Is Fiber One high in oxalate?
C
Moderately. Moderate, 13 mg per 2/3 cup
Range 13 to 13 mg across 1 study, 40 g serving
0 mg50 mg = a day60 mg+
Lower-oxalate swap: Corn flakes, grade A, about <1 mg per 1 1/2 cups.
Fiber One has a moderate amount of oxalate: about 13 mg per 2/3 cup, which is 26% of the 50 mg a day many stone clinics aim for.
Where this number comes from
Each row is one published measurement, converted to a 40 g serving (2/3 cup). The grade and the range use the rows prepared the way the serving is eaten, and take the middle. How the grades work.
| Per serving | Per 100 g | Preparation | Source |
|---|---|---|---|
| 13 mg | 32 mg | Ready to eat | Harvard T.H, 2023 |
By Oliver Silen · Data checked November 2, 2026 · Not medical advice