I have done once a week 36 h fasting for some months now. My medication increases my apetite, and this helps me not gaining weight and losing it a little. The first 2-3 times were hard, but then it was easier.
I do a 36 hour fast every week. Have dinner on Sunday and then don’t eat until breakfast on Tuesday.
Then the rest of the week I do 18/6 fasting window (eat between 1pm and 7pm).
I didn’t start with the weekly fast I added it after a few months when my body was a used to the fasting windows.
Well it’s better than nothing. That said those 36 hours are gonna be hell for you since you’re gonna be “eating normally” for the rest of the week meaning you’ll never be giving your body the chance get used to that 24 hour period.
Every time you do it it’s gonna feel like a challenge. For reference I do MWF fasting and the days I eat I’m doing 20:4, sometimes Omad.