What do you mean after workout? Like right after workout, or an hour after that, or you eat ****loads a day, but only after your done with your workout?
It isn't a good idea to eat it right after the WO, because your body digest it slowly, and you don't want to have your body/blood focussing on digseting stuff after your workout.
Doesn't it say how much protein is in it? In my country, the law says it has to be on every product! Anyway, it's like 3,5 gram a 100 ml. Same as milk. It's better to take curd or cottage cheese, which contain like 9-11 gram protein per 100 ml and less to none fat.
As I said, that stuff digest slowly, that's why many bodybuilders eat it before they go to bed, it releases the protein slow, so when your asleep for many hours your body has a steady flow of protein to feed the muscles and not get in a catabolic state. | 
