Is watermelon good for kidney patients?

Low potassium — but it's mostly water

Watermelon is low in potassium (112 mg per 100g) — genuinely kidney-friendly in that sense. But it's ~92% water, so in dialysis patients every cup counts against the daily fluid allowance. Fluid-restricted patients must count watermelon as fluid, not 'free food.'

The Evidence

The good news: watermelon is low-potassium (112 mg/100g), making it a safe fruit choice at every CKD stage — a cup adds only ~170 mg potassium.

The dialysis catch: 1 cup of watermelon is ~140 mL of water. In fluid-restricted patients (typically 500-1,000 mL/day total), a large slice can eat a third of the daily allowance — which is why renal dietitians count it as fluid.

Practical: non-dialysis CKD — watermelon is a great fruit. Dialysis with fluid restriction — enjoy it, but count it and keep portions modest.