What to Not Eat During Stone? Dietary Advice for Kidney Stone Prevention

December 20, 2025 •

3 min read

According to the National Kidney Foundation, the percentage of people in the U.S. with kidney stones has increased from 4% in the late 1970s to 10% today, making dietary prevention more critical than ever. Understanding which foods can aggravate the condition is key to managing your health.

Quick Summary

This guide outlines the specific foods and drinks to limit or avoid based on kidney stone type, including high-oxalate items, excessive sodium, and animal protein, to help reduce recurrence.

Key Points

High-Oxalate Foods: Reduce or pair high-oxalate foods like spinach, almonds, and rhubarb with calcium-rich foods to prevent calcium oxalate stone formation.
Limited Sodium: Control sodium intake by avoiding processed foods and excess salt, as high sodium increases calcium excretion in urine, a major stone risk.
Moderate Animal Protein: Limit intake of red meat, poultry, and shellfish to help prevent both calcium and uric acid stones.
Hydration is Key: Drink plenty of water (2-3 quarts daily) to keep urine diluted and flush out stone-forming substances.
Avoid Sugary and High-Dose Vitamin C Supplements: Limit sweetened drinks and avoid high-dose vitamin C supplements, which can increase the risk of stones, especially for men.
Eat Dietary Calcium: Do not avoid calcium-rich foods. Adequate dietary calcium binds with oxalates in the gut, reducing oxalate absorption.

Understanding Kidney Stone Types

To effectively modify your diet, it is crucial to know the type of kidney stone you have, as different stones are impacted by different dietary factors. A urologist can perform a metabolic evaluation to determine your specific stone type. The most common types are calcium oxalate and uric acid stones, both of which are significantly influenced by diet and hydration.

High-Oxalate Foods to Limit

For those who form calcium oxalate stones, controlling oxalate intake is a primary concern. Oxalate is a natural compound found in many plants, and when it binds with calcium in the urine, it can form stones. However, it's not necessary to eliminate all high-oxalate foods, as some are quite healthy; instead, a dietitian might advise eating them in moderation and pairing them with calcium-rich foods.

Common high-oxalate foods include:

Spinach and rhubarb
Almonds, cashews, and peanuts
Beets and sweet potatoes
Chocolate and cocoa
Wheat bran and most berries
Black tea

Excess Sodium

A high-sodium diet is a major risk factor for kidney stones because it increases the amount of calcium your kidneys excrete into your urine. Excess urinary calcium can then bind with other substances to form crystals. Limiting your sodium intake to no more than 2,300 milligrams per day is recommended.

Sources of hidden sodium to avoid or limit:

Processed and fast foods
Canned soups and vegetables
Condiments like soy sauce, ketchup, and salad dressings
Deli and processed meats
Salted nuts and crackers
Adding excessive salt to food while cooking or at the table

High-Purine Foods for Uric Acid Stones

For individuals with uric acid stones, the focus shifts to reducing purine intake. Purines are natural chemical compounds found in food that the body breaks down into uric acid. High levels of uric acid in the urine can lead to stone formation.

High-purine foods to cut back on include:

Red meat (beef, pork, lamb) and organ meats (liver, kidneys)
Shellfish and some fish (anchovies, sardines)
Meat-based gravies
Beer and other alcoholic beverages, as they can increase uric acid levels

Sugary Drinks and Supplements

Staying well-hydrated is the single most important step for preventing kidney stones, as it dilutes the urine and prevents minerals from forming crystals. However, not all fluids are equal. Sugary drinks, particularly those with high-fructose corn syrup, can increase the risk of stone formation. Excessive caffeine and alcohol intake can also cause dehydration. It is also important to be cautious with supplements.

High-dose vitamin C supplements (over 1,000 mg/day) have been linked to an increased risk of calcium oxalate stones, especially in men. This is because the body can convert excess vitamin C into oxalate. Getting vitamin C from dietary sources is not a concern, but supplements should be avoided unless medically advised. Similarly, high-dose calcium supplements have been linked to increased stone risk, while obtaining calcium from food sources is protective.

Comparison of High-Oxalate and Safe Alternatives


Food Category	High-Oxalate Item (Limit)	Safe/Low-Oxalate Alternative (Enjoy)
Leafy Greens	Spinach, Swiss Chard	Kale, Cabbage, Lettuce
Nuts & Seeds	Almonds, Cashews, Peanuts	Sunflower Seeds, Macadamia Nuts
Fruits & Berries	Raspberries, Blackberries, Rhubarb	Citrus Fruits (Lemons, Oranges), Apples, Melon
Starchy Vegetables	Sweet Potatoes (with skin), Beets	White Potatoes (no skin), Carrots
Beverages	Black Tea, Cola, Sweetened Iced Tea	Water, Sugar-Free Lemonade, Herbal Tea

Conclusion

Navigating a diet for kidney stone prevention requires understanding which compounds contribute to different types of stones. The most effective strategies involve staying well-hydrated, moderating your intake of high-oxalate foods, limiting sodium and excess animal protein, and avoiding high-dose vitamin C supplements. Always consult with a healthcare provider or a dietitian to create a personalized plan tailored to your specific stone type and overall health needs.

For more information on preventing kidney stones, including dietary strategies, consult authoritative resources such as the National Kidney Foundation.

Frequently Asked Questions

A diet low in calcium can actually increase the risk of kidney stones. Dietary calcium binds with oxalate in the intestines, preventing it from being absorbed and passed to the kidneys where it can form stones.

High-dose vitamin C can be metabolized into oxalate, increasing urinary oxalate levels and the risk of forming calcium oxalate stones. This effect is particularly noted with supplements rather than food-based vitamin C.

High sodium intake increases the amount of calcium your kidneys excrete into the urine. This excess calcium can then combine with other minerals to form stones.

Not all animal protein is bad, but excessive amounts can be harmful. Limiting animal protein, especially red meat, is recommended as it can increase uric acid and calcium levels in urine.

It is best to avoid sugary drinks, such as sodas and fruit juices with added sugar, as well as excess coffee, black tea, and alcohol, which can cause dehydration and increase stone risk.

Yes, many processed and fast foods are high in sodium, phosphorus additives, and unhealthy fats, all of which contribute to kidney stone formation.

Good low-oxalate alternatives include fruits like melons, oranges, and apples, and vegetables such as cauliflower, cucumbers, and carrots.