THURSDAY, Aug. 7, 2025 (HealthDay News) -- A higher intake of total potatoes, especially French fries, is associated with an increased risk for type 2 diabetes (T2D), according to a study published online Aug. 6 in The BMJ.Seyed Mohammad Mousavi, Ph.D., from the Harvard T.H. Chan School of Public Health in Boston, and colleagues examined the associations between total and individual potato intake and the risk for T2D. Individual data from the Nurses' Health Study (1984 to 2020), Nurses' Health Study II (1991 to 2021), and Health Professionals Follow-up Study (1986 to 2018) were included from 205,107 men and women free of diabetes, cardiovascular disease, or cancer at baseline.T2D was documented in 22,299 participants during 5,175,501 person-years of follow-up. The researchers found that higher intakes of total potatoes and French fries were associated with an increased risk for T2D after adjustment for updated body mass index and other diabetes-related risk factors. The rate for T2D increased by 5 and 20 percent for every increment of three servings weekly of total potato and French fries, respectively. In substitution analyses, replacing three servings weekly of potatoes with whole grains was estimated to lower T2D rates by 8, 4, and 19 percent for total potatoes; baked, boiled, or mashed potatoes; and French fries, respectively. In a meta-analysis of 13 cohorts with 587,081 participants and 43,471 T2D diagnoses, the pooled hazard ratio for T2D risk with each increment of three servings weekly of total potato and fried potatoes was 1.03 (95 percent confidence interval [CI], 1.02 to 1.05) and 1.16 (95 percent CI, 1.09 to 1.23), respectively."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," coauthor Walter C. Willett, M.D., Dr.P.H., from Brigham and Women's Hospital in Boston, said in a statement.Abstract/Full TextEditorial (subscription or payment may be required).Sign up for our weekly HealthDay newsletter