My last post was half there ? TRYING AGAIN... about my whey LOL.
Your surgeon's plan will probably include more than just protein shakes for your daily consumption. You will probably be encouraged to eat a lot of pureed foods (soups, etc.) as well as yoghurt, cottage cheese, etc.
Don't forget, your body will also be consuming your stored fats, so you won't be in harm of starving. (Although, your head will be telling you that you are!)
I'm about 4 1/2 months out and it's just been a couple of weeks that I've been going over 500 calories and that's just because I'm upping my protein because of more exercise.
I, too, was concerned that calories were too low but my dietician said that as long as I was getting the protein in to not worry about calories. I've never been hungry, that's for sure, and feel healthy and well with great energy.
Good luck!