Muscle cramps, headache and heart palpitations: electrolytes by symptom
Three symptoms of the first weeks on the method and one answer to all of them — sodium, potassium, magnesium. How to understand what is missing and what to do today.
Electrolytes and water
The most common reason women quit the method during the first week is not hunger. It is headaches, weakness, a racing heart when standing up, and nighttime cramps. All of this can be treated with salt and water within a day, but almost nobody knows this: they have heard “less salt” for years, and cannot bring themselves to do it. On a low-carb diet, the rule is reversed. This section explains why, how much you need, and where to get it. The main page for the topic is supplements and vitamins on the method.
3-5 g
salt per day
3.5-4.7 g
potassium per day
300-400
mg of magnesium
2-3 l
water
Why you need more salt on a low-carb diet
Insulin makes the kidneys retain sodium. When sugar and flour are removed, insulin drops—and the kidneys start excreting salt, along with water. During the first few days, 1-2 kilograms of water are lost, along with potassium and magnesium. This is the “keto flu”: headache, weakness, irritability, and brain fog. It is not a vitamin deficiency or that the “body does not accept it”—it is simply salt. The usual recommendation of “up to 5 g of salt” was written for people eating bread and sugar; on a low-carb diet, 3-5 g is the norm, not a maximum. Read more in salt on a low-carb diet; initial symptoms are covered in keto flu.
Potassium: from your plate, not pills
Potassium supports blood pressure, heart rhythm, and muscles. On a regular diet, its source is potatoes and bananas, which are not part of the method. Better substitutes include avocado (almost 1000 mg in one), spinach and greens, salmon, mushrooms, broccoli, and zucchini. Potassium supplements in pharmacies are limited to small doses for a reason—excess potassium is dangerous for the heart, so potassium should come from food, not capsules. See the detailed guide with a table at potassium from food.
Symptom — cause — what to do
| Symptom | What is lacking | What to do today |
|---|---|---|
| Headache, brain fog, weakness | salt, water | a glass of water with 1/4 tsp of salt; repeat after 2 hours |
| Nighttime calf cramps | magnesium, potassium | 300-400 mg of magnesium in the evening, avocado with dinner |
| Racing heart when standing up, darkening vision | salt, water | salt food to taste, water 2-3 l |
| Twitching eyelid, anxiety | magnesium | magnesium glycinate in the evening |
| Constipation | magnesium, water, salt | magnesium citrate, water, vegetables |
| Weakness during exercise | salt, water before and after | a pinch of salt in water 30 minutes beforehand |
Magnesium—the third electrolyte
It leaves the body along with sodium, and symptoms appear quietly: first you have trouble falling asleep, then you crave chocolate, then your calf cramps at night. Food provides some: greens, nuts, seeds, and 85% dark chocolate. A supplement covers the rest—300-400 mg in the evening, citrate for constipation, glycinate for poor sleep. Cramps go away within a week. Read the full guide on cramps and headaches; learn about the mineral itself in magnesium.
Water: how much and when
Two to three liters per day is the basic amount on a low-carb diet because the kidneys excrete more. But water without salt increases electrolyte loss: a glass with a pinch of salt and lemon works better than a liter of plain water. In hot weather and on training days, add one liter and more salt. During a fasting window, water with salt is essential: it is the only thing that distinguishes an easy pause from a difficult one. Read more about water in hot weather and during exercise; the basics are how much water to drink and salt and water during a pause.
Section rules
Salt—in food and water
You cannot drink it all in one spoonful. Salt food to taste, and add a pinch to a glass in the morning and after exercise.
Potassium from food
One avocado a day, greens with every meal, salmon twice a week. Tablets only as advised by a doctor.
Magnesium in the evening
300-400 mg of citrate or glycinate. Sleep and cramps will be the first to thank you.
Blood pressure—a monitor, not fear
With hypertension, discuss salt with a doctor, but for most people blood pressure falls on the method by itself.
Common mistakes
- Removing salt “for your health” and enduring a headache
- Drinking lots of plain water without salt
- Taking potassium tablets on advice from the internet
- Using magnesium oxide instead of citrate or glycinate
- Quitting the method on the third day without trying salt
Frequently asked questions
Which salt is best?
Any kind. Sea salt, Himalayan salt, or regular salt—all contain the same sodium. Iodized salt also provides iodine, making it a sensible choice.
Are ready-made electrolyte powders necessary?
They are convenient but not essential. Salt, avocado, and magnesium do the same thing for less money. Make sure the powder contains no sugar.
I have swelling—does that mean I’m consuming too much salt?
More often, the opposite is true: swelling on a low-carb diet is caused by a lack of potassium and protein, not salt. Check your water, potassium, and protein intake.
Articles in this section
Water in hot weather and during training: how much and with what
In summer and on training days, water and salt are lost through sweat twice as fast. How much to drink, what to add, and why plain water makes things worse.
Salt on a low-carbohydrate diet: how much, which kind and why more
The “less salt” rule was written for a diet with bread. On a low-carbohydrate diet, you need 3-5 g of salt a day — otherwise headaches, weakness and palpitations. How to salt food and what to do about blood pressure.
Potassium from food: avocado instead of banana
Potassium supports blood pressure, heart rhythm, and muscles. On the method, there are no bananas or potatoes — there are avocado, greens, salmon, and mushrooms. A table of sources and why not from pills.
Reviewed by Anastasia Zhukova, Fitness Trainer • Author of a Nutrition and Training System • Creator of an AI Personal Support Platform
A human has reviewed this material against the method and real client practice.