Getting in protein with a milk allergy

Considering VSG in September or October (when I will have the money), and have seen the post op diets on line.  Most recommend a clear liquid diet with lots of protein in the first weeks.  Does anyone know of any protein drinks that are milk/casein free.  I use a spirutein protein based shake now, but it is not a clear liquid.  Since I have a lot of food allergies, this may be a bit difficult for me.  Any ideas?

Might want to check with your NUT about that one.