Electrolytes: the missing piece
Most fasting headaches, fatigue and dizziness are sodium, not hunger.
Key points
- When insulin drops, your kidneys excrete more sodium and water. That's why you may feel light-headed, tired or get headaches — especially past 16 hours.
- On fasts over 16 hours, add about ½ teaspoon of salt (≈1 g sodium) to water through the day; on multi-day fasts, up to 1½–2 teaspoons total.
- Magnesium (200–400 mg glycinate or citrate at night) helps cramps and sleep. Potassium is best from food during your eating window — don't megadose supplements.
- Skip electrolyte drinks with sugar. Plain water, sparkling water, salt, and unsweetened tea or coffee are all fasting-safe.
- If you take blood-pressure, heart or kidney medication, ask your doctor before adding salt or potassium.
Kerndt et al., West J Med 1982 (fasting physiology); Cahill, Annu Rev Nutr 2006; Institute of Medicine dietary reference intakes.
Hunger Wave provides general educational information based on published research. It is not medical advice and does not replace a consultation with a healthcare professional. Stop fasting and seek help if you feel unwell.
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