A lot of the time with restrictive diets, it seems best to start fully strict for like a month to establish a baseline, then add things in slowly so you can see the effect of each new food.
I personally found with carnivore, for example, going completely strict for a month gave me a good feel for what the pure diet felt like, and then as I added things I saw changes that I actually liked because I felt less restricted and had a better appetite. For others though, I read many people feel best on 100% strict carnivore. I think each person has a different strictness that’s optimal for them that can only be found through experimentation.