The low-oxalate diet for kidney stones
By Oliver Silen · Updated November 2, 2026 · Not medical advice
A low-oxalate diet keeps the oxalate you eat under a daily target, usually 100 mg and sometimes 50, to lower the oxalate in your urine. It's for people who form calcium oxalate stones and have high urine oxalate [1].
The five changes that matter most
- Drink enough to make 2.5 liters of urine a day. It's the first line of the American Urological Association guideline for every stone type [3]. See water and lemon.
- Keep calcium at 1,000 to 1,200 mg a day, with meals. In a 5-year trial, a normal-calcium diet cut repeat stones to 12 of 60 men, against 23 of 60 on a low-calcium diet [4]. See calcium and oxalate.
- Drop the few very high foods. Spinach alone supplied over 40% of the oxalate in three large cohorts [2]. Of the 242 foods here, 20 grade E, more than a 50 mg day in one serving. Start with spinach (grade E, 316 mg per 1 cup raw), almonds (grade E, 90 mg per 1 oz (about 23 almonds)), rhubarb (grade E, 659 mg per 1/2 cup diced) and beets (grade D, 44 mg per 1/2 cup sliced, cooked).
- Cut salt. The guideline advises limiting sodium, since salt raises urine calcium [3], and the normal-calcium diet in the trial above was also low in salt and animal protein [4].
- Pick a target and count a day once. See 50 or 100 mg, then add up a normal day in the calculator.
What most people get wrong
- Cutting dairy. Low calcium raises urine oxalate. When a test diet dropped from 1,002 to 391 mg of calcium, urine oxalate rose 28% [5].
- Healthy swaps that backfire. Almond milk for milk, spinach smoothies, sweet potato for potato. See low-oxalate swaps.
- Trusting one list. Lists disagree because studies measured different varieties, preparations and lab methods. Every food page here shows each study's value, so you can see the range.
What to eat
Most fruit, dairy, meat, fish, white rice and many vegetables are low. See the oxalate food list, 3 sample days and common dishes, added up.