I am for smoothies and Protein drinks. Most of the time, I do get my protein from foods, but sometimes, my tummy just doesn't want food. And a protein drink is an acceptable choice. My surgeon is totally okay with a protein drink or two, so long as they are instead of a meal rather than in addition to (he made the distinction when I asked if it was okay to continue protein drinks in the morning)
Most mornings, I have a shake rather than food because it sits better. My tummy does not like food before 10 a.m., and since I'm generally awake and on the move at 5 a.m., I need something to fuel my morning. The shake does it.