PN/Grappler's Nutrition?

No, I don’t “do MMA,” but my current goals are more focused on developing profiency in jiu jitsu than anything else. Thus, my question…

If I buy Berardi’s “Precision Nutrition,” is there any need for his book “Grappler’s Nutrition”? I read the sample chapter of GN, and it seemed like basic stuff I already know. I’m considering buying PN because, while I know a lot, my knowledge isn’t systemic. I want to fill in (my probably large number of) ignorance gaps.

My guess is that I could apply the principles from PN to my specific goals. But I would be interested in hearing what others who have seen both books/programs think.

Thanks in advance.