Hi
@Cana - Initially when I was trying to work out where I was with things, I weighed stuff, but I approached a little differently to others thus far.
For me, things like leafy veg, say, cabbage, I viewed that as being "free". Obviously cabbage does contain some carbs, but you would have to eat a substantial mountain of it to accrue a high carb count. On that basis, I knew I never needed to feel hungry - especially as I might, or not decide to butter my cabbage for additional decadence.
For meat; that didn't see too tricky. I ate what I'd always eaten. I enjoy my meat, and it's carb-free, unless processed.
For nuts etcs., which sort of feels like what you're asking, this is where I did things differently - especially if nuts were to be my "I'm hungry and nobody's feeding me" food. (My OH is the main cook at home.) I also always had a small bag of salted peanuts in my handbag, so that I'd never starve.
In your shoes, if you have no idea how much you'll need to eat, I'd fill my little pot, then weight it (and note the weight) and then get on with my day. If I didn't et any nuts, they'd be around for the next day, but if I did eat some, I'd eat what I wanted, but then weight the pot and any remaining contents when I got home. That would give me my actually eaten amount.
In my mind, if I decided 30, 40, 50 or 100gr was a serving, and I'd mentally feel "obliged" to consume that amount, whereas my way, it was menatlly easier for me to vary my porrtions?
OK - all slightly bonkers, but that's more to show there are many, many ways to skin this particular cat.
It can take a little while to establish a good, easy routine, but preparation really helps in the early days.