I often get asked my opinion on the optimal length of a fast, unfortunately I don’t ever have a clear answer.
To be honest, a 24-hour fast isn’t THAT much better than a 20-hour fast, in the same way that a 20-hour fast isn’t THAT much better than a 16-hour fast, which of course isn’t THAT much better than a 12-hour fast. However, this doesn’t mean that a 12-hour and 24-hour fast are basically equal.
The same logic can be applied to longer fasts that go beyond 24 hours.
The way I see it, the optimal length of fast is largely dependent on what you are expecting that particular fast to do for you.
If you were to try and find an optimal fast length based on fat burning, or autophagy, or Growth Hormone response or insulin levels, they all might have answers that are close to one another, but they probably won’t be exactly the same. And the answer you find may not be optimal for you and your current lifestyle.
In other words, it simply may not “fit well” with you.
And herein lies the problem – There probably isn’t an exact optimal fast length that is right for everyone, every time.
So in the end what we’re left with is the basic idea of “taking a break from eating” as being the goal of our fasts – a way to reduce overall calorie intake and as a way to pause and then reset our daily eating habits.
A pattern interrupt of sorts that allows our bodies to take a break from eating and digesting, and that allows us to segment our eating periods down to manageable periods of a few days at a time.
So on any given fast, the right length is the length that allows you personally, at that specific time, to reach these goals. For me, sometimes it’s 24-hour fast and other times (when I’m in a really good flow) 20 hours may be optimal.
Looking back, I think the idea of “Interrupt, Pause, Reset” is maybe the most important aspect of this style of fasting. It reinforces the idea that with Eat Stop Eat it is still about eating, and the fasting is a way to balance out our eating, rather than a way to get rid of it completely, or to push it into a small little window.
Interrupt, Pause, Reset.