Sure, but respecting his beliefs doesn't mean that fasting therefore has no effect on his performances.
It's not affected him before.
Does fasting make you go cross eyed in front of goal?
If anything, coming back from injury, not being as on it as he was, is probably affecting him. Either way, he's missing sitters at the moment, but can anyone honestly say he hasn't been like that during his ENTIRE Liverpool career? Most reds I know would say that yes, legend, but as well as the massive amount of goals he scored, he's also missed sitters every season he's been here, in fact, he can be on his day one of the most frustrating players in the world for it. Scores shed loads, misses as many too. Always has.
But, presuming he has fasted before (are you sure that he has?)
What?? He's 31 mate, you think this is the first year he's done it?