Does your shake count as your fluid?
Yep. Most people count any decaf liquids. Most do not count caffeinated liquids because caffeine is a diuretic, meaning it can make you pee out extra liquid.
Please note: I AM NOT A DOCTOR. If you want medical advice, talk to your doctor. Whatever I post, there is probably some surgeon or other health care provider somewhere that disagrees with me. If you want to know what your surgeon thinks, then ask him or her. Check out my blog.