Water fasting ketosis is where the fat burn heaven begins

Written by , Last updated: October 21, 2017

In this guide, you will learn everything you need to know about water fasting ketosis.

I'll explain how water fasting can help you reach your absolute highest possible fat burn rates, which is easily the single biggest benefit of ketosis.

Water fasting ketosis is where the fat burn heaven begins

You'll also see the science on how long it actually takes before you can enter ketosis during a water fast. You'll also learn about one of the most dangerous problems of water fasting ketosis.

I'll also tell you why it is a very good idea to avoid one of the most common mistakes people make once they already reach ketosis during a water fast.

Now that you know what you're getting yourself into, here's a quick overview of everything that's covered in this guide:

The single biggest benefit of water fasting ketosis

Simply put, ketosis is a state where you get to enjoy your absolutely highest possible fat burn rates.

If you're on your regular diet, your body can draw energy from a couple of different sources (so not just from your body fat reserves). Those other, non-fat energy sources are the main reason why your fat burn rates stay on the low end, even if you start eating less food.

But during a water fast, because you're eating no food at all, those other energy sources in your body will be completely wiped out after a while. Once that happens, your body will enter full ketosis, and in that state of full ketosis, your body will have no choice but to rely almost exclusively on your body fat reserves.

With no other energy sources available, ketosis will trigger some pretty amazing fat burn rates in your body.

Water fasting is one of the fastest ways to reach that state of super high fat burn. And a lot of people do a water fast just for this reason.

There's only one problem with reaching ketosis through water fasting.

PRO TIP: A different kind of a fast, called a muscle sparing fast can help you reach even higher fat burn rates than water fasting can. Go here to find out more.

How long does it take to enter ketosis on a water fast?

According to one water fasting study[1], it can take up to 3 days before your body can reach full ketosis during a water fast.

Because, even if you stop eating food completely, your body will still have to burn away your non-fat energy reserves first. As long as any of those are around, you won't be able to reach full ketosis.

I call these non-fat energy reserves "fat burn blockers", because as long as there's even a trace of them left, your body will never be able to fully focus on burning away just that stored body fat.

In other words, if you do a water fast and decide not to do anything to speed things along, you probably won't get to reach your highest possible fat burn rates in full ketosis before day 4.

PRO TIP: There are 3 things you can do to possibly reach ketosis on the very first day of your fast. Find out more about this here.

How many extra calories will you burn in water fasting ketosis?

Most people, including the so called experts, will tell you that weight loss comes down to calories eaten versus calories burned.

But water fasting ketosis can offer one huge advantage when it comes to melting away that stubborn body fat.

Because, according to modern science[2], water fasting ketosis can help you burn an extra 325 calories per day!

So that's on top of everything you'll burn because you're not eating food.

Why does this happen?

Well, your body will have to work much harder to extract the needed energy from your own body fat reserves, than it would have to if you actually ate food.

So all that extra work your body will need to do to extract, convert, and burn off the calories stored in your own body fat reserves, keeps delivering a major fat burn boost for as long as you stay in water fasting ketosis.

The #1 problem with water fasting and ketosis

Even with all the fat burn blockers gone, your body still won't be able to extract enough energy from your body fat reserves alone.

It won't matter that you already reached your highest possible fat burn rates, your body will still need to extract some energy from your vital body mass too.[3]

Yes, even after reaching full ketosis, your body will still be forced to burn away some of your muscle mass and vital organ tissue for energy. Just so you can survive the water fast.

One study[1] has proven it's possible to destroy as much as 13 pounds (5.9 kilograms) of your vital body mass during a 21-day water fast.

That destruction of your vital body mass is the price you will have to pay to hold on to those high fat burn rates in water fasting ketosis.

PRO TIP: Go here for a diet that can help you fully reverse that destruction of your vital body mass WITHOUT slowing down your fat burn rates in any way.

A common mistake people make in water fasting ketosis

One of the biggest mistakes I've seen people make is try to stay as active as possible during ketosis. Some people even force themselves to exercise, no matter how tired they feel after reaching ketosis during a water fast.

And the sad part is, I have yet to meet anyone in the water fasting community (even among the "professional" fasters), who understands just how big of a problem this can be.

In one study[4], people exercised at a pretty normal pace after they already reached full ketosis.

And the crazy thing that happened was that they destroyed over 100 grams of their lean body mass per EVERY SINGLE HOUR of exercise.

So not only will you lose some of your lean body mass (that's even if you stay completely inactive during a water fast), but you WILL destroy a lot more of it, if you force yourself to exercise once in ketosis.

So yes, you might burn off a few extra grams of body fat if you stay active during a water fast. But this extra fat loss will come at a very high price of the damage you'll cause to your lean body mass.

(Your lean body mass not only includes your muscle, but your vital organs as well - like your heart, for example.)

PRO TIP: It's possible to increase your fat burn rate even after you've reached full ketosis WITHOUT causing any extra damage to your lean body mass. Go here to find out more.

This is why you need to drink a lot of water while in ketosis

One last thing about the importance of drinking enough water for as long as you stay in ketosis.

(That's on top of the fact that it's a very good idea to keep your body properly hydrated at all times for health reasons.)

Drinking enough water keeps your metabolism revved up.

More precisely, without enough fluids, the calorie burning process in your body called "thermogenesis", will slow down.

You can learn more about the calorie burning process of thermogenesis (and many different ways of boosting it) here.


1. Owen OE, Smalley KJ, D’Alessio DA, Mozzoli MA, Dawson EK. Protein, fat and carbohydrate requirements during starvation: anapleurosis and cataplerosis. Am J Clin Nutr 1998;68:12-34.

2. Ebbeling CB, Swain JF, Feldman HA, et al. Effects of dietary composition on energy expenditure during weight-loss maintenance. JAMA 2012;307:2627-2634.

3. Cahill GF. Survival in starvation. Am J Clin Nutr 1998;68:1-2.

4. Lemon PW, Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol Respir Environ Exerc Physiol 1980;48(4):624-9.

David Brown

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