It’s that time of year again - Nov 15- Dec 24 is the Eastern Nativity fast, and while I could not in good conscience call myself a Christian these days I still think it’s a very smart tradition!
I won’t be fasting 40 days, but I am thinking of taking the opportunity to see how much I can push it with Fat Fasting, IF, and a few 36-72 hour fasts … at the very least it will save me from the pre-Christmas celebratory carb overload 
That would be impossible for me.
I have reached a comfortable ‘goal weight’ ( really it’s my body set point that I am trying to change )
I can barely go 3 days fasting now, without supplementing with fat so my metabolism doesn’t slow down.
I get you - I however still have quite a bit stashed away to feast on! 
I think for me the restriction is more along the lines of too much of a fight or flight reaction… hence the plan to do multiple short fasts in that period.