Is the Gracie Diet a credible diet?

Hello everybody! I am trying to find more information about the Gracie diet, and I’m having a little difficulty doing so. I’m looking for research into the diet and more credible sources other than the main website, which is obviously going to advocate it, and other similar sites that have a distinct bias toward it. How familiar are you with the Gracie diet? Is it something you would recommend for a client? I have a client (personal training) who is considering jujitsu, and this diet has been mentioned in a few videos this client has been watching.

The information I find about it seems to be consistent with complexities I don’t necessarily agree with. I am studying to become a nutritionist, so my nutritional knowledge is still pretty base, and some of the aspects of the diet don’t necessarily make sense to me. One part that has me asking questions is, what sort of actual research and data supports that mixing certain foods during a meal will either positively or negatively affect you? Any clarity or useful research sites anybody can recommend would be greatly appreciated. Thank you!