It isn't fatal....

I wouldn't keep my cat from eating for 48 hrs.  I couldn't do it BUT my cat was trapped in a ceiling for 30 days without food and survived.  I don't know if there was water up there but when we finally found her and got her out she was minus her beautiful hair, whiskers, and had lost so much weight.  We took her to the vet immmediaely.  They gave her an IV, I took her home, she immediately starting eating and drinking and today, 8 yrs. later, she is fine. My story, for whatever it's worth

I am very glad your kitty is okay.  With that said. your story is very unusual.  It is absolutely certain that you cat both had some source of water and some source of food.  You are very lucky things worked out how they did. 

No one should ever go more than 24 hours without feeding their cat unless a vet has specifically instructed them otherwise.

Under normal circumstances, it definitely is fatal... in fact, that would be the case for any living creature lost and presumably without food or water for 30 days! Your cat must have been able to find sustenance somehow, even from small insect prey or what have you, though it's good to hear your cat pulled through and is alive and well.

She had to find water somehow. . .cats can't go more than 3 days without water (maybe less?). She probably got a bat or a mouse at least a couple times for food, too, because 30 days is a bit long to not have anything. Paradoxically, skinny cats can go longer without food than fat cats because they dont have as much fat to clog up their livers :/. Not that anyone should do that on purpose, of course, but survival stories are interesting.

Seriously, I don't know.  She was in the rafters of a ceiling in the dead of winter.  There could have been mice but when we finally found her she was just skin and bones.  When the Vet saw her he said that even one more day would have resulted in kidney damage.  We were so fortunate!   It did however take about a yr. for her disposition to come back.