I've done it before and please ensure you get enough nutrient Post-fast. I was on keto and went on water fast for 48 hours once every 3 weeks for 3 times in total.
I felt great and amazing but I also lost a lot of hair.
I have a lot of hair to begin with but it was a lot of hair and stress for months.

I did my blood test and was very low on iron which resulted in the hair loss.

Do ensure your macro nutrient are adequate after the fast.