Fasted FASTED

Fasting Electrolyte Calculator

Calculate your exact sodium, potassium, and magnesium needs while fasting. Get a personalised daily schedule based on your body and symptoms.

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Electrolyte management is the difference between a comfortable fast and a miserable one. Most fasting side effects — headaches, cramps, fatigue, brain fog — are caused by electrolyte depletion rather than hunger itself.

When insulin drops during a fast, your kidneys flush sodium, which pulls potassium and magnesium with it. Replacing these minerals proactively keeps you feeling sharp and energised, making longer fasts far more sustainable and enjoyable.

Frequently Asked Questions

Can I take electrolytes while fasting without breaking my fast?
Yes. Pure electrolyte supplements containing sodium, potassium, and magnesium have zero calories and will not break your fast. Avoid electrolyte drinks that contain sugar, artificial sweeteners, or calories. Plain salt, potassium chloride, and magnesium citrate capsules are all safe during a fast.
Why do electrolytes drop during fasting?
When you fast, insulin levels drop significantly. Lower insulin causes your kidneys to excrete more sodium and water, which in turn pulls potassium and magnesium with it. This is why many people experience headaches, cramps, and fatigue during fasts — it is often electrolyte depletion, not hunger.
How much salt should I take while fasting?
For extended fasts over 18 hours, most adults need 2,000-3,000mg of sodium daily. Active individuals or those in hot climates may need up to 3,500mg. Start with a quarter teaspoon of salt in water in the morning and adjust based on how you feel.
What are the signs of electrolyte imbalance during fasting?
Common signs include headaches, muscle cramps, fatigue, dizziness, brain fog, heart palpitations, and nausea. If you experience any of these during a fast, try supplementing with electrolytes before ending your fast. Severe symptoms like irregular heartbeat or persistent vomiting mean you should break your fast and consult a doctor.
What are the best electrolyte supplements for fasting?
Look for supplements with no sugar, no artificial sweeteners, and no calories. Pure options include pink Himalayan salt or sea salt for sodium, potassium chloride (NoSalt or NuSalt brands), and magnesium citrate or glycinate capsules. Many people make their own "ketoade" by mixing these into water.

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Fasted tracks your water and electrolyte intake automatically

Log your electrolyte intake during fasts and get reminders when it is time for your next dose. The Fasted app keeps your hydration and minerals on track so you can fast safely.

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