Macrovelo supports keto as one program among several. This guide is for people who already chose keto and feel rough in week one. It is not medical advice, and it is not a reason to stay on keto if the approach is a poor fit for you.
If you have just started a ketogenic diet and feel wiped out, you are not alone. The "keto flu" is a common, usually temporary cluster of symptoms as your body uses less glucose and more fat for fuel. Some people barely notice it. Others feel it for a few days.
What often causes the keto flu?
When you cut carbs sharply, insulin typically falls and the kidneys release more water and sodium. Electrolytes such as sodium, potassium, and magnesium can drop with that water.
That depletion is what many people describe as keto flu:
- Headaches and brain fog
- Fatigue and lethargy
- Muscle cramps
- Nausea and dizziness
- Irritability
If symptoms are severe, last more than a short stretch, or you have a medical condition, talk to a clinician. Do not treat this article as a diagnosis.
Practical steps people use
You do not have to "push through" dehydration. Replenish fluids and minerals, and make sure you are actually eating enough.
1. Prioritize electrolytes
Many people feel better with more sodium in the first week: bone broth, a pinch of salt in water, or a zero-sugar electrolyte mix. Typical keto guidance often lands around several grams of sodium per day — your needs depend on blood pressure, meds, and how much you sweat. Check with a clinician if you are unsure.
2. Drink more water
Because you may shed water quickly at the start, sip consistently through the day rather than chugging once and forgetting.
3. Eat enough fat and protein
Sometimes early fatigue is simply not eating enough. Fat is a large part of a keto plate. Add olive oil, avocado, or butter if meals feel sparse — without turning every meal into a "more is better" contest.
Need a structured keto week?
Navigating the first few weeks is easier when meals are already mapped. Take the Macrovelo quiz if you want meals, workouts, and logging for a keto week. If keto is not sitting well, the same product can plan a different diet — the point is a plan you can follow, not ketosis at any cost.