You're absolutely correct.
A few years ago I went gluten free to see if it helped with some other health issues (it did, NCGS.)
So, between late 2016 and the end of 2020, I avoided gluten as best as I could. Which all but eliminates most fast food and the majority of prepackaged foods/snacks/etc.
Portion control became incredibly easy. I ate when I was hungry. Sometimes people would comment on how little I was eating, but I was still energetic and kicking ass at work/etc. My body also fairly quickly started to adjust to a more 'proper' weight. (As long as I wasn't drinking. There were parts of that time of my life where I sometimes did, never to where it interfered with work but definitely was hiding from my personal life circumstances.)
ANNNNYWAY. Late last year I decided to try gluten again to see whether I still had a bad reaction and/or if it was moreso specific types that caused me issues (They all kinda bother me, but barley makes me ragey....)
I remember the first thing I ate from McDonalds last year. It was a double cheeseburger.
I then spent the next 2 weeks straight getting at least one meal a day from McD's. It was an eye-opener on how addictive some of the components in a food can be to your neurons.