Why do I feel terrible in the first week of keto?

That's the 'keto flu' — headaches, fatigue, cramps, brain fog. It's largely caused by your body flushing out water and electrolytes when you cut carbs. Staying on top of sodium, magnesium, and potassium can prevent most of it.

Do I need more salt on keto?

Yes, actually. On a standard diet you're told to limit salt, but on keto your body needs more of it because you're excreting more. If you're lightheaded or headachy, adding salt to your food or drinking salty broth is usually the first fix.

What magnesium should I take on keto?

Look for well-absorbed forms like magnesium glycinate or citrate. I take mine at night — it genuinely helps with sleep and muscle cramps. Avoid magnesium oxide, which isn't absorbed as well.

The Electrolytes I Actually Take on Keto (and Why the Keto Flu Is Optional)

I have a confession: I used to think “electrolytes” was just a fancy word for Gatorade. Then I started keto, hit the wall in week two, and learned the hard way that the keto flu is mostly an electrolyte problem.

Here’s the honest version of what I actually take, why it matters, and the “do your own research” caveat that applies to everything on this blog.

Why Electrolytes Matter on Keto

When you cut carbs, your body flushes out water — and with it, the electrolytes that keep your muscles, nerves, and heart working. That’s a huge part of why people feel awful in the first week: headaches, fatigue, cramps, brain fog.

The good news? The keto flu is largely optional. If you stay on top of electrolytes, you can skip most of the misery.

The Three That Matter

Sodium (the big one)

This is the one people get most wrong. On a standard diet, you’re told to limit salt. On keto, you actually need more of it, because you’re excreting more. I add salt to my food liberally and drink salty broth or an electrolyte mix when I feel off. If you’re lightheaded or headachy, sodium is usually the first thing to fix.

Magnesium

Magnesium helps with sleep, muscle cramps, and that restless feeling. I take a magnesium supplement at night — it genuinely helps me sleep better. Look for forms like magnesium glycinate or citrate, which are well-absorbed.

Potassium

Potassium supports heart and muscle function. I get it from foods like avocado, spinach, and salmon — all keto staples. I don’t take a potassium supplement (that’s one to be careful with), I just make sure I’m eating potassium-rich foods.

What I Actually Do

Morning: I salt my food and drink plenty of water.
When I feel off: I drink an electrolyte mix or a cup of salty broth.
Night: magnesium supplement before bed.
Foods: avocado, spinach, salmon, and nuts are in regular rotation.

The Honest Caveat

Here’s the part I have to say: I’m not a doctor, and this is not medical advice. Everyone’s needs are different, and some people have conditions (kidney issues, heart conditions, high blood pressure) where messing with electrolytes is genuinely dangerous. Please do your own research, and talk to your doctor before adding supplements — especially if you’re on medication or managing a health condition.

But for most people doing keto, the answer to “why do I feel terrible?” is usually: you need more salt. Start there.

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