There’s some mixed news for potato lovers.
A new Harvard study has found a connection between potato consumption and a higher risk of developing diabetes. But not all potatoes are created equal — some varieties and preparations are safer than others.
French Fries and Diabetes Risk
Lead author Seyed Mohammad Mousavi, a postdoctoral research fellow in Harvard’s Department of Nutrition, explained the shift in focus: “We’re shifting the conversation from, ‘Are potatoes good or bad?’ to a more nuanced — and useful — question: How are they prepared, and what might we eat instead?”
The study followed more than 205,000 people for over 30 years, tracking their eating habits. Results showed that consuming three servings of French fries each week increased the risk of diabetes by 20 percent. Other types of potatoes, such as baked or mashed, didn’t carry the same risk.
Healthy Swaps Can Lower Risk
Researchers also discovered that substituting potatoes with whole grains reduced type 2 diabetes risk by 4 percent. Swapping fries for whole grains offered even greater protection, lowering risk by 19 percent. Even replacing fries with refined grains like white bread showed some benefit.
“The public health message here is simple and powerful: Small changes in our daily diet can have an important impact on the risk of type 2 diabetes,” said corresponding author Walter Willett, professor of epidemiology and nutrition. “Limiting potatoes — especially limiting French fries — and choosing healthy, whole-grain sources of carbohydrate could help lower the risk of type 2 diabetes across the population.”
Other Studies Support the Findings
This isn’t the first time researchers have linked potatoes to diabetes risk. A 2022 Australian study revealed that people who ate the most potatoes had a 9 percent higher risk of diabetes compared to those who consumed the least.
Dr. Nicola Bondonno of Edith Cowan University’s Nutrition and Health Innovation Research Institute, who led that study, noted: “When we separated boiled potatoes from mashed potatoes, fries or [chips], boiled potatoes were no longer associated with a higher risk of diabetes. They had a null effect.”
She added, “It’s only fries and mashed potatoes [that increase risk], the latter likely because [they’re] usually made with butter, cream and the like.”
Potatoes Still Have Nutritional Benefits
Despite the risks tied to certain preparations, potatoes do offer health advantages. They’re rich in antioxidants such as flavonoids, carotenoids, and phenolic acids, which help fight cancer and heart disease. Potatoes also contain resistant starch, which nourishes gut bacteria, supports digestion, and helps regulate blood sugar.
In 2022, Polish researchers found that glycoalkaloids — natural compounds in potatoes, peppers, and goji berries — may have cancer-fighting effects.
“Potatoes are just fantastic,” said registered nutritionist Caroline Susie, a spokesperson for the Academy of Nutrition and Dietetics, in an interview with NBC News. “What happens is, unfortunately, we tend to screw them up by not eating the skin or frying or mixing them with everything under the sun, like sour cream and butter and bacon.”
