I´ve been chasing my tail now for three years, or two and a half. I know how it feels. Yes we improve, but not enough. Enough to survive yes, but not enough to actually feel triumphant and start living.
I have to say that YES we need to do big, rather permanent changes and stick with them for long. Only that way you can heal. Personally I think I need to be more consistent with gluten, dairy and fruit among other stuff.
Anything that has a negative impact on your health is what makes you stay in the loop. I stopped drinking and eating good stuff at Christmas long ago, but that wasn´t hard for me. My vices lay elsewhere, it is a personal thing. I am still struggling with them. For instance I am addicted to fruit, which I don´t digest, and also to arguing with people which really stresses me... etc