Are French Fries Acidic or Alkaline?
Alkaline. Fast-food French fries have a PRAL of −11.4 per 100 g and oven-baked frozen fries −6.8, thanks to the potato, but that says nothing about fat and salt.
Why french fries are alkaline
Potatoes provide a lot of potassium and little protein, which makes them one of the few filling side dishes with a negative PRAL. Deep-frying drives water out of the potato, so the potassium becomes more concentrated per 100 g. Boiled potatoes come in at −6.5, fast-food French fries at −11.4. Croquettes are almost neutral at −0.4 because the breading adds protein and phosphorus that push the other way.
The PRAL doesn't account for frying fat or salt. Per 100 kcal, boiled potatoes come in at −8.6, fast-food fries at −4.8 and frozen fries at −3.3. If you want a large alkaline surplus for few calories, eat your potatoes boiled or baked.
Acidic or alkaline: PRAL, not pH
The PRAL (potential renal acid load) estimates what a food leaves behind after digestion. It is not the pH of the food itself: a lemon tastes sour, yet its PRAL is −4.0. If you are asking whether french fries are acidic because of heartburn or reflux, that is a question of pH and your stomach, which the PRAL does not measure; talk to your doctor about it.
French Fries in different forms: raw, cooked, processed
How the PRAL changes with state and product. All values per 100 g or 100 ml.
| Food | PRAL |
|---|---|
| French fries, fast-food (fried) | −11.4 |
| Frozen french fries (prepared) | −6.8 |
| Fried potatoes (with onions) (fried) | −12.0 |
| Frozen potato croquettes (raw) | −0.4 |
| Potato (boiled) | −6.5 |
| Potato, with skin (baked) | −8.7 |
Goes well with
Frequently Asked Questions
Are frozen fries less alkaline than fast-food fries?
Yes. Oven-baked frozen fries come in at −6.8 and fast-food fries at −11.4 per 100 g. Both are clearly alkaline, but per calorie they are far weaker than boiled potatoes.
Are French fries healthy if they're alkaline?
No. The PRAL only measures the acid-base balance. Frying fat, salt and calories aren't part of it. A serving of fast-food fries (150 g) has about 360 kcal.
French Fries and everything else on your plate: calculated automatically.
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More meals & fast food compared
All meals & fast food with their PRAL: Meals & Fast Food table. Back to the overview Acidic or Alkaline?, or put together a meal in the PRAL calculator.
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.