I can help! I had to figure all this out recently.
I have a very cheap digital scales that lives on the kitchen island lately.
When making something like a salad for example, I weigh each ingredient then feck it aside in a bowl. I take note of the weight.
I then look up on www.nutritionix.com
- or similar and work out the calories going into the pot overall.
You then know the overall "calories count" of the whole dish. Then divide and conquer.
For bread, for example I eat a lot of sourdough poppyseed from Lidl. I googled their bakery sheet, found my exact bread. Calories will be listed per 100g.
I slice my bread, weigh it (takes seconds) and know the calories.
Even for butter, I put the knife on scales and set to zero. Swipe butter on to knife, and know the exact amount of calories.
Ira helped enormously - I can tell before weighing what my bread is in calories, I'd never laden a slice of bread with butter now I know the calories. It's made me very aware.
Anyway, I'm seven weeks doing this and I find it very easy now.
I am often putting thr amounts into my phone so it's stored, then quickly work out the calories of my salad (lots of small ingredients)
People will have all sorts of ways, you get quick with it very easily.
Good luck!