Electrolyte Imbalances on Keto (and How to Prevent Them)

If we could deliver one message to every keto beginner, it would be this: electrolytes matter more than macros in the first two weeks. Nearly every complaint about keto — headaches, cramps, fatigue, brain fog, irritability, palpitations — is downstream of low sodium, potassium, or magnesium.

Why keto drains electrolytes

Low insulin causes the kidneys to excrete more sodium. As sodium leaves, potassium follows. Magnesium is often already low in the general population and losses accelerate. Unless you actively replace all three, you'll feel awful — regardless of how 'clean' your keto diet is.

Daily targets

• Sodium: 3,000–5,000 mg. From: salt on food, broth, olives, pickle juice, electrolyte drinks.
• Potassium: 3,000–4,000 mg. From: avocado, spinach, salmon, mushrooms, potassium chloride ('lite salt').
• Magnesium: 400 mg. From: pumpkin seeds, dark chocolate (90%+), almonds, magnesium glycinate supplements.

The problem with 'just eating spinach'

Spinach is potassium-rich, but you'd need to eat 3 lb to hit your daily target. Most people need to combine food sources with a light supplement — especially for magnesium.

The best magnesium form

Magnesium glycinate is well-absorbed and gentle on the stomach. Magnesium citrate works but can loosen stools. Magnesium oxide is cheap but poorly absorbed — avoid it.

Warning signs of electrolyte imbalance

• Sudden fatigue disproportionate to activity
• Muscle cramps, especially in the calves at night
• Heart palpitations or lightheadedness on standing
• Persistent headache not relieved by water
• Constipation (often magnesium)
• Brain fog or inability to focus

When to see a doctor

If you take blood pressure medication, diuretics, or have kidney disease, do not supplement electrolytes without physician guidance. Levels can shift quickly on keto and interact with medications.