The first one to look at is the “Hallelujah Diet. The author of this one is Rev. George Malkmus. The first problem I have with this diet is Malkmus’ claim that it is “God’s Way.” Now, in order for anyone to be able to truthfully say something is “God’s Way,” it has to be demonstrated clearly from Scripture, or it has to be by direct revelation. Since the Scripture is fairly limited in this area, and I doubt if Malkmus has had a direct revelation, I would say the claim that his diet is “God’s Way” is false.
If you want to be a vegetarian or a vegan, that is your liberty as a Christian. If you want to live on such diets because of the inhumane treatment of animals by “factory farms”, etc, that’s all well and good.