Meal prep and 'portion control'

There are a lot of posts on this sub of meal preps showing 'portions' of meals that are about a quarter of what one adult would eat. One 'portion' of normal rice is about 1/4 cup cooked rice. <br><br>How do you figure out good, healthy 'portions' and how much food do you need to prep per person and meal? I'm cooking for myself and I'm very aware of 'portion control' when it comes to not over eating, but my meals are so small since I don't know how to calculate portions properly. <br><br>TLDR: How do you figure out good meal sizes for your meal prep?