Acid load (PRAL) is a KidneyPal Pro feature that estimates how acid-forming or base-forming your food is. It’s information to discuss with your care team — it has no limit, no color, and it never changes your Kidney Score.
What the Number Means
PRAL stands for Potential Renal Acid Load. KidneyPal calculates it from five nutrients in a food: protein, phosphorus, potassium, magnesium, and calcium. Protein and phosphorus push the number up; potassium, magnesium, and calcium pull it down.
- A positive number (for example +12 mEq) means acid-forming. Meat, fish, cheese, eggs, and grains tend to be positive.
- A negative number (for example −4 mEq) means base-forming. Most fruit and vegetables are negative.
- The unit is mEq for the portion shown, and mEq per day for a daily value.
It is an estimate of the food, not of you. It is not a measure of blood acidity or urine pH, and it is not a kidney-safety score. KidneyPal doesn’t set a target for it — ask your nephrologist or renal dietitian whether dietary acid load matters in your situation and what to aim for.
Where You’ll See It
When acid load is on, an Acid load (PRAL) line appears:
- under the nutrient totals of a meal analysis, and in the review sheet while you edit foods (it updates as you change portions)
- in a meal summary (open it from a meal header in the diary)
- on a recipe, per serving, scaling with the servings you choose — and in a recipe you Export as PDF (one recipe or the whole cookbook), as a card for one serving
- on the Diary, as Acid load today, under your nutrient dashboard
- on the Progress tab, as the week’s daily average
- in the doctor report, as “Estimated dietary acid load (PRAL)”, averaged over the logged days in the period
- in a menu scan, in the I ordered this sheet’s estimate for the portion you pick — and on the diary entry once you add the dish
- in both spreadsheet exports — saved foods and the food log — as an Acid load PRAL (mEq) column after oxalate. Only complete values are filled in; a subtotal or an unknown value is left blank, so adding up the column never mixes in a partial number
Tap the line to see a short explanation.
Why You Might See a Dash or a “Subtotal”
The estimate needs all five nutrients. If a food is missing magnesium or calcium, KidneyPal won’t guess — it leaves that food out rather than treat the missing value as zero.
- ”—” with “Not enough data” — none of the foods could be calculated.
- “Subtotal · 5 of 6 foods” — the number covers only the foods that could be calculated, and tells you how many that is. It is never presented as a full total.
- On Progress and in the report, the daily average works the same way: it averages what could be calculated on each day, and when some foods were left out it says so — for example “Subtotal · 34 of 41 foods · 5 of 6 logged days”. When every food on every logged day is covered, it simply shows the number of days.
Things that can’t be included:
- Anything logged before acid load was added to the app. Those entries show ”—”. New entries are covered from the day you update.
- Manual entries without magnesium and calcium. When acid load is on, the manual entry form shows magnesium and calcium fields — fill in both (along with protein, phosphorus, and potassium) and the food counts.
- Menu dishes whose estimate is missing one of the five nutrients, and dishes from menus scanned before this update. Products you saved from the old Browse mode (removed in 4.46) without a full analysis aren’t included either.
- Your own recipes, unless every ingredient has a complete estimate. Ingredients added from saved foods or a label count when that food’s or label’s own acid load was complete. If you change a recipe’s nutrient by hand, its acid load disappears; it comes back only after you reset your manual values, tap Recalculate Nutrients, and save.
- Soup or “other” drinks added from the fluid shortcuts. Water, coffee, tea, juice, milk, and soda shortcuts do count.
- A food whose nutrients you cleared while editing. If you blank out one of the five values (protein, phosphorus, potassium, magnesium, or calcium), that food drops out of the estimate. For a food you entered manually you can bring it back by re-entering all five values (protein, phosphorus, potassium, magnesium and calcium) in Edit Log Entry — the app doesn’t trust a value it only remembers as 0.
Turning It On or Off
Go to Settings → Optional Nutrients and use the Acid load (PRAL) switch. It’s on by default for CKD Stage 3, 4, 5 and dialysis, and off for everyone else; your own choice always wins. There’s no limit to set — it’s information only. The one-time Pro setup has the same switch, under the nutrient cards (see Settings).
Acid load requires KidneyPal Pro. It’s also available in the web app.
Good to Know
- The formula is the published Remer & Manz method. It doesn’t account for salt, or for differences between protein sources.
- The nutrient values behind it are the same estimates the rest of the app uses, so treat the result as a guide, not a lab value.
- Acid load isn’t sent to Apple Health. It appears in the CSV exports only while the switch is on.
