makes sweet potatoes an excellent carb choice for better blood sugars. 

Their Resistant Starch May Improve Glucose Metabolism

As far as starchy veggies go, sweet potatoes are especially high in resistant starch—a fiber that resists digestion in the small intestine and makes it to your colon intact. There, it gets fermented by microorganisms, which produces short-chain fatty acids. These fatty acids help reduce inflammation and support glucose metabolism. Studies have found that including resistant starch in meals leads to lower post-meal blood sugars in people with prediabetes and type 2 diabetes.

How to Eat Sweet Potatoes for Better Blood Sugar

Leave the Skin On

Fiber is the most important component of sweet potatoes for preventing blood sugar spikes, and most of the fiber comes from the skin. “Leave the skin on for extra fiber (and potentially less of an increase in blood sugar),” says Pessah-Pollack. By eating the skin, you’ll reap more of the blood sugar–stabilizing benefits of sweet potatoes’ fiber and resistant starch.

Pair Them with Lean Protein and Nonstarchy Veggies

To manage diabetes, the American Diabetes Association recommends filling half your plate with nonstarchy veggies, one-quarter with protein, and one-quarter with carbs or starches like sweet potatoes.  This is also a balanced plate for people without diabetes. When assembling a meal with sweet potatoes, add a source of protein and plenty of nonstarchy veggies. This ensures you have a balance of carbs, protein and fiber for optimal blood sugar regulation. Lean proteins like chicken and salmon can be great choices for heart health and balancing blood sugars. Beans and lentils provide both fiber and protein, while nonstarchy veggies like broccoli, cauliflower, greens and mushrooms add fiber and nutrients without a bunch of carbs.

Try to Limit Sugary Toppings

Although sweet potatoes are undeniably delicious topped with marshmallows and brown sugar, these toppings are sources of added sugars. “Skip the sugar and marshmallows if you have diabetes or issues with sugar levels to prevent glucose spikes from these toppings,” recommends Pessah-Pollack. These toppings have a higher glycemic index, so they’re more likely to spike your blood sugars. If you do use sweet toppings, try reducing the amount you use, and pair it with sources of protein and fiber.

Let Them Cool 

Letting your sweet potatoes cool before eating them is a simple way to mitigate blood sugar spikes. “Cook–cool–reheat is believed to increase resistant starch, further moderating glucose rise,” says Deshmukh. You can enjoy them cold in salads or reheat them after you’ve let them cool. 

Tips for Enjoying Sweet Potatoes

• Add them to salads. Toss cooled, cubed sweet potatoes in your salads—like this Sweet Potato, Kale & Chicken Salad with Peanut Dressing. It’s an easy way to add complex carbohydrates and resistant starch, plus plenty of flavor to your salad.
• Make loaded sweet potatoes. There’s something comforting about a loaded potato. Not just that, but loading up your sweet potato provides an opportunity to add protein and nonstarchy veggies for better blood sugar regulation. For inspiration, check out this diabetes-friendly Chicken Curry Stuffed Sweet Potatoes recipe.
• Use them in grain bowls. Toss cubed sweet potatoes in your grain bowl for a source of carbohydrates and fiber. Bonus for blood sugars if you let them cool first! Split the carbs between sweet potatoes and a whole grain like quinoa. Then top the grains with proteins like chicken, salmon or tofu, and nonstarchy veggies like avocado, broccoli and kale.
• Experiment with different varieties. While you may be most familiar with orange sweet potatoes, there are lots of varieties to enjoy. “Explore purple, orange and Japanese white varieties for different textures, polyphenols, vitamins and antioxidants,” says Deshmukh.

Our Expert Take

Experts agree—sweet potatoes are an excellent carb choice when it comes to balancing blood sugars. “While we know that sweet potatoes can raise sugar levels as they are carbohydrates, the overall beneficial effect of the dietary fiber in sweet potatoes can help with glucose levels and improve blood sugar control,” says Pessah-Pollack. To prevent blood sugar spikes, be sure to leave the skin on and pair sweet potatoes with lean protein and nonstarchy veggies. This ensures you’ll get plenty of protein and fiber to slow carbohydrate absorption.