A major long-term study has found that eating French fries regularly raises the risk of developing type 2 diabetes, while other potato preparations do not show the same association. Researchers tracked more than 205,000 people over nearly four decades and published their findings in The BMJ. The results highlight how preparation methods and replacement foods affect health outcomes.
The observational study analyzed data from three large U.S. cohorts of health professionals collected between 1984 and 2021. Participants without diabetes at the start completed dietary questionnaires every four years. During follow-up, 22,299 people developed type 2 diabetes. Eating three servings of French fries per week was associated with a 20 percent higher rate of type 2 diabetes. The same amount of baked, boiled, or mashed potatoes showed no statistically significant link to increased risk. Overall potato intake was tied to a modest 5 percent rise. Replacing potatoes with whole grains lowered diabetes rates by up to 19 percent when French fries were swapped. Substituting potatoes with white rice instead raised the risk. Researchers noted the study cannot prove causation and called for more diverse populations in future work. An accompanying editorial stressed that potatoes should not be treated as a single category in dietary advice. It recommended prioritizing whole grains while noting that baked or boiled potatoes can fit into sustainable diets.
