Incorrect, you still define them, but this shouldn’t be done in the void loop, regardless of whether or not you’re using Blynk.
I think you should start by reading these:
http://help.blynk.cc/getting-started-library-auth-token-code-examples/blynk-basics/how-to-control-anything-with-blynk-app
http://help.blynk.cc/getting-started-library-auth-token-code-examples/blynk-basics/how-to-display-any-sensor-data-in-blynk-app
Pete.