I tried it a few years' ago, so it might have improved/changed since then - but to be honest I wasn't too impressed. It seemed to all be based based on one guy's view and he is quite rigid in this. All food seen on a spectrum from green ("clean" / unprocessed) to red ("junk" / ultra-processed). In theory, everything is allowed but you should try to eat more towards the green end most of the time.
While some of the discussion and ideas were good, some of the research seemed a bit suspect - a lot of picking and choosing to back the guy's existing ideas.
There was a strong idea that the more untouched a meal is, the better (or "greener") it is - i.e. you could have the same ingredients but they are seen as better closest their natural state (e.g. a hunk of meat and raw veg), which would be towards the green, than combined and cooked in a meal (e.g. a stir-fry), which would be amber. I'm a bit uneasy about this approach. I think food has a huge cultural significance and you can / should enjoy good home-cooked meals every day (like the most healthy societies in the world do).
I felt a lot of the message was to treat "food as fuel", not necessarily to enjoy it, with the odd treat/blowout. That didn't really sit right with me - and if you have had an eating disorder, I'd say this is probably not the most sensible route to go down and that the spectrum (if it is still part of it) would potentially be triggering.
There was also a lot of aggy behaviour by both the guy and some of the group. I kept my head down, but there was a lot of "naming and shaming" of certain people in the group who challenged the ethos (even when they weren't trying to be difficult) - which made me feel uncomfortable and was part of the reason I quit.
I have since lost weight then by tracking what I eat and then slowly changing my bad habits (but not having any definitive "rules" and eating tasty home-cooked meals most of the time).