I did the HMR fast a few years ago and it was okay. I was not really hungry after the first few days. I am required to lose about8% pre-op so I am trying to eat more like I will after surgery - smaller portions, hgiher Protein, Water IN BETWEEN meals, not with... - but as I get closer I will be switching to liquids at least one week post -op. I am not sure yet because I am still a few months out (Jan).
Good luck! And (((HUGS)))