Question about B-Frames and IQ

Is there any way to use B-Frames without any quality loss at all (even at high bitrates)? Maybe using settings like x/100/x/x? If not, why do B-Frams imply a slight loss in IQ and P-Frames don't?

Use the (in)famous search button:P

I don't know what to look for. If I look for "b-frames" I'll have to wade through dozens of threads that probably won't have anything to do with what I'm looking for.