Just like the latest fashion trends (to kitten-heel or not to kitten-heel) and food hypes (avocado anyone?), particular practices get thrown around among the keto/lchf crowd. While IF (intermittent fasting) and OMAD (one meal per day) are such well known practices I have also noticed that the EF, or extended fast, has been hogging the limelight recently, especially on online forums and in Facebook groups.
Extended fasting, i.e. any fast longer than 24 hours, is usually done for autophagy and metabolic healing. Another often cited reason is to free one’s mind of food thoughts and to take advantage of the high energy that may occur while on an EF.
I myself, already an 18:6 faster, regularly slip into a 24 or 48 hour fast and I specifically try to do one 90-120 hour fast every 2 months. Please note: I have specific reasons to do such a long fast, namely the aforementioned autophagy AND to help relieve PMS (and obviously I time my prolonged fasts to coincide with that time of the month).
Generally speaking, I would never advise anyone to try EF unless there is a specific reason to do one. Simply put, do not start EF just for the hell of it, the outcome of an EF is unpredictable at best and without actually checking blood markers who knows what is going inside or on cellular level. But I am also quite aware the idea of trying one can be very tempting, especially when you hear people talk about it online and you are just the curious or experimental kind.
So, for those of you who are really contemplating this, I have written down some general but important do’s and don’s to make sure you go about it the safest way possible. For more in-depth information I have linked some sources below as well.
Here we go:
1 the most important rule of all: do not attempt an EF unless you are keto adapted and/or already progressed naturally into IF of at least 18:6;
2 if you have underlying medical conditions and/or you are on medications, do not practise EF without consulting your medical caregiver;
3 if you are at goal weight, i.e. you have no high bodyfat stores to use for energy, do not go beyond 72 hours if it is your first time; you need to gauge to what extend you will lose weight first. I for example have no weight to lose AND as it turns out I actually do not lose any weight on EF beyond some water weight but for you this may not be so, in which case a really long EF is not healthy;
4 if you are UNDERweight I recommend you do not practise EF at all; if you want the benefits of autophagy IF is a much healthier option;
5 never treat EF as a quick fix for rapid weight loss; not only is that a very unhealthy mindset, it will also lead to disappointment as the majority of people will regain a sizeable portion of the weight lost once they start eating again;
6 on EF you have to make sure you get enough fluids: consume water, coffee and (green and black) tea plus you need to replenish your electrolytes (sodium, magnesium, potassium; if your EF goes beyond 3 days I advise to also add calcium, B-complex, vitamin C and D from day 4;
7 if you feel unwell at any time despite good fluid and electrolyte intake STOP your EF; never push through thinking you otherwise feel you have failed. Your health and well-being always come first!
8 do not be afraid of the hunger, usually strongest on day 2; hunger is not an ever-lasting feeling, it is actually a subsiding wave. Do not panic, be aware of the feeling but also notice how it goes away;
9 the majority of people report they feel better doing an EF on busy days, as opposed to spending days just doing nothing; this is something you will need to find out for yourself. Personally I do best starting out on 2 relatively restful days i.e. the weekend because I know huge bursts of energy start on days 3-5, when I get lots of things done;
10 let your spouse/family know you are on an EF, they can support you;
11 when you are ready to break your EF, do it very gently. Have water with ACV to prepare the stomach for food to come about 1 hour before you break. Follow up with some bone broth. After that just a light meal: eggs, avocado, nuts, cooked vegetables.
For more info please read here:
Or read this excellent book: