Golden, crispy, and irresistible-French fries are one of the world’s favorite comfort foods. But while they satisfy our cravings, new scientific findings suggest they could also be contributing to a growing health problem. A major study published in The BMJ on August 6, 2025, has linked regular consumption of French fries with a 20% higher risk of developing type 2 diabetes.

The study at a glance

The research analyzed data from more than 205,000 participants in the Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-up Study. Over nearly 30 years, participants recorded detailed information about their diets, including how often they ate French fries, whole grains, or other potato preparations. During the follow-up period, 22,299 people were diagnosed with type 2 diabetes.

Small changes, big Impact

The study’s findings highlight how even minor dietary adjustments can significantly influence health outcomes. According to Dr. Walter Willett, professor of epidemiology and nutrition at Harvard University and co-author of the study:

“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.”

Limiting French fries and choosing whole-grain alternatives could lower diabetes risk across the population by up to 19%.

Potatoes vs. French Fries: The Real Issue

The research also explored whether the problem lies with potatoes in general or French fries in particular. Seyed Mohammad Mousavi, the study’s lead author, explained:

“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 results showed that preparation is key. Unlike French fries, potatoes prepared by baking, boiling, or mashing were not linked to type 2 diabetes risk.

Why cooking method matters

Just three servings of French fries per week were associated with a 20% rise in diabetes risk. In contrast, replacing French fries with healthier options—especially whole grains like brown rice, oats, or whole-grain bread—was linked to a significant drop in risk. Even substituting French fries with refined grains showed a small benefit.

These findings were confirmed through additional analyses involving over half a million people, reinforcing the conclusion: French fries increase risk, while whole grains reduce it.

Rethinking carbohydrates

The research underscores an important lesson-not all carbs are created equal. For policymakers and individuals alike, the focus should move away from broad food categories and toward preparation methods and substitutions. As Willett summarized:

“Not all carbs, or even all potatoes, are created equal, and that distinction is crucial when it comes to shaping effective dietary guidelines.”