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Water Weight on Keto: Glycogen, Salt and the First-Week Drop

The fast weight drop in your first week of keto is mostly water, released as your body uses up stored carbs and sheds sodium, not fat.

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Why the first week drops so fast

Two things happen at once when you cut carbs:

  1. Your stored carbs run down. Your body keeps carbs as glycogen in the liver and muscles. Glycogen is stored with water, so using it up releases that water.
  2. Your body lets go of more sodium. Lower insulin changes how your kidneys handle salt, and water follows the salt out.

Both show up as a lower number on the scale and more trips to the bathroom. See why you pee so much on keto.

Glycogen: stored carbs hold water

His figure Source
Glycogen is stored with about twice its weight in water (about 2:1) video uDw65ERtsA0; video cTGYIFOTPl8
About 700 g glycogen plus 1,400 g water, about 4.4 lb video UygKGoP_BtA
About 3 lb of water in week one; 7–10 lb for heavier people video uDw65ERtsA0
Weight quoted in the first 14 days is mostly water video cTGYIFOTPl8

These are his figures. The evidence pages behind this guide do not cover the glycogen-to-water ratio, so treat the exact numbers as his estimates. The pattern, a quick drop that is mostly water, is the point.

Salt: lower insulin, more sodium out

Insulin tells the kidneys to hold on to sodium. In a classic study, an insulin infusion in healthy men, with blood sugar held steady, cut the amount of sodium, potassium and phosphate passed in urine (DeFronzo et al. 1975). When carbs drop and insulin falls, the reverse is expected: more sodium leaves, and water leaves with it.

The evidence on this for keto specifically is thin. PubMed searches found no highly cited trial that directly measures sodium loss on a ketogenic diet in adults. The mechanism comes mainly from fasting studies and insulin studies (see the electrolytes chapter).

KetoDick on this: he says that in ketosis you retain less salt, and that more water passing through flushes out more (video -dHjt_Bpruk). He also notes that once processed foods and starches are gone, much of the salt in a typical diet disappears too (video -dHjt_Bpruk).

This sodium loss is one reason for the headaches, cramps and tiredness people call keto flu. See electrolytes and sodium.

Why the first drop is not fat

The scale weighs everything: water, food in your gut, muscle and fat. A five-pound week one is not five pounds of fat.

A metabolic-ward study measured body fat directly. In 19 adults, carbohydrate restriction led to 53 ± 6 g a day of body-fat loss, against 89 ± 6 g a day with fat restriction (Hall et al. 2015). Scale weight and body fat are different measures, so a fast early drop on the scale is not evidence of fast fat loss.

KetoDick on this: he says not to post or judge weight in the first 30 days because early loss is water, and that body-fat weight is what matters (video cTGYIFOTPl8). See the weight-loss timeline.

Why water comes back

Water weight is quick to leave and quick to return.

What happens Why
A high-carb meal or day Glycogen refills and pulls water back in
A salty meal Extra sodium holds extra water for a day or two
A big meal late at night Food and water still in your gut

KetoDick on this: he says the week-one water returns almost immediately on a high-carb diet (video uDw65ERtsA0). He explains overnight gains as water and digestion, and posted his own five-pound overnight gain to show it is normal (video f9P8BPWHc4U). He also says salt balance and water retention move the scale (video -dHjt_Bpruk).

So a jump after an off-plan meal is mostly water, not fat regained. See gained weight overnight, what happens if you cheat and stall or fluctuation?.

How much salt: his number and the guidelines

His target and the official guidelines are far apart. Both are stated here.

Source Sodium per day
KetoDick: his own aim about 5,000 mg (video -dHjt_Bpruk)
National Academies (2019) Adequate intake 1,500 mg; reduce if above 2,300 mg (NASEM 2019)
American Heart Association No more than 2,300 mg; 1,500 mg "optimal" for most adults, with a note that it may not apply to people who lose a lot in sweat (AHA)

He bases his number on a study he describes as finding about 5,000 mg optimal for all-cause mortality (video -dHjt_Bpruk). The closest study on the evidence pages is PURE: in 101,945 people, sodium of 3–6 g a day, estimated from one morning urine sample, was associated with fewer deaths and heart events than higher or lower intakes (O'Donnell et al. 2014). That is an association, not a trial, and it remains debated.

His own routine is a chicken bouillon cube with a quarter teaspoon of potassium-chloride salt, three times a day (video -dHjt_Bpruk). The WHO suggests potassium-containing salt substitutes in place of regular salt, except for people at risk of high potassium (WHO). See potassium and magnesium and light salt.

What to do with this

  1. Expect the week-one drop and do not count it as fat.
  2. Skip the scale for the first 30 days, as he suggests (video uDw65ERtsA0). Then weigh weekly or every two weeks. See weighing in month one.
  3. Replace the salt you lose. Salted broth once or twice a day is his suggestion (video UygKGoP_BtA). See broth for keto flu.
  4. Drink to pale-yellow urine, not clear. See hydration.

Talk to your doctor first if:

Last verified: 2026-10-31