Keto made easy

Chapter 7: Electrolytes, Hydration, Vitamins and Keto Flu

Summary: Keto makes your body pass more salt and water, so most early tiredness, headaches and cramps come from carb withdrawal, the adaptation gap, or low sodium, potassium or magnesium, and food plus salt fixes most of it.

On this page

The four electrolytes

Electrolytes are minerals that carry an electric charge in your body fluids. Four matter most for this chapter:

Electrolyte Main everyday source Why it comes up on keto
Sodium Table salt, broth, salted food Processed food and bread were most people's salt; they leave the menu
Potassium Vegetables, avocado, meat, "light salt" Potatoes and other common sources are high-carb
Magnesium Leafy greens, nuts, seeds Low-carb menus can fall short
Calcium Dairy, leafy greens Mostly covered if you eat dairy or greens

"Electrolytes" is a vague word. Naming the four makes it easier to see which one you are missing and where to get it.

KetoDick on this: He opens his electrolyte videos by naming exactly these four, and says sodium and potassium work as a ratio, not alone (video lbRPlGZ3Rvw; video -dHjt_Bpruk).

Why keto flushes more salt

Insulin tells your kidneys to hold on to sodium. When you eat very few carbs, your insulin level drops, and your kidneys let more sodium and water go. Doctors call this natriuresis.

The key study is old but well cited. In healthy men, raising insulin while holding blood sugar steady cut how much sodium, potassium and phosphate the kidneys passed (DeFronzo et al., 1975). Keto runs this in reverse: lower insulin, more sodium out.

One honest gap: no highly cited trial directly measures this salt loss in adults on a ketogenic diet. The case rests on fasting studies, insulin studies like DeFronzo's, and reviews (per this guide's electrolytes evidence review).

Two more things push sodium down at the same time:

  1. Bread, chips, crackers and packaged food leave your diet, and they carried most of your salt.
  2. The water you drop in week one leaves with sodium in it. See water weight.

For how insulin fits the bigger fat-loss picture, see insulin and fat loss.

How much of each: the reference numbers

Official bodies do not agree on sodium. They agree more on potassium and magnesium.

Mineral Reference Daily amount for adults
Sodium WHO 2012 Under 2,000 mg
Sodium NASEM 2019 Adequate intake 1,500 mg; cut back if above 2,300 mg
Sodium American Heart Association No more than 2,300 mg; ideal 1,500 mg for most adults
Potassium WHO 2012 At least 3,510 mg from food
Potassium NASEM 2019 Adequate intake 2,600 mg (women), 3,400 mg (men)
Magnesium NIH Office of Dietary Supplements 310–320 mg (women), 400–420 mg (men); supplement limit 350 mg

The sodium debate is real. The large PURE study (n = 101,945) linked 3–6 g of sodium a day with fewer deaths and heart events than higher or lower intakes, a "J-curve" (O'Donnell et al., 2014). It measured sodium from one morning urine sample and is observational. Trials do show salt cuts lower blood pressure, more in people who already have high blood pressure (Graudal et al., 2017).

Details, food lists and the fights over these numbers are on the sodium and potassium and magnesium pages.

KetoDick on this: He aims for about 5,000 mg of sodium a day, citing a mortality study, and gets much of it from chicken bouillon three times a day (video -dHjt_Bpruk). That is well above the WHO, NASEM and AHA numbers, and inside the PURE range. Both are stated here so you can weigh them with your doctor.

Keto flu is several problems with one name

"Keto flu" is not influenza. It is not an infection and you cannot catch it. It is a nickname for how some people feel in the first week or two.

The symptoms people report usually come from one of three places:

Cause Typical signs What usually helps
Carb and sugar withdrawal Cravings, irritability, low mood Time; tapering carbs if you prefer a slower start
The adaptation gap Low energy, poor sleep in weeks 1–2 Time; eat enough; see fat adaptation
Low electrolytes Headaches, cramps, weakness Salt, broth, greens

An analysis of online posts found that reported keto flu symptoms bunched up in the first weeks and were mostly described as short-lived (Bostock et al., 2020). That study read posts; it did not test people.

KetoDick on this: He dislikes the name. He calls most of it carb and sugar withdrawal, says the label lumps the adaptation gap and electrolyte cramps together, and flags the withdrawal view as more his opinion than science (video 9r2Y74AnjUQ).

Full breakdown: Keto flu: what it is, what causes it, what helps.

Water: check your urine, not a glass count

A fixed number of glasses a day does not fit everyone. A simpler check is the colour of your urine:

Some medicines and vitamins change urine colour, so the check does not work for everyone. The evidence pages behind this guide do not include a study on urine colour; treat it as a rough everyday check.

More water is not always better on keto. Each trip to the bathroom also passes sodium and potassium.

KetoDick on this: He calls "drink lots of water and take lots of electrolytes" a "hamster wheel" (from the video) and uses urine colour as his one test (video RGfWR5jQNDQ).

Full page: How much water on keto?

Multivitamins: what the trials show

Two different questions get mixed up here.

  1. Can a restricted diet leave gaps? Yes. In the A TO Z trial, women on Atkins shifted toward low intake of thiamine, folate, vitamin C, iron and magnesium at 8 weeks; the other diets had other gaps (Gardner et al., 2010).
  2. Does a multivitamin prevent disease? The US Preventive Services Task Force says the evidence is not enough to judge (USPSTF 2022).

The Dietary Guidelines for Americans 2020–2025 put food first: needs met mainly from food and drink, supplements where needs are hard to meet otherwise. Details: Do you need a multivitamin on keto?

KetoDick on this: In 2018 he suggests a common over-the-counter multivitamin with magnesium and calcium, saying he endorses no brand (video UygKGoP_BtA); in 2017 he lists a multivitamin among his electrolyte sources as a way to "cover your bases" (auto-caption) (video lbRPlGZ3Rvw).

When to involve your doctor

Salt from food and broth is low-risk for most healthy adults. These cases need your doctor first:

The full list is on who should talk to a doctor.

Pages in this chapter

  1. Sodium on keto: how much salt and why
  2. Potassium and magnesium on keto: food first, pills via your doctor
  3. Keto flu: what it is, what causes it, what helps
  4. How much water on keto? Use your urine, not a glass count
  5. Do you need a multivitamin on keto?

Previous: Fat · Next: Testing for ketosis

Last verified: 2026-10-31