What “keto flu” usually is
“Keto flu” is an informal label, not a diagnosis. Headache, fatigue, nausea, dizziness, irritability, and cramps after a diet change have many possible causes.
Do not assume symptoms prove an electrolyte deficit or that they must be endured. Severe, persistent, or worsening symptoms need medical assessment.
Safer responses to symptoms
Fasters use the same toolkit — electrolytes during fasting covers assisted vs water-only details.
- Pause the dietary change if you feel unwell
- Eat regular, nutritionally adequate meals and drink normally
- Do not self-treat dizziness with salt or potassium
- Ask a clinician or pharmacist before using electrolyte supplements
- Seek urgent care for chest pain, fainting, severe confusion, or breathing difficulty
Day-by-day expectations
If you take blood-pressure medication, tell your prescriber before making a major diet or sodium change. Do not alter the medicine yourself.
- There is no reliable day-by-day symptom schedule
- Symptoms that persist should not be normalized as adaptation
- A macro calculator cannot identify the cause of symptoms