Omega-3 good, Omega-6 bad has been known for many years.

For example, Scott Alexander wrote in 2014 on his blog Slate Star Codex about how Omega-3 lowers crime rates and Omega-6 increases crime rates. And he links to some cool RCTs where you can check the methodology yourself.

https://slatestarcodex.com/2014/02/18/proposed-biological-ex...

Eat your fish!