Slim-fast, Ensure, and a lot of
protein body-building drinks are really packed with
milk proteins. For those without this
sensitivity, it is good protein. For the rest of us, not so much.), etc.
I really recommend reading this page for some info about where casein may be hiding: http://web.mit.edu/kevles/www/nomilk.html
Casein is also known for breaking down into casomorphins, which can have an opiate-like effect on the body. (http://www.wisegeek.com/what-is-casein.htm) Hence, comfort foods!