FASTING
Fasting Electrolytes: What You Need and When
Most fasting problems — headaches, fatigue, cramps, dizziness — aren't hunger. They're electrolyte deficiency. Here's how to prevent it.
Electrolytes are minerals that conduct electrical signals in your body. They regulate muscle contractions, nerve function, hydration, and blood pressure.
During fasting, electrolyte depletion is the number one cause of discomfort. Fix the electrolytes, and fasting becomes dramatically easier.
Why Electrolytes Deplete During Fasting
When you fast, insulin drops. Low insulin signals your kidneys to excrete sodium at a much higher rate than normal. This is called "natriuresis."
When sodium leaves, it pulls water with it (why you urinate more when fasting). It also pulls potassium and magnesium.
The cascade:
Fasting → Insulin drops → Kidneys excrete sodium → Water follows → Potassium and magnesium depleted → You feel terrible
This is why people who "can't fast" often can — once they address electrolytes.
The Three Key Electrolytes
Sodium
The most important and most rapidly depleted. Essential for nerve function, muscle contraction, and fluid balance.
Deficiency symptoms: Headache, fatigue, dizziness, brain fog, weakness, nausea
Daily target during fasting: 2000-3000mg (1-1.5 tsp salt)
Sources: Salt (any kind), bone broth
Potassium
Critical for heart function and muscle contraction. Harder to get than sodium. Often the most neglected.
Deficiency symptoms: Muscle cramps, heart palpitations, weakness, fatigue, irregular heartbeat
Daily target during fasting: 1000-3000mg
Sources: No Salt / Nu-Salt (potassium chloride), cream of tartar, Lite Salt
Magnesium
Involved in 300+ enzymatic reactions. Important for sleep, muscle relaxation, and nerve function.
Deficiency symptoms: Muscle cramps, insomnia, anxiety, twitching, irregular heartbeat
Daily target during fasting: 300-500mg
Sources: Magnesium citrate, glycinate, or malate. Epsom salt (magnesium sulfate) in drinks. Topical magnesium.
The Electrolyte Protocol
Daily targets during extended fasting:
- Sodium: 2000-3000mg
- Potassium: 1000-3000mg
- Magnesium: 300-500mg
These are ranges. Start on the lower end and increase if you have symptoms. Some people need more, especially if sweating or exercising.
How to Get Your Electrolytes
Option 1: Snake Juice (DIY)
Per 2 liters of water:
- • 1 tsp potassium chloride (No Salt)
- • 1/2 tsp Himalayan pink salt
- • 1 tsp baking soda
- • 1/2 tsp Epsom salt (magnesium sulfate)
Drink 2-3 liters throughout the day.
Option 2: Simple Method
- • 1/2 tsp salt in water, 2-3x per day
- • 1/4 tsp No Salt in water, 2x per day
- • 300-400mg magnesium glycinate capsule, once daily (evening)
Less mixing, similar results.
Option 3: Ready-Made Products
- • LMNT (great electrolyte ratio, flavored)
- • Redmond Re-Lyte
- • Drip Drop
- • Liquid IV (has some sugar — may impact strict fasting)
More expensive but convenient. Check sugar content.
When to Take Electrolytes
Morning
Start the day with electrolytes. You've been losing them overnight.
Throughout the day
Sip electrolyte water continuously. Don't take all at once — spread it out.
When symptoms appear
Headache? Try electrolytes before anything else. Cramps? Electrolytes. Fatigue? Electrolytes first.
Before bed
A small dose helps. Magnesium especially aids sleep. Don't overdo fluids or you'll be up all night.
Symptoms and What's Missing
Headache, fatigue, brain fog
Usually: Low sodium. Try 1/4-1/2 tsp salt in water.
Muscle cramps, especially legs
Usually: Low potassium or magnesium. Try both.
Heart palpitations
Usually: Low potassium. If severe or persistent, break the fast and see a doctor.
Dizziness when standing
Usually: Low sodium (causing low blood pressure). Salt water helps. Stand up slowly.
Insomnia, anxiety
Usually: Low magnesium. Take magnesium glycinate before bed.
Eye twitching, muscle twitching
Usually: Low magnesium.
Common Mistakes
Not taking any electrolytes
Many people fast "clean" and suffer needlessly. Electrolytes don't break a fast.
Only taking sodium
Potassium is harder to get and often more depleted. You need all three.
Taking too much at once
Can cause nausea and diarrhea. Spread intake throughout the day.
Using the wrong magnesium
Magnesium oxide is poorly absorbed. Use citrate, glycinate, or malate.
Drinking plain water excessively
Dilutes electrolytes further. If drinking lots of water, add electrolytes.
Do Electrolytes Break a Fast?
No.Pure electrolytes (sodium, potassium, magnesium) have no calories and don't affect insulin, ketosis, or autophagy.
What's safe during a strict fast:
- • Salt (any type)
- • No Salt / Lite Salt (potassium chloride)
- • Baking soda
- • Epsom salt (food-grade, in small amounts)
- • Pure magnesium supplements
- • Black coffee, plain tea
When You Need More Electrolytes
- • Hot weather — sweating increases losses
- • Exercise — especially if you're training while fasting
- • Longer fasts — 72+ hours requires more attention
- • Keto-adapted — keto and fasting both increase electrolyte needs
- • Coffee/tea — mild diuretics that increase excretion
Cautions
- • Kidney disease: Consult doctor before high potassium intake
- • Heart conditions or blood pressure meds: Consult doctor about sodium intake
- • Don't overdo it: More isn't better. Excess electrolytes cause problems too
- • If symptoms persist: Even with electrolytes, break the fast if you feel seriously unwell