The best diet for kidney stones depends on the type of stone you have, but a few rules apply to almost everyone: drink enough water to produce at least 2.5 liters of urine daily, keep sodium under 2,300 mg a day, and eat plenty of fruits and vegetables. Beyond those basics, the specific foods you should eat more of or cut back on vary based on whether your stones are made of calcium oxalate, uric acid, or cystine.
Water Comes First
No dietary change matters as much as hydration. If you’ve had a kidney stone, aim for at least 2 to 3 liters (8 to 12 cups) of water per day. The goal is to keep urine dilute enough that minerals can’t concentrate and crystallize. Spreading your intake throughout the day matters more than drinking a large amount at once, and you’ll want to drink extra on hot days or after exercise. If your stones are the rarer cystine type, the target is even higher: roughly 4 liters a day to keep cystine concentration low enough to prevent new stones.
Don’t Cut Calcium, Pair It With Meals
This is the most counterintuitive piece of kidney stone nutrition. About 80% of kidney stones contain calcium, so it seems logical to eat less of it. But reducing dietary calcium actually raises your risk. The reason is straightforward: when you eat calcium alongside foods that contain oxalate, the calcium binds to oxalate in your gut before either gets absorbed. That bound pair passes harmlessly through your digestive tract instead of ending up in your kidneys.
When dietary calcium is too low, more free oxalate gets absorbed into your bloodstream and filtered through your kidneys, where it can combine with calcium to form stones. The American Urological Association recommends stone formers consume 1,000 to 1,200 mg of dietary calcium per day, ideally from food rather than supplements, and ideally spread across meals. Good sources include yogurt, milk, cheese, fortified orange juice, and canned fish with bones.
High-Oxalate Foods to Limit
If your stones are calcium oxalate, the most common type, reducing high-oxalate foods can make a real difference. Not all plant foods are equal here. Spinach is in a category of its own: a single half-cup of cooked spinach contains 755 mg of oxalate. That’s roughly six times more than almonds (122 mg per ounce) and ten times more than beets (76 mg per half-cup).
Other notably high-oxalate foods include:
- Rhubarb (541 mg per half-cup)
- Almonds (122 mg per ounce)
- Baked potato with skin (97 mg per medium potato)
- Beets (76 mg per half-cup)
- Cocoa powder (67 mg per 4 teaspoons)
- Cashews (49 mg per ounce)
- Raspberries (48 mg per cup)
You don’t need to eliminate every one of these foods. The strategy is to avoid the worst offenders (spinach, rhubarb) and eat moderate-oxalate foods alongside a calcium source so the oxalate gets bound in your gut. A handful of almonds with a piece of cheese, for example, is a smarter pairing than almonds alone.
Low-Oxalate Swaps That Work
Plenty of fruits and vegetables are virtually oxalate-free, so you’re not stuck eating bland food. Broccoli, cauliflower, cabbage, and cucumber all contain about 1 mg of oxalate per serving. For fruit, apples, blueberries, strawberries, peaches, grapes, and watermelon are all under 2 mg. If you’ve been eating spinach salads, switching to iceberg lettuce, kale, or mixed greens with broccoli gives you similar volume with a fraction of the oxalate.
Cut Sodium, Not Just Salt
Sodium is one of the biggest dietary drivers of calcium stones. When you eat excess sodium, your kidneys excrete more calcium into your urine, creating the raw material for stones. The target is under 2,300 mg per day, which is about one teaspoon of table salt. Most people get far more than that, and most of it comes from processed and restaurant food rather than the salt shaker.
Practical ways to lower sodium include cooking more meals at home, choosing low-sodium versions of canned soups and broths, rinsing canned beans before eating, and checking labels on bread, deli meat, and cheese, which are often surprisingly high. This single change reduces urinary calcium and helps prevent both calcium oxalate and calcium phosphate stones.
Animal Protein and Uric Acid Stones
Eating too much animal protein raises your risk of both calcium and uric acid stones through two mechanisms. It increases the acid load in your urine, which lowers urine pH and creates conditions where uric acid crystallizes. It also increases urinary calcium and decreases citrate, a natural stone inhibitor.
If you’ve had uric acid stones, reducing red meat, organ meats, shellfish, and other high-purine animal proteins is especially important. These foods break down into uric acid in your body. You don’t necessarily need to go vegetarian, but shifting the balance toward plant-based protein sources like lentils, beans, and tofu while keeping meat portions moderate (roughly the size of a deck of cards per meal) can meaningfully change your urine chemistry. The goal for uric acid stone formers is also to make urine less acidic, which means eating more fruits and vegetables and fewer acid-producing foods like meat, fish, and eggs.
Citrate-Rich Foods Protect Against Stones
Citrate is your body’s natural defense against stone formation. It binds to calcium in the urine and prevents crystals from growing. People with low urinary citrate are at higher risk for recurrence, and the simplest way to boost it is through diet.
Citrus fruits are the obvious source: lemons, oranges, and grapefruit all deliver citrate. Adding fresh lemon juice to your water throughout the day is one of the most commonly recommended habits for stone formers. But citrate isn’t limited to citrus. Bell peppers, tomatoes, carrots, kiwi, melons, pomegranates, and grapes are all good sources. More broadly, a diet rich in fruits and vegetables increases the overall alkali load of your diet, which raises urinary citrate and lowers acidity.
The DASH Diet as a Blueprint
If managing individual nutrients feels overwhelming, the DASH diet provides a simpler framework. Originally designed to lower blood pressure, it emphasizes fruits, vegetables, whole grains, legumes, nuts, and low-fat dairy while limiting red meat, sodium, and sweetened beverages. That profile happens to align closely with what kidney stone research supports.
A study of men with kidney stones found that high adherence to the DASH diet was significantly associated with lower rates of excess urinary calcium, low urinary citrate, and high urinary uric acid, three of the key risk factors for stone formation. In practical terms, following the DASH pattern addresses multiple stone-forming pathways at once: it keeps sodium low, calcium adequate, citrate high, and animal protein moderate, without requiring you to track oxalate milligrams for every meal.
Watch Out for Vitamin C Supplements
Your body converts excess vitamin C into oxalate, which is then filtered through your kidneys. The daily requirement is only 75 to 90 mg, but many supplements deliver 500 to 1,000 mg or more per dose. High-dose vitamin C supplements have been linked to increased kidney stone risk, particularly in men. If you have a history of calcium oxalate stones, getting your vitamin C from food (citrus fruits, bell peppers, strawberries) is safer than taking large-dose supplements.