Is Watermelon Acidic or Alkaline?
Watermelon (fresh) is alkaline: Negative PRAL: alkalizing after digestion.
Classification
Watermelon is alkaline at −1.7, but milder than honeydew or cantaloupe: it contains even more water, so the minerals are spread thinner per 100 g. On the other hand, you can easily eat 300 g, which adds about −5. At 35 kcal per 100 g, it works as both a drink and a dessert in summer.
In the Fruit category, watermelon (fresh) ranks #72 of 80, sorted from alkaline to acid-forming. More alkaline options include Physalis (cape gooseberry) (−1.7), Sour cherry (−1.8), Apple sauce, unsweetened (−1.9). More acid-forming are Apple sauce (−1.6), Cranberry (−1.4), Wild blueberry (−1.3).
Acidic or alkaline: PRAL, not pH
On this site, acidic and alkaline refer to the PRAL (potential renal acid load). It estimates what a food leaves behind once it has been digested: a positive value is acid-forming, a negative value is alkalizing. That is different from the pH of the food itself: a lemon tastes sour, yet its PRAL is −4.0, so it is alkalizing. Your diet does not change your blood pH. It does change how much acid your kidneys have to deal with.
Goes well with
Frequently Asked Questions
Is watermelon acidic?
It depends on what you mean by acidic. The pH describes the food itself, for example how sour it tastes. The PRAL describes what it leaves behind after digestion: Watermelon (fresh) has a PRAL of −1.7 per 100 g, so it counts as alkaline in your daily acid-base balance.
How much watermelon do I need for a noticeable effect?
One piece or a handful (120 g) of watermelon adds −2.0 to your daily balance. For comparison: an egg is around +5.4, a slice of cheese around +6. So one serving of watermelon roughly offsets one of them.
Why is watermelon alkaline even though it tastes sour?
The PRAL depends on the minerals left over after digestion, not on taste or pH. Watermelon provides more potassium, magnesium and calcium than phosphorus and protein, so the balance is negative (−1.7).
Watermelon logged, balance checked.
Basentracker adds up every meal automatically and shows whether your day is in the alkaline range. The same values as on this page, all 977 foods, photo scan, recipes.
Free for Android · iPhone coming soon
Compare all Fruit: Fruit table. Common questions are answered in Acidic or Alkaline?, and the PRAL calculator adds up a whole meal.
Source: Basentracker food database (PRAL according to Remer & Manz, calculated from protein, phosphorus, potassium, magnesium and calcium per 100 g). This information does not replace medical advice.