Extended Water Fasting: How To Do It Safely

Water Fasting: How To Water Fast Safely Image

This is a very touchy subject with most people. That is only because they do not understand how the human body really works, especially when in a fasted state. They think you’ll waste away. They think you’ll lose all your muscle. This is not true. Water Fasting will cause you to lose weight, and some muscle, but you actually often lose less muscle than on a regular CICO diet.

Firstly, I should mention a few things. One, you can perform a water fast for as long as you like, depending on your goals.

There are many variations of lengths of fasting. Going from generally shortest to longest, the most common ones are:

11-12 Hour Fast

This is probably the easiest to follow. Fast for 11-12 hours of the day, eat between the rest. The fasting time includes sleeping, so you’d only have to abstain from eating for 3-4 hours after waking or before bed if you sleep 8 hours a night. The reason we start off here, is because this is the shortest time period of fasting, shown to cause a positive effect on the body.


Probably the most common type of fast, you fast for 16 hours a day, and consume all your calories within 8 hours. When I practiced 16:8, I preferred fasting for 6 hours after waking, and 2 hours before bed, consuming my calories between those hours.

23:1 (OMAD)

This is starting to get a little farther on the scale now. With this practice, you consume all of your calories with a one hour period of the day. It’s can also be known as OMAD, or One Meal A Day.

Alternate Day Fasting

This is the act of fasting all through one day, then eating normally the next, and repeating. You can combine this with other types of intermittent fasting, such as 16:8, or OMAD, which in the latter you would eat one meal every two days.


Eat for 5 days, fast for two. Some people switch it about, and fast for 5 days, eat for 2.

Extended Fast

This usually means a fast that is longer than 5 days. This is the one we’re going to be focusing on.

An extended water fast can be either a few days, to a few weeks. Some people have gone months, but they had a very high amount of body fat. The longest time someone went water fasting was 382 days. He lost 276lbs, from 456 lbs – 180 lbs and suffered no adverse effects by the time he came off. After a checkup 5 years later, he had maintained a weight of 196 lbs. If you want to read the study here’s a link. If you do it correctly, you will lose minimal muscle mass, and mostly fat. If you have low body fat levels, an extended water fast probably isn’t for you. Since water fasting is a way to force the body to find an alternate source of energy, namely your fat cells, if you have little fat, you will have very little energy, and will probably start losing muscle mass.

Disclaimer: You should not perform water fasting if you have any medical conditions. Always consult with your doctor before starting any extreme dietary changes.

Extended Water Fasting Safely

Only Drink Water

This may seem pretty obvious, but some people always ask if (x) will break their fast. If it has calories, it will break your fast. Other drinks like coffee and tea are allowed, but you cannot put any milk or sugar in, as these have calories. Calorie free sweetener is an option, but it could trigger an insulin response, which is what you want to avoid, so you gotta have your coffee black. Coffee has actually been shown to increase the effects of the fast by inducing autophagy. Autophagy already happens in your body daily, it’s the process of destroying old cells and replacing them with new ones. When you speed this process up, you’re getting rid of even more unnecessary cells, making sure you’ve only got the strongest, healthiest cells.

Besides it’s necessity, by drinking only water, you’re allowing your body to remove all the toxins while not introducing new ones. That’s generally how detoxes work.

Drinking water is a way to alleviate hunger. Drink often, and you’ll minimize the hunger pains. You’ll probably find your water intake doubles while water fasting (mine did at least). Get yourself a decent quality water bottle. Maybe a half-gallon jug, so you have plenty of water on the go, or at work. If you do water fasting at work, try to make sure you’re not doing any strenuous exercise, as you won’t have as much energy as you’re used to. Taking time off would be best.

Also, taking supplements like fish oil will break your fast, as they are pure fat, and naturally contain calories, and many tablets and pills are bound by dextrose, which is a form of glucose, so you’ll want to be careful with those. 1 Multivitamin a day shouldn’t break your fast, but don’t go popping 10 pills a day cause that most likely will.


Sodium, Potassium, Magnesium. Multivitamins maybe. The first three are necessary to supplement on a mid-long fast. This means longer than 4 days. Multivitamins should be taken if you’re fasting for a long period of time. Some bottled waters have added electrolytes. Most don’t, and to be honest, you don’t need to buy them.  You can get your electrolytes from simple store bought ingredients.

Salt contains sodium, but you should buy something like Lo-Salt, that used potassium in lieu of salt for its use, and either pink Himalayan salt, or bicarbonate soda for sodium. The latter has other benefits, such as neutralizing stomach acid, reduces fatigue, reduced bloating, and much more. You’ll have to experiment to find how much works best for you.

Generally, aim for a minimum of 2000mg Sodium per day, increasing if you plan on exercising and sweating a lot. You can get this from 1-2 tsp of salt. With Potassium, the RDA is between 1000mg – 4700mg every day, and 1 tsp of Nu-Salt contains 3180mg per tsp.

When you add the sodium and potassium, add it to your water, and drink it throughout the day. Consuming your RDA of sodium and potassium quickly will give you negative side effects.

Know When To Stop

Water Fasting will give you unwanted side effects. The most obvious is hunger. Luckily, if you manage to get past the three day mark, most people report that their hunger disappeared almost completely. It does seem to reoccur, but as long as you drink plenty of water and wait it out, it’ll go away. When you start to feel ‘real’ hunger, you’ll know it, and that’s when your body is telling you it’s time to stop. Lack of energy generally kicks in between day 2-4. That’s the point where your body starts to switch to using your fat cells for energy over glycogen stores. It may come back on occasion later, but if it does, supplement with some electrolytes, or maybe some bone broth in moderation.

Symptoms like headaches, cramps, or dizziness, are usually caused by a lack of electrolytes. If you feel these symptoms, take some electrolytes and see how you feel in an hour.

Nausea is the last one, and if you are feeling this, you might consider stopping your fast. But, it could also be caused by things like multivitamins. Iron does best on an empty stomach, but can cause nausea, alongside stomach cramps and dizziness. If you think it’s the multivitamins, try taking a different brand, or supplementing with one that doesn’t have iron in. It could also be caused by a lack of potassium, but sometimes it goes away if you drink some water. See what works for you, but if you are worried, break your fast and/or consult with a medical expert.

Know How To Stop

Breaking the water fast is almost as important as the beginning of the fast. If you do it wrong, and just gorge yourself on loads of food, you will generally regain all the weight lost through fasting. If you were fasting for a long period of time, generally over 5 days, you should never break your fast with lots of carb heavy food. In doing so, you can cause a condition known as Refeeding Syndrome. When you start burning fat and protein for energy, you suffer an intracellular loss of electrolytes, in particular phosphate. Not dangerously so, but lower than they’d normally be.

When you suddenly shift from fat use for energy to carbohydrate, your body kickstarts your cells uptake of phosphate, and your Serum levels drop dangerously low, which can lead to profound hypophosphataemia. This conditions leads to some very nasty side effects, the most serious of which is death.

There have been anecdotal reports of those that fasted solely for fat loss didn’t experience a lot of symptoms of refeed syndrome, but they should be taken with a pinch of salt. To prevent this, planing on breaking your fast is essential. It’s always best to break your fast with light foods/drinks. Many people recommend a watered down juice to break it, soup, or bone broth. Breaking it with some fatty foods such as Macadamia nuts, some salad with cottage cheese, or even raw veg with olive oil and vinegar, is fine too. You can break it with many other foods, but regardless of what you break it with, do so slowly. Your body hasn’t eaten anything in a long time, and you shouldn’t overtax it. So your best bet is to break it with Ketogenic foods. If you want to find out more about Ketogenic foods, you can do so here at the /r/Keto FAQ.

Helpful Tips
Water fasting tips
Dr. Jason Fungs Top 9 Fasting Tips

To keep yourself on the path of water fasting, we’ve got some tips:

  • Keep busy – Everybody knows that so often, when you eat, it’s not because you’re hungry, but because you’re bored. Keeping busy will take your mind off the hunger, and will allow you to not think about eating. This can include cleaning your house, doing work, do puzzles, play games, read, watch podcasts, go for a walk, even meditate. Do whatever you enjoy doing, or you need to do while fasting.
  • Don’t torture yourself – If there’s a cooking show on TV, don’t watch it. If you need to go to the shop for any reason, stay away from food aisles. Temptation can break so many people, and you don’t want your reason for breaking the fast to be because you saw some food you wanted to eat.
  • Drink Coffee/Bone Broth– The caffeine in the coffee will give you extra energy, making the low energy periods of fasting easier. Bone broth helps satiate you, and offers other benefits.
  • Drink More Water – You’ll naturally drink more water anyway, but making sure you’re drinking more will help stave off hunger. It won’t satiate you fully, but you won’t feel absolutely empty, provided you keep drinking, even when not hungry.

Hopefully this will give you the best idea of how to perform an extended water fast safely.

Remember that if you start to feel unwell, and are unsure how to proceed, consult with your doctor to get the best course of action, and consult with them prior to starting a water fast to make sure you’re in the right condition to do so.

Extended water fasting will give you many health benefits besides just fat loss, so it’s a great tool to use for your own health. If you want to know more about the potential benefits, check out our other article Fasting: 10 Reasons To Consider Trying It.

Blade Montane

Avid bodybuilder turned powerlifter, my passions are all around fitness and health, and sharing my knowledge with the masses.

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