It happens. You're going along, eating your greens and feeling great…and then, PIZZA! It seems like a special treat, and you deserve it.
(No argument here, by the way. I like pizza too.)
You feel alright, so you rationalize some other treat – like beer, or cake, or more cheese. Then you decide since the pizza went fine the one time, you may as well eat it again….maybe with a beer this time…
…and before you know it, your day-to-day is full of all the stuff you've been avoiding, because you KNOW it makes you congested, or interferes with your sleep, or makes you burst into tears for no reason.