Keto Electrolytes: Sodium, Potassium, Magnesium
Keto flu isn't a mystery. It's an electrolyte problem. When you cut carbs, your insulin drops, and your kidneys start dumping sodium and water fast. That's why you feel like garbage on day three. Headache, brain fog, cramps, zero energy. Most people white-knuckle through it. You don't have to.
Here's the protocol. You dose your electrolytes on purpose, every day, starting on day one. Nail sodium, potassium, and magnesium, and the "flu" mostly disappears. I've walked a lot of people through their first two weeks of keto, and this is the single biggest lever. Fix the minerals, fix the misery.
Why keto burns through your electrolytes
On a normal carb diet, high insulin tells your kidneys to hold onto sodium. Keto flips that switch off. Lower insulin means your body flushes sodium, and water follows it out the door.
Lose sodium and you throw potassium and magnesium off balance too. They all work together. That's the whole reason the cramps, fatigue, and headaches show up as a package deal. It's not one mineral. It's the trio.
So the fix is simple. Replace what you're losing. Let's put real numbers on it.
Sodium: 3,000 to 5,000 mg per day
This is the big one, and it's the one everyone's scared of. You've been told salt is the enemy your whole life. On keto, low sodium is what's actually making you feel awful.
Aim for 3,000 to 5,000 mg of sodium daily. That's roughly 1.5 to 2.5 teaspoons of salt spread across the day. If you're training hard or sweating a lot, lean toward the top of that range.
Food-first sources:
- Salt your food generously. Table salt, sea salt, doesn't matter much.
- Broth or bouillon. One cup can carry 800 to 1,200 mg of sodium.
- Pickles, olives, and cured meats.
- A pinch of salt in your water, sipped through the day.
Here's my go-to move. Cup of hot broth in the morning, salt everything you eat, and a pinch of salt in a big water bottle you finish before dinner. That alone gets most beginners into range.
Potassium: 3,000 to 4,000 mg per day
Potassium is the cramp fighter. Low potassium is why your calves seize up at 2 a.m. It works hand in hand with sodium, so if you're dosing salt but ignoring potassium, you're only halfway there.
Target 3,000 to 4,000 mg of potassium daily, and get most of it from food. This is the one I'd rather you eat than supplement, because potassium pills are capped low for safety reasons anyway.
Food-first sources:
- Avocado. One has around 700 mg. Easy win.
- Spinach and other leafy greens, cooked down.
- Salmon and other fish.
- Mushrooms.
- Salt substitutes like "Lite Salt," which are half potassium chloride. A little goes a long way.
Two avocados and a big serving of cooked spinach gets you a long way toward target without any pills. The math doesn't lie. Real food does most of the work here.
Magnesium: 300 to 400 mg per day
Magnesium is the recovery and sleep mineral. Low magnesium shows up as muscle twitches, poor sleep, and that wired-but-tired feeling. Most people are already low before they even start keto, and keto makes it worse.
Shoot for 300 to 400 mg of magnesium daily. Food helps, but this is the one where a supplement usually makes sense.
Food-first sources:
- Pumpkin seeds. A small handful is loaded.
- Dark leafy greens.
- Dark chocolate, 85 percent or higher, in small amounts.
- Nuts, especially almonds.
For a supplement, pick magnesium glycinate or citrate. Skip magnesium oxide. It's cheap, poorly absorbed, and it'll send you running to the bathroom. Take it in the evening and it doubles as a sleep aid.
How to actually dose this without overthinking it
Stop trying to hit every number to the milligram. You're aiming for a range, not a lab result. Here's the daily rhythm I give beginners.
- Morning: Cup of salted broth. Sets your sodium up early.
- Throughout the day: Salt your meals hard, drink a pinch-of-salt water bottle, eat an avocado and some greens.
- Evening: Magnesium glycinate before bed.
Your body will tell you when you're close. Headache fading, energy back, no more midnight cramps. That's the feedback loop. Feel off? Add more salt first. Nine times out of ten, that's the missing piece.
Powdered electrolyte packets work fine too if you don't want to think about it. Just check the label. A lot of them are underdosed on sodium, like 200 mg, which won't touch keto flu. You want ones that actually hit 500 to 1,000 mg of sodium per serving. LMNT sits at the top of that range with 1,000 mg of sodium per stick, plus potassium and magnesium, which is why it's the one I hand to people.
If you want your targets dialed to your own body weight and activity level instead of a generic range, run your numbers through the KetoDial calculator. It'll give you personal sodium, potassium, and fat targets so you're not guessing.
The one warning you can't skip
Free-dosing sodium and potassium is safe for most healthy people. It is not safe for everyone.
If you have kidney problems, you're on blood pressure medication, or you have any heart condition, do not load up on sodium or potassium on your own. Those minerals directly affect blood pressure and heart rhythm, and the wrong dose can be dangerous with those conditions. Talk to your doctor first and let them set your targets. This isn't optional. Period.
I'm not a doctor. I've coached people through keto and done it myself, so I know what works in practice. But I'm not your doctor. If you have health issues or take medications, check with someone qualified before changing how you eat or dosing electrolytes. Everything here is based on what works in the field and what research supports. Your mileage may vary.