You’re on Day 4 of keto. You feel like you got hit by a truck. Headache, brain fog, muscle cramps, zero energy, and you can’t figure out why.
It’s not the diet. It’s not “keto flu” in the viral sense. It’s almost certainly electrolytes — and it’s the most fixable problem in all of keto.
Electrolyte imbalance causes 80%+ of the side effects people blame on “keto flu.” Fix your electrolytes and most side effects disappear within 24 hours.
Why Keto Wrecks Your Electrolytes
On a normal diet, carbs hold water and sodium in your body. Every gram of glycogen (stored carbs) holds 3-4 grams of water. When you cut carbs:
- Your body burns through glycogen in 1-2 days
- All that stored water gets released
- You pee out water and electrolytes together
- Your sodium, potassium, and magnesium levels drop
This is why you lose 5-8 pounds in your first week of keto — it’s mostly water weight. But with that water goes the electrolytes that keep your nerves, muscles, and brain functioning properly.
The 3 Electrolytes You Need
Sodium: 3,000-5,000mg per day
Sodium is the most important electrolyte on keto. Without enough, you get:
- Headaches
- Fatigue
- Dizziness when standing
- Muscle weakness
- Brain fog
- Low blood pressure
How to get it:
- Salt your food generously (1 tsp of salt = ~2,400mg sodium)
- Drink 1-2 cups of bouillon or broth per day
- Add salt to your water (1/2 tsp per liter)
- Eat salted nuts and pickles
Quick Tip
The “keto headache” that hits on Day 2-3 is almost always low sodium. Drink a cup of bouillon and it’ll be gone in 30 minutes. This is not a myth — try it.
Potassium: 1,000-3,500mg per day
Potassium works alongside sodium to regulate fluid balance and nerve function. Low potassium causes:
- Muscle cramps (especially leg cramps at night)
- Heart palpitations
- Weakness
- Constipation
How to get it from food:
| Food | Potassium per Serving |
|---|---|
| Avocado (1 medium) | 700mg |
| Spinach (1 cup cooked) | 840mg |
| Salmon (6 oz) | 780mg |
| Mushrooms (1 cup) | 420mg |
| Pork chop (6 oz) | 600mg |
| Zucchini (1 medium) | 500mg |
Do NOT take potassium supplements without consulting a doctor. Too much potassium from supplements can cause dangerous heart arrhythmias. Get it from food — it’s nearly impossible to overdose from food sources.
Magnesium: 300-400mg per day
Magnesium is the unsung hero of keto. It helps with:
- Sleep quality
- Muscle relaxation (prevents cramps)
- Bowel regularity
- Stress management
- Blood sugar regulation
Best forms:
- Magnesium glycinate — best for sleep and stress, gentle on stomach
- Magnesium citrate — best for constipation (also helps with sleep)
- Magnesium malate — best for energy and muscle function
Avoid magnesium oxide — it’s poorly absorbed and mostly wasted.
Food sources: pumpkin seeds, almonds, spinach, dark chocolate (85%+), avocado.
The Electrolyte Fix Protocol
If you’re feeling terrible on keto, follow this for 24 hours:
Morning
- 1 cup of bouillon or broth (2,000mg sodium)
- 1 avocado (700mg potassium, 40mg magnesium)
Lunch
- Salt your food with 1/2 tsp salt (1,200mg sodium)
- 2 cups of spinach in a salad (800mg potassium)
Afternoon
- 1/2 tsp salt in 1 liter of water (1,200mg sodium)
- Handful of almonds (80mg magnesium)
Evening
- Magnesium supplement: 200-400mg magnesium glycinate or citrate
- Dinner with salted food (another 1,200mg sodium)
Total: ~4,500mg sodium, 1,500mg potassium, 400mg magnesium. This hits the sweet spot for most people.
Signs Your Electrolytes Are Balanced
You’ll know your electrolytes are dialed in when:
- No headaches
- Steady energy all day
- No muscle cramps
- Clear thinking
- Normal bowel movements
- You don’t get dizzy when standing up quickly
- Sleep is restful
If you hit all of these, you’re golden. If not, adjust sodium first — it’s almost always the issue.
Do You Need Electrolyte Supplements?
The supplement industry wants you to think you need $30 electrolyte powders. You probably don’t.
You DO need:
- Salt (cheap, $2 for a pound)
- Magnesium supplement ($8-15 for a 3-month supply)
- Potassium from food (avocados and spinach are cheap)
You probably DON’T need:
- LMNT, Liquid IV, or other electrolyte powders (they’re fine but overpriced)
- Special “keto electrolyte” formulas
- Trace mineral drops (unless you have a specific deficiency)
The one exception: if you exercise heavily or live in a hot climate, you lose more electrolytes through sweat. An electrolyte powder can be convenient for those situations.
Key Takeaway
Fix your electrolytes first. 80% of “keto flu” is electrolyte deficiency, not the diet itself. Get 3,000-5,000mg sodium, 1,000-3,500mg potassium, and 300-400mg magnesium every day, and most side effects vanish.
Related Reading
- Keto Flu: Symptoms, Causes & 24-Hour Fix
- Keto Constipation: Why It Happens & 7 Fixes
- How to Get into Ketosis Fast
- Keto for Beginners: The Complete Starter Guide
- Not Losing Weight on Keto? 9 Reasons & Fixes
Recommended Kitchen Gear
For making electrolyte-rich bone broth at home, a good stockpot or Instant Pot is key. Check out our guides on KetoCookware for the best kitchen tools for keto cooking.