Unfortunately, some people can take up to a week or longer to reach ketosis and benefit from all it’s amazing weight loss and health benefits.
Now, if you’re the type of person who can wait a week, and many are, then simply following the rules of the keto diet is going to be enough for you.
At less than 20g net carbs each day, you will definitely get into ketosis. You may simply have to wait awhile.
For the rest of you, including me, the fast is going to get you into ketosis guaranteed. All within 72 hours.
Other health benefits of the 72 hour fast
Ketosis is a great state to be in. You’ll be burning fat like there’s no tomorrow.
Also, you’ll have more energy without the daily slumps that you may be accustomed to.
Moreover, you will be experiencing more focus, alertness and an upturn in your mood.
However, when you fast for 72 hours you get the amazing process of autophagy working it’s best for you.
Autophagy is the body’s natural clean and repair program.
Fasting for any length of time from 12 hours or so will trigger this healthy spring-clean.
Importantly, there is a lot of evidence that the benefits are greatly increased past the 48-hour stage of a fast.
The University of California found that fasting for three days can completely reset the immune system (1)
They described their findings as “remarkable” and not without reason.
This is a major benefit of a fast, and if you’re going to fast for say, 48 hours for ketosis it would make sense to go that extra 24 and reap all the health benefits.
The same study also found that there was a noticeable decrease in the production of the enzyme PKA, a hormone which is associated with an increased risk of cancer and tumor growth.
In my opinion, resetting your immune system and lowering your risk of cancer is more than enough reason to live on water for three days.
Plus you’ll be deep into ketosis.
How often will you need to do a 72-hour fast?
If you’re fasting to quick start your journey into ketosis, then as long as you remain in ketosis there is no need to fast again.
However, if you’ve accidentally (or deliberately!) eaten a slice of cake, a short fast of 24 -36 hours will get you back into the right depth of ketosis.
But, if you have health goals aside from weight loss, a 72-hour fast every few months will be of great benefit.
It will keep your cells and your immune system in the best possible state for health
How to prepare for your 72 hour fast
During a fast you eat nothing and drink only water, black tea or black coffee.
You should also be aware of the need to keep your electolytes in balance. You will be losing more salt than normal, and you may need to take a little either alone or in your water.
If you experience a headache, or generally feel slow and unwell, it’s probably important to think about your electrolytes. Sometimes by taking a little salt or magnesium you can be back to feeling well in no time.
Learn about this before your fast, and you may well be able to avoid this complication altogether.
For more details about the imbalance of electrolytes read this article about the keto flu:
Both fasting and begining a keto diet may cause this to be an issue for you for the first day or so.
Further, you should consider eating less carbs than normal for the day or two before you start your fast.
However, there are many who just go ahead and fast without a problem.
You’ll need to think about your own personal level of will power.
In my opinion, it is easier if you’re busy, but others feel better if they are resting or have a day off work and the gym.
Many people find that the gym is still doable during a fast, but again, this is an individual thing. If you feel unsure, then allow yourself a day off.
It’s really all about you listening to your body, and stopping the fast at any time that it doesn’t feel right for you.
After the first day, your hunger should no longer be obvious. Any pangs you do get will normally come and go within 10 minutes or so.
Further, By fasting, you will not lower your metabolic rate, as happens with calorie restriction.
A strict water only diet will keep your metabolism humming along, and will even increase it.Once you start on the keto diet, you will reach ketosis at any time between about three days and a week or more.
However, you can quick start this process by fasting for a day or so before you start your keto eating.
This way, you’ll have less stored glycogen to work through before the switchover to fat burning and ketosis can begin.
However, the evidence seems to suggest that there are so many extra benefits from stretching your fast to 72 hours, that it seems sensible to continue your fast for that extra time.
That isn’t to say that a shorter fast won’t get you into ketosis (or just the keto diet alone).
However, you’ll be missing out on some amazing health benefits if you stop your fast at 48 hours. Consider going one extra day of water only.
You’ll be benefiting from a reset immune system and a reduced risk of cancer.
For this reason, you should consider aiming for a 72-hour fast to get yourself into ketosis. This length of time with just water will guarantee that you will be there.
This should be no problem for a healthy person on no medication. However, it’s important that you listen to your body.
If you reach the 24-hour stage of your fast, or even less, and feel ill just stop.
Eating the keto way will still get you into ketosis, it may just take a little longer.