Good news, spuds lovers: New research found that, although regularly eating French fries increased the risk of type 2 diabetes, eating potatoes in other forms—such as mashed, baked, or boiled—did not affect type 2 diabetes risk.

The study, published in The BMJ, also revealed that replacing any form of potatoes with whole grains could lower the likelihood of developing the disease. This research isn’t the first to examine the effects of potatoes on diabetes risk. “We did this study because earlier research on potatoes and type 2 diabetes had mixed results—some studies showed a higher risk, others didn’t, and a few even suggested potatoes might be protective,” study author Seyed Mohammad Mousavi, PhD, a postdoctoral research fellow at Harvard University, told Health. “One big issue was that many of those studies didn’t look at how the potatoes were prepared—like fries versus boiled—or what people were eating instead,” he said.

Blood sugar control is no small concern for Americans. According to the Centers for Disease Control and Prevention, as of 2024, about 38 million people in the U.S.—or one in 10—had diabetes, of which 90 to 95% had type 2. Diet plays a major role in the development and management of type 2—and potatoes have long been dogged by a reputation for being bad for blood sugar. Because they’re high in carbohydrates and have a high glycemic index (i.e., how quickly they raise blood sugar), many people with type 2 diabetes avoid them.

As Mousavi noted, some previous studies have lumped all types of potatoes together for their effects on type 2 diabetes. Results from three prospective cohort studies in 2015, for example, concluded that greater consumption of potatoes in general (but especially French fries) was associated with a higher type 2 diabetes risk. A 2018 study had similar results, showing a connection between potato consumption and risk—again, more so for French fries.

Researchers wanted to take a more nuanced look at the connection between potato consumption and diabetes risk. Using data from three ongoing research programs, researchers followed over 200,000 health professionals for up to 36 years, regularly collecting detailed information about their diets and lifestyles. Dietary questionnaires showed the frequency with which they consumed French-fried, baked, boiled, or mashed potatoes. It also tracked their intake of whole grains.

By comparing this data with the number of new diagnoses of type 2 diabetes, the researchers determined that three servings weekly of French fries increased the risk of developing type 2 diabetes by 20%. Baked, boiled, and mashed potatoes, on the other hand, were not significantly associated with an elevated risk.