What “keto flu” usually is
The first 3–7 days of strict low carb often bring headaches, fatigue, irritability, and muscle cramps. Much of this is sodium and water shift — insulin drops, kidneys excrete sodium, and volume depletes.
It is not an infection. It usually improves with electrolytes, sleep, and consistent low-carb meals — not with going back to high sugar.
Electrolyte fixes that help
Fasters use similar fixes — see electrolytes during fasting for overlap with assisted fasts.
- Sodium: bouillon, pickle juice, or salt on food — especially if you feel dizzy standing up
- Potassium: leafy greens, avocado, supplement only if provider approves
- Magnesium: glycinate or citrate at night for cramps and sleep
- Water: drink to thirst — chugging plain water without sodium can worsen cramps