Meat & veg I had done before and I’ve done very controlled macros, the difference I found here was more the explicit elimination of everything that isn’t protein. Kind of like being told to paint a picture but being given a limited palette and tools - it forces you to rethink your approach when there are new constraints.

Not sure if the craving thing is bacteria or blood-sugar levels, definitely most notable at night (when you’re eating meat you don’t tend to want a snack at 10pm) for me and bad for maybe 1.5 weeks before it eased off.