Is watermelon good for kidney disease?
Watermelon is a lower-potassium choice at a normal portion: 1 cup, balls (5.4 oz, 154 g) has 172 mg of potassium, under the 200 mg per serving the National Kidney Foundation uses for high-potassium foods. The foundation lists it among lower-potassium foods: limit to 1 cup.
This page is for people with chronic kidney disease who have been told to watch potassium or phosphorus. Your kidney care team sets the limits that apply to you. These numbers help you fit a food into them.
Potassium, phosphorus and sodium by portion
| Portion | Potassium | NKF high-potassium line (200 mg) | Phosphorus | Sodium |
|---|---|---|---|---|
| 1 cup, balls (5.4 oz, 154 g) | 172 mg | Under 200 mg | 17 mg | 2 mg |
| 1 wedge (10.1 oz, 286 g) | 320 mg | High | 31 mg | 3 mg |
| 3.5 oz (100 g) | 112 mg | Under 200 mg | 11 mg | 1 mg |
USDA FoodData Central, Watermelon, raw. The 200 mg line is per serving, so the same food can be under it in a small portion and over it in a large one.
What the National Kidney Foundation and NIH say
- Level E National Kidney Foundation:
A food that is considered “high-potassium” generally has 200 mg or more potassium per serving.
National Kidney Foundation, Potassium and Your CKD Diet, accessed 2026-10-12 - Level E National Kidney Foundation:
Watermelon (limit to 1 cup)
(from the table: Foods that are LOWER in potassium (Less than 200 mg of potassium per serving)) National Kidney Foundation, Potassium and Your CKD Diet, accessed 2026-10-12
Word-for-word quotes. Level E means the position of an expert body. How we grade evidence.
How it compares with similar foods
| Food | Portion | Potassium | Phosphorus |
|---|---|---|---|
| Watermelon | 1 cup, balls (5.4 oz, 154 g) | 172 mg | 17 mg |
| Pomegranate | 1/2 cup arils (3.1 oz, 87 g) | 205 mg | 31 mg |
| Banana | 1 banana, peeled (4.1 oz, 115 g) | 375 mg | 25 mg |
| Soursop | 1 cup, pulp (7.9 oz, 225 g) | 626 mg | 61 mg |
Same USDA food group, each at its usual US portion. USDA FoodData Central.
The other side
Potassium limits apply to people whose care team has set one.
- Level C The standard advice to cut potassium in kidney disease rests on very low-quality evidence: restricting it moved blood potassium by 0.22 millimoles per liter and did not slow the disease. Morris et al., Journal of Renal Nutrition, 2020
- Level E There is no RDA for potassium because the data were insufficient to derive one, and no upper limit because high intakes do not cause hyperkalemia in adults with normal kidney function. NIH Office of Dietary Supplements, Health Professional Fact Sheet: Potassium
In practice
A cup of watermelon balls has 172 mg of potassium, under the 200 mg line. The National Kidney Foundation lists watermelon among lower-potassium foods and limits it to 1 cup.
A wedge is a much bigger portion. One wedge has 320 mg of potassium, well over the line, so measuring out a cup keeps you at the foundation's 1-cup limit.
Watermelon is also mostly water, about 91% by weight in the USDA data. If your care team has given you a fluid limit, ask whether to count it.
Written from the agency positions and data on this page, reviewed by the Bioma editorial system. How we verify.
Keep exploring
Sources
- National Kidney Foundation, Potassium and Your CKD Diet, https://www.kidney.org/kidney-topics/potassium-your-ckd-diet (accessed 2026-10-12)
- USDA FoodData Central, SR Legacy (2018): Watermelon, raw, FDC ID 167765
- USDA FoodData Central, SR Legacy (2018): Pomegranates, raw, FDC ID 169134
- USDA FoodData Central, Foundation Foods (release 2025-12-18): Bananas, ripe and slightly ripe, raw, FDC ID 1105314
- USDA FoodData Central, SR Legacy (2018): Soursop, raw, FDC ID 167761
- Evidence cards: each study above links to its source. Card review dates are listed in our methodology.
Sources checked 2026-10-12. Bioma Learn provides information, not medical advice.