Keto made easy

Why Do I Pee So Much on Keto?

Quick answer: Two things happen at once in the first days. Your insulin drops, and lower insulin tells your kidneys to let go of more sodium, which takes water with it. And you burn through your stored glycogen, which is packed with roughly twice its weight in water (video uDw65ERtsA0). That water has to go somewhere. It's normal, it settles down, and it's the main reason salt matters so much on keto.

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Reason one: insulin and your kidneys

Insulin isn't only about blood sugar. It also tells your kidneys to hold on to sodium. A classic study in healthy men raised insulin while keeping blood glucose steady, and their kidneys excreted less sodium, potassium and phosphate (DeFronzo 1975).

Flip that around. When you cut carbs, insulin comes down, and the "hold on to sodium" signal gets weaker. Where sodium goes, water follows. So you pee more, and the salt goes with it.

KetoDick's plain-language version: in ketosis you have less ability to retain salts (from the video -dHjt_Bpruk). More on insulin's other jobs in Does Insulin Make You Fat?.

Reason two: glycogen comes with water

Your body stores carbohydrate as glycogen in your liver and muscles. KetoDick's rule of thumb is that glycogen is stored with water at about a 2 to 1 ratio, two parts water to one part glycogen (video uDw65ERtsA0).

When you stop eating carbs, your body uses that glycogen up in the first days. As it goes, the water stored with it is released. That's a big part of week one's scale drop, and a big part of the bathroom trips (videos uDw65ERtsA0, NUJNFG6lLWw).

This is also why that weight comes back fast if you go back to high-carb eating: refill the glycogen and the water comes back with it (video uDw65ERtsA0). See Gained Weight Overnight on Keto?.

The back-of-envelope water maths

Here are his numbers, worked through.

He also says he usually quotes men's figures though most of his audience is women, and to scale them down about 25 to 35% (video 1vyxuWlxT5M). Take 30% off and you land a little over 3 lb, which matches the "about three pounds" of week-one water he describes for a typical person. He says heavier people may see 7 to 10 lb in week one (video uDw65ERtsA0).

None of that is fat. It's water you were carrying around with your carb stores, and it leaves the way water leaves.

Reason three: you're probably drinking more

Everybody on keto gets told to hydrate. KetoDick notes that people on keto drink a little more than people who aren't, so more water passes through and flushes more salt (video -dHjt_Bpruk).

That's fine up to a point. Past that point it's the "hamster wheel" he warns about: more water, more trips, more electrolytes out, more electrolytes needed (from the video RGfWR5jQNDQ). That's its own post: Can You Drink Too Much Water on Keto?.

So what you do

  1. Expect it. The first week or so is the peak, and it's a sign the carbs are actually down.
  2. Salt your food. Most of your old salt was hiding in bread, chips and sauces, and that's gone now (video -dHjt_Bpruk).
  3. Add broth if you need it. He uses bouillon in hot water, with a little potassium-chloride salt stirred in (video -dHjt_Bpruk). See Broth for Keto Flu.
  4. Check your colour, not your count. Pale yellow is the target; clear and constant means ease off the water (video RGfWR5jQNDQ). How-to: Urine Colour and Hydration.
  5. Don't celebrate the week-one number. He says to skip the scale for the first 30 days (video uDw65ERtsA0).

What the research says

The glycogen-to-water ratio is his figure from the videos; it isn't one the evidence pages here measured.

KetoDick's take

He ties early weight loss on keto mostly to water: flushing glycogen and retaining less salt (video NUJNFG6lLWw). His weight-loss schedule calls week one "water weight" and tells you it comes back quickly if you go back to a high-carb diet (video uDw65ERtsA0).

He gives three reasons salt runs short on keto, and peeing more is two of them: the salt in starches and processed food disappears, ketosis retains less salt, and more water passing through flushes more (video -dHjt_Bpruk). Salt balance also drives the water retention that moves your scale up and down later on (video -dHjt_Bpruk).

When to involve your doctor

Key takeaways