Is a 30 day juice fast healthy? does it really detox?

No. It is not healthy because you are missing several essential nutrients: b12 is only in animal products. Protein is going to be hard to get in all the essential amino acids. On detox? Find out what that means and how it could be determined to be either true or false. I've never seen someone give a definition where they could be found out wrong.So, meaningless.