A related article on inflammatory (meat-based) diet with causation for depression/anxiety.
https://medicalxpress.com/news/2022-07-depression-linked-consuming-inflammatory-diet.html
You completely misread that study write up.
The author never mentions “meat” or “protein.” What is mentioned is the need for foods with antioxidants.
All it talked to was their finding on veggies/fruits/fibers and implied that other considerations were out there, but they didn’t test any of those.