I think water increases metabolism...it contains 0 calories...and if you drink enough of it...eventually it just makes you pee clear. So...well...that means it's pretty much just circulating clear through your system. I dunno if it's "increasing metabolism"...but...I'm also rather confused as to what "metabolism" means...the rate at which you burn calories?
I usually think of metabolism as like...hmm...well, ok, I guess rate overall. Like heartbeat/breathing/eating/pissing/shitting...sleeping...
I don't think any food really increases heartbeat much, at least not that I've noticed.