Which salt for a water fast?

Pink, Celtic, and ordinary table salt

In 2020, Flavia Fayet-Moore, Cinthya Wibisono, and colleagues measured 31 pink salts from shops in Australia and compared them with one iodized white table salt. They published the results in the journal Foods. Per kilogram, the pink salts averaged about 395 grams of sodium and the iodized white salt about 428 grams, which is the same neighborhood. From those averages, a teaspoon of the pink salt, which they took as 5 grams, works out to about 2 grams of sodium, about 12 milligrams of potassium, 13 milligrams of magnesium, and 13 milligrams of calcium. The paper says the teaspoon did not add a meaningful amount of those other minerals. Sodium was the exception: that one teaspoon is about a whole day's sodium on its own, against the limit of less than 2 grams a day that the paper cites. They also say you would need more than 30 grams, about six teaspoons, before the other minerals added up, and that much salt is already far too much sodium.

The white salt in that comparison was iodized, meaning iodine had been added on purpose. Pink salt is not that product. One of the 31, the only sample from Peru, was over the lead limit the paper used. The Himalayan-labelled salts in the sample were under that limit. A pink label is still not a reason to pick that salt for a fast.

Celtic salt was not in that study. It is still culinary salt. A damp salt holds water, so a spoon of it is not the same weight as a spoon of dry table salt. A mine, a coast, or a color does not turn the pinch into a mineral supplement. Plain table salt does the sodium job.

How much goes in the bottle

We don't give a grams-per-bottle number, because the safe amount depends on the person. For someone with kidney or heart disease, or on blood-pressure medicine, extra salt can be the problem. What people usually do is small: a pinch of salt in water, sipped through the day rather than loaded into each bottle. A dull headache, a cramp, or lightheadedness is the usual sign people are low, and a reason to sit down and drink water. If a pinch is already your habit, it stays a pinch. It is not a signal to keep pouring, and it is not a treatment.

Potassium powder and magnesium powder are a different decision from that pinch. They have doses, and they interact with kidneys and with some blood-pressure medicines. Water and minerals past a day is the note for that stretch. It does not list scoops either.

A week is not a salt question

Kidney disease, heart disease, a heart-rhythm condition, blood-pressure medicine, and water pills change whether extra salt is safe. Those situations are listed in Who should be careful with fasting. If the stretch you mean is a week, read If you already mean many days and talk with a clinician before you start. The timer can count the hours. It cannot clear the week.

Dizziness, confusion, fainting, chest pain, or a heartbeat you cannot explain means stop. Eat, if you can do that safely, and get help. More salt does not fix that list. The signs are in When to stop a fast.

The first meals after many days are still part of the stretch. They are a medical topic, not a plate you copy from a comment. Eating again after many days is that landing. Breaking a fast gently is the shorter sketch, for a daily window and a shorter stretch.