hey France - i measure out my portions before I start eating, so that way if i don't notice my body telling me to stop, at the very least i've run out of food. My nutritionist told me no more than 1 cup (8oz) at a meal/sitting. If i want a little variety and more than one taste in a meal, then i reduce the size portion of stuff I'll consume. As an example last night I had 1/2 a cup of canned green Beans and 1/2 a cup of vegetarian baked beans - but i measured it before I ate it to help me from overeating.
if you are still hungry after the 1 cup portion my recommendation is to change activities - do something else for a while - and if it's an hour later and you're still hungry, then have another 1/4 or 1/2 cup of something.
also, make sure you're fully hydrated. sometimes i mistake hunger for thirst and i'll eat something only to still have the same feeling in my body - but it turns out what solves it is a drink.
