Are Frozen French Fries Acidic or Alkaline?
Frozen french fries (prepared) are strongly alkaline: Negative PRAL: alkalizing after digestion.
Classification
This surprises many people: prepared frozen french fries are clearly alkaline at −6.8. The potato keeps its potassium and loses water when baked or fried, which strengthens the value per 100 g. The PRAL says nothing about fat and salt, and the fries still have 203 kcal per 100 g. A 150 g serving adds about −10 and offsets roughly half of a breaded schnitzel.
In the Meals & Fast Food category, frozen french fries (prepared) rank #4 of 118, sorted from alkaline to acid-forming. More alkaline options include Guacamole (−8.7), French fries, fast-food (−11.4), Fried potatoes (with onions) (−12.0). More acid-forming are Potato salad (vinaigrette) (−4.6), Potato gratin (−4.0), Potato salad (with mayonnaise) (−3.8).
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
Are frozen french fries 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: Frozen french fries (prepared) have a PRAL of −6.8 per 100 g, so they count as strongly alkaline in your daily acid-base balance.
How much frozen french fries do I need for a noticeable effect?
A meal (300 g) of frozen french fries adds −20.3 to your daily balance. For comparison: an egg is around +5.4, a slice of cheese around +6. So one serving of frozen french fries roughly offsets one of them.
Why are frozen french fries alkaline even though they are not typical alkaline foods?
The PRAL depends on the minerals left over after digestion, not on taste or pH. Frozen french fries provide more potassium, magnesium and calcium than phosphorus and protein, so the balance is negative (−6.8).
Frozen French Fries 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.
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Compare all Meals & Fast Food: Meals & Fast Food 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.