Optifast - pre and post op

I have my pre and post op diets and both of them require Optifast - which seems to go against all the low carb theorys.

I've not been given an aim for Protein, carbs or calories post op, but what they have suggested doesn't cover the 'normal' standard of protein of 60/70g. Although some of it can be made up by adding protein into Soups I doubt I can get it up to the 'normal' recommended amounts, and am worried about hair loss (as I am thinning on the front anyway!!).

I just wondered if anyone else is on Optifast and what results they had?

Kathy