Diet to prevent kidney stones
Prevent kidney stones through diet. Hydration, oxalates and tips based on stone type.
Calorie calculation examples by profile
Sedentary woman, 45 years old, 143 lbs
Active woman, 45 years old, 143 lbs
Sedentary man, 45 years old, 176 lbs
Active man, 45 years old, 176 lbs
Understanding kidney stones
Kidney stones form when certain substances crystallize in urine. The most common are calcium oxalate stones (70-80%), followed by uric acid stones (10-15%), calcium phosphate, and struvite. Diet plays a major role in prevention, but stone type determines specific recommendations.
Hydration: cornerstone of prevention
The most important measure is drinking enough to produce 2 to 2.5 liters of urine daily. This means drinking about 2.5 to 3 liters of fluids. Water is the best choice. Diluted urine reduces the concentration of stone-forming substances. Spread hydration throughout the day, including before bedtime.
Oxalates: moderate, don't eliminate
For calcium oxalate stones (most common), moderating high-oxalate foods can help: spinach, rhubarb, beets, nuts, chocolate, black tea. But don't eliminate these foods completely. Consume them with calcium sources that bind oxalates in the intestine, reducing their absorption.
Calcium: paradoxically protective
Contrary to popular belief, reducing dietary calcium increases stone risk. Calcium binds oxalates in the intestine and prevents their absorption. Maintain an intake of 1000-1200 mg/day through food. However, avoid calcium supplements taken outside of meals.
Important
Never go below 1200 kcal/day (women) or 1500 kcal/day (men) without medical supervision. Too aggressive a deficit can be dangerous for your health and counterproductive for weight loss.
Dietary guide for kidney stone prevention
Important: These tips mainly concern preventing recurrence. If you’ve had a stone, have its composition analyzed to precisely adapt your diet. Consult a urologist or nephrologist for personalized recommendations.
Diet can significantly reduce the risk of kidney stone recurrence.
Different types of stones
| Type | Frequency | Main causes | Dietary strategy |
|---|---|---|---|
| Calcium oxalate | 70-80% | Hyperoxaluria, hypercalciuria | Moderate oxalates, maintain calcium |
| Uric acid | 10-15% | Excess animal protein, low urine pH | Reduce meats, alkalinize |
| Calcium phosphate | 5-10% | High urine pH | Moderate acidification |
| Struvite | 5% | Urinary infections | Treat infection |
Universal rules (all stone types)
1. Hydration: the absolute priority
- Goal: produce 2 to 2.5 L urine/day
- Consumption: 2.5 to 3 L fluids/day
- Distribution: throughout the day
- Verification: clear to slightly yellow urine
| Time | Recommended amount |
|---|---|
| Upon waking | 1-2 glasses |
| Morning | 500 ml (17 oz) |
| Noon | 500 ml (17 oz) |
| Afternoon | 500 ml (17 oz) |
| Evening | 500 ml (17 oz) |
| Before bed | 1 glass |
2. Reduce sodium
Salt increases urinary calcium excretion:
- Goal: < 2300 mg/day (ideally < 1500 mg)
- Avoid: ready meals, deli meats, salty cheeses
- Prefer: home cooking, herbs and spices
3. Animal protein in moderation
Excess animal protein promotes several stone types:
- Amount: 0.8-1 g/kg/day
- Limit: red meats, organ meats
- Vary: alternate with plant proteins
For calcium oxalate stones
Moderate oxalates (don’t eliminate)
| Very high (limit) | High (moderate) | Low (free) |
|---|---|---|
| Spinach | Beets | Lettuce |
| Rhubarb | Sweet potatoes | Cucumber |
| Pecans | Chocolate | Broccoli |
| Almonds | Black tea | Cabbage |
| Peanuts | Raspberries | Apples |
Tip: pair oxalates with calcium
Consuming calcium-rich foods AT THE SAME MEAL as oxalate-rich foods reduces oxalate absorption.
Example: spinach + yogurt sauce
Maintain good calcium intake
- Goal: 1000-1200 mg/day
- Sources: dairy products, sardines, green vegetables
- Avoid: calcium supplements outside meals
Citrate: protective
- Lemon, orange, grapefruit
- Daily lemon water (1-2 squeezed lemons/day)
For uric acid stones
Reduce purines
| Avoid | Limit | Free |
|---|---|---|
| Organ meats | Red meats | Eggs |
| Anchovies, sardines | Poultry | Dairy products |
| Beer | Seafood | Grains |
| Meat broths | Legumes | Fruits and vegetables |
Alkalinize urine
- Fruits and vegetables (alkalinizing effect)
- Bicarbonate water (per medical advice)
- Limit animal proteins
Sample day (calcium oxalate)
Breakfast
- Yogurt with fresh fruits
- Whole grain bread, butter
- Green tea or coffee
- 2 glasses of water
Lunch
- Grilled chicken (4 oz)
- Rice with vegetables (not spinach)
- Green salad, olive oil, lemon
- Fruit
- Water (2 glasses)
Snack
- Cheese and crackers
- Lemon water
Dinner
- Fish (3.5 oz)
- Pasta with broccoli
- Cucumber salad
- Plain yogurt
- Water (2 glasses)
Evening
- 1 glass of water before bed
Mistakes to avoid
- Reducing calcium: opposite effect, increases risk
- Eliminating all oxalates: unnecessary and restrictive
- Forgetting hydration: the most important measure
- Taking excess vitamin C supplements (converted to oxalate)
- Ignoring stone type: recommendations vary
Why Voical can help you
With Voical, you can track your daily hydration and ensure you meet your goals. The app also helps you monitor your sodium and animal protein intake, key factors in kidney stone prevention.