Boston, United States (Enmaeya News) — A new study published in The BMJ finds that eating French fries three times a week raises the risk of type 2 diabetes by 20%.

Researchers at Harvard T.H. Chan School of Public Health analyzed data from more than 205,000 U.S. adults over nearly 40 years. They discovered that how potatoes are prepared greatly affects health outcomes. Deep-fried French fries, high in unhealthy fats and calories, were linked to higher diabetes risk. But other potato forms — baked, boiled, or mashed — showed no such link.

Experts say the issue is not potatoes themselves, but the cooking method. Frying at high temperatures creates harmful compounds and adds calories, which can cause weight gain and insulin resistance. Healthier methods like baking, boiling, or air frying, especially with the skin on, keep important nutrients like fiber, vitamin C, and potassium.

The study also noted that swapping three weekly servings of French fries with whole grains such as quinoa or brown rice lowered diabetes risk by 8%. This suggests that both food type and preparation method matter for overall health.

In summary, potatoes can be part of a balanced diet, but it’s important to avoid frequent deep-fried versions. Choosing cooking methods that preserve nutrition may help reduce the risk of type 2 diabetes.