KetoKeto flu: what it is and how to handle it
The headache, tiredness and light-headedness of the first week, and how to fix it.
In the first days to two weeks, some people feel headache, tiredness, dizziness or light-headedness, nausea, or muscle cramps. This is the 'keto flu'. It happens because as your body switches over, your kidneys flush out water and salts (sodium, potassium, magnesium).
What helps:
- Add salt. A cup of broth, or a quarter to half teaspoon of salt in water.
- Hit your electrolyte targets (Ketofiti shows them).
- Drink enough water, but always pair it with salt.
- Eat enough fat so you are not hungry and low on energy.
It usually passes within days to two weeks. If you vomit repeatedly, cannot keep fluids down, or feel confused with fast breathing and fruity breath, stop and seek medical care.
Sources
- Symptoms during initiation of a ketogenic diet: a scoping review (PubMed, 2025)
- Nutritional supplements to induce ketosis and reduce keto-induction symptoms: a narrative review (PubMed)
- Ketogenic diets and physical performance: sodium and water loss during ketosis (Nutrition & Metabolism)
- Adult Diabetic Ketoacidosis: warning signs. StatPearls, NCBI Bookshelf
General information, not medical advice. Always consult a qualified health professional before changing how you eat, especially if you are pregnant, breastfeeding, diabetic or taking medication.