Urine volume targets, citrate-rich beverage recommendations, and dietary adjustments for stone prevention.
Stones form when urine becomes too concentrated with calcium, oxalate, and uric acid. The single most important preventive factor is fluid — specifically, urine output of at least 2.5 liters per day. Because some fluid is lost through sweat and breathing, you need to drink more than 2.5 liters to produce that much urine.
Citrate (from lemon or lime juice) binds to calcium in urine, preventing crystal formation. A half cup of fresh lemon juice per day can significantly raise urinary citrate. Dietary calcium actually reduces stone risk by binding oxalate in the gut — but calcium supplements can increase risk.
Tip: Check your urine color. Pale straw is the goal. Dark yellow means you're concentrated. Amber means you're in the danger zone. Keep a 1-liter bottle and finish one by breakfast, one by lunch, one by dinner, and another half by bedtime.