First thing in the morning hydration has also been recommended to me by a work mate who's been on some structured diet (he and his bride paid hundreds up front to be on it, she paid for herself, and he's just been doing the same, good for the relationship as well) and has been very successful.
For me, keto works best in conjunction with fasting (intermittent is easiest). I still skip dinner several days a week to give my system a rest. Have done it for many, many years...long before autophagy became all the rage.
As an aside, I used to use daily fasting (skipping dinner) as a means to stay skinny for sports (biking and running). Only recently did I learn that it is such a good cleansing, rebuilding, and healing protocol. Who knew?;-)