Why do I feel tired or get headaches on carnivore or keto?

Nine times out of ten it's electrolytes, usually low sodium. Cutting carbs makes your kidneys excrete more sodium and water, so if you don't replace it you get the fatigue, headaches and brain fog people call 'keto flu'. Salting your food more is often the fix.

How much salt should I eat on a low-carb diet?

Many low-carb sources suggest more than the usual guideline — often around 4 to 6 grams of sodium a day, adjusted to how you feel — because you excrete more on low insulin. If you have high blood pressure or kidney issues, check with your doctor before increasing salt.

Do I need to supplement magnesium on carnivore?

Often, yes. Magnesium is the electrolyte hardest to get enough of from meat alone, and low levels cause cramps, poor sleep and muscle twitches. Many people top up with a supplement of a few hundred milligrams a day in a well-absorbed form, while getting sodium and potassium mostly from food.

Can electrolytes break a fast?

Plain electrolytes without calories — salt, or a zero-calorie magnesium or potassium supplement — won't meaningfully break a fast, and often make fasting easier by preventing the fatigue and headaches that come from mineral loss. Avoid electrolyte products with added sugars or sweeteners that carry calories.

How to track electrolytes on a carnivore or keto diet

On a carnivore or keto diet, the three electrolytes that matter most are sodium, potassium and magnesium — and low-carb eating depletes them faster than a normal diet does. Getting them right is what separates people who feel great on carnivore from those fighting fatigue, cramps and headaches. Here's why it happens and how to stay ahead of it.

This is general information, not medical advice. If you take medication or have kidney, heart or blood-pressure conditions, talk to your doctor before making big changes to your electrolyte intake.

Why low-carb depletes electrolytes

The mechanism is straightforward. When you cut carbs, your insulin levels drop. Lower insulin tells your kidneys to excrete more sodium and water — which is why the first week of carnivore or keto usually comes with a quick "whoosh" of water weight. That's not fat; it's fluid, and it takes electrolytes with it.

So the depletion isn't a flaw in the diet — it's a predictable side effect of running on lower insulin. The catch is that most "electrolyte problems" people blame on carnivore are really just the diet flushing minerals faster while they eat as if nothing changed. Replace what you're losing and most symptoms disappear.

The three that matter

Sodium is the big one, and it runs opposite to the mainstream "eat less salt" message. On low-carb you're excreting more of it, so many people actually need more salt, not less. Under-salting is the single most common cause of low-carb fatigue, headaches and that "keto flu" feeling. Salt your food to taste — though if you have high blood pressure or kidney issues, clear this with your doctor first.

Potassium works alongside sodium, and low levels show up as muscle weakness, cramps and fatigue. On carnivore you get a fair amount from meat itself, especially red meat, but it's worth being aware of.

Magnesium is the one people most often run low on, and it tends to cause cramps (particularly at night), poor sleep and twitchy muscles. It's harder to get enough from a meat-only diet alone, which is why it's the electrolyte most people end up supplementing.

Roughly how much?

Individual needs vary a lot with sweat, activity, climate and how strict you are, so treat these as commonly cited starting points rather than prescriptions:

Sodium: many low-carb sources suggest noticeably more than the standard guideline — often in the region of 4–6 grams of sodium a day (roughly 10–15 g of actual salt), adjusted to how you feel.
Potassium: a few grams a day, much of which can come from meat and other whole foods.
Magnesium: a few hundred milligrams a day, commonly topped up with a supplement.

Again, if you take medication or have a kidney, heart or blood-pressure condition, don't freelance these numbers — get a professional to weigh in on your situation.

Food first, then supplement

You don't have to reach for pills first. On carnivore, a lot of this is covered by:

Salt — added generously to food, or a pinch in water.
Red meat — a solid source of potassium and magnesium.
Organ meats, especially liver — genuinely mineral-dense if you can stomach them.
Bone broth — an easy way to get sodium and fluid together, which is why it's a carnivore staple.

Supplement the gaps rather than replacing food — magnesium is the one most people genuinely need to add; sodium is usually just a matter of salting more.

How to track it

You don't need lab-grade precision here — you need to know roughly whether you're getting enough, and to connect symptoms to intake. The practical approach:

Log your intake so you can see, over a week, whether you're anywhere near those ranges. This is exactly the kind of thing Hewett Health tracks alongside your macros, so sodium, potassium and magnesium aren't invisible.
Watch for the tell-tale symptoms — fatigue, headache, cramps, poor sleep — and treat them as signals to check your electrolytes before assuming something's wrong with the diet itself.
Adjust by feel. Electrolyte needs shift with heat, training and sweat. Had a hard session or a hot day? You need more. The goal is steady energy and no cramps, not hitting an exact number.

Get sodium, potassium and magnesium roughly right and the vast majority of "carnivore made me feel awful" stories never happen. It's the most common fixable mistake on the diet.