The single most effective way to prevent kidney stones is to drink more water. Increasing your fluid intake throughout the day can cut your risk of recurrence by at least half. Beyond hydration, a handful of specific dietary changes targeting sodium, calcium, oxalate, and sugar make a meaningful difference. Most people who’ve had one kidney stone will form another within 10 years without changes, but that trajectory is far from inevitable.
Drink Enough Water to Dilute Your Urine
If you’ve had a kidney stone before, aim for at least 2 liters (about 8 cups) of water per day, and ideally 3 liters (12 cups). The goal is to produce enough urine that the minerals dissolved in it never get concentrated enough to crystallize. A simple way to gauge whether you’re drinking enough: your urine should be pale yellow or nearly clear throughout the day.
Spacing your intake matters as much as the total volume. Drinking a large amount in the morning and nothing for the rest of the day still leaves hours when your urine is concentrated. Keep a water bottle nearby and sip consistently, including before bed. Overnight is when urine sits in the kidneys longest, so a glass of water before sleep and another if you wake up during the night can help.
Cut Back on Sodium
Salt is one of the most underappreciated drivers of kidney stones. When you eat more sodium, your kidneys excrete more calcium into your urine, and that extra calcium is the raw material for the most common type of stone. In a controlled trial, people who followed a low-salt diet lowered their urinary calcium from about 361 mg per day to 271 mg per day. Nearly twice as many people on the low-salt diet brought their calcium levels back into the normal range compared with those who didn’t change their salt intake.
Most dietary sodium comes from processed and restaurant food, not the salt shaker. Check nutrition labels and look for products with 5% or less of the daily value for sodium per serving. Cooking at home with fresh ingredients is one of the most practical ways to stay under 2,300 mg of sodium per day, which is the general recommended limit.
Don’t Avoid Calcium, Eat It With Meals
This is the advice that surprises most people. Since the most common kidney stones are made of calcium oxalate, it seems logical to eat less calcium. But the opposite is true. Dietary calcium binds to oxalate in your gut before either one reaches the kidneys. Without enough calcium at mealtime, more oxalate gets absorbed into your bloodstream and filtered through your kidneys, where it can combine with calcium and form stones.
Aim for 1,000 to 1,200 mg of calcium per day, which works out to roughly two or three servings of dairy. The key detail is timing: eat your calcium-rich foods with meals, especially meals that contain higher-oxalate ingredients. A glass of milk with a spinach salad, for example, lets the calcium and oxalate meet in your digestive tract rather than in your kidneys.
Manage High-Oxalate Foods
Oxalate is a natural compound found in many healthy foods. You don’t need to eliminate all of them, but if you’ve had calcium oxalate stones, it helps to be strategic about the biggest contributors. The foods highest in oxalate include:
- Spinach
- Rhubarb
- Nuts and nut products
- Peanuts (technically a legume, but very high in oxalate)
- Wheat bran
You don’t necessarily have to avoid these entirely. Eating smaller portions and pairing them with a calcium source at the same meal reduces the amount of oxalate that reaches your kidneys. If you eat a lot of these foods daily, though, cutting back is worth considering.
Add Citrus to Your Routine
Citrate is a natural stone inhibitor. It binds to calcium in the urine and prevents crystals from forming and growing. One of the easiest ways to increase your citrate levels is through lemon juice. Drinking half a cup of lemon juice concentrate diluted in water each day, or the juice of two lemons, has been shown to raise urinary citrate and likely reduce stone risk. Limes and oranges also contain citric acid, though lemon juice is the most studied option.
This is a particularly useful strategy because it doubles as hydration. Squeezing lemon into a large bottle of water gives you flavor and a dose of citrate throughout the day.
Reduce Added Sugar
A sugar-heavy diet is a significant and often overlooked risk factor. In a study of more than 28,000 adults tracked over 11 years, those who consumed 25% or more of their daily calories from added sugars had an 88% higher risk of developing kidney stones compared with people who kept their added sugar below 5% of daily calories. Sugar-sweetened beverages like soda and energy drinks are among the largest sources, but cookies, cakes, sweetened cereals, and other processed snacks also contribute.
Replacing soda with water or citrus-infused water addresses two risk factors at once: it cuts sugar intake and increases fluid volume.
Watch Your Animal Protein Intake
Diets high in animal protein, particularly red meat, poultry, and seafood, increase the acid load in your body. Your kidneys respond by excreting more calcium and less citrate, both of which raise stone risk. High animal protein also contributes to uric acid stones by making urine more acidic. You don’t need to go vegetarian, but if you eat large portions of meat at every meal, scaling back and replacing some servings with plant-based protein can help shift your urine chemistry in the right direction.
Medications for Repeat Stone Formers
If dietary changes alone aren’t enough to prevent recurrences, your doctor may prescribe medication based on the type of stone you form. The two most commonly used classes are thiazide-type diuretics, which reduce the amount of calcium your kidneys release into the urine, and potassium citrate, which raises citrate levels and makes urine less acidic. These are considered equally effective tools for prevention.
Both medications work best when combined with the dietary strategies above. A prescription without lifestyle changes is less effective, and vice versa. If you’ve had multiple stones, a 24-hour urine collection test can identify exactly which minerals are elevated in your urine, letting your doctor tailor both diet and medication recommendations to your specific chemistry rather than relying on general advice.
Putting It Together
Prevention works best as a combination of small, consistent habits rather than one dramatic change. The highest-impact steps, roughly in order of how much evidence supports them: drink at least 2 to 3 liters of water daily, reduce sodium from processed foods, eat adequate calcium with meals, limit high-oxalate foods if you’ve had calcium oxalate stones, add lemon juice to your water, and cut back on added sugar and excess animal protein. None of these changes require extreme restriction, and together they can reduce your recurrence risk by half or more.