[insert bro-science disclaimer here] The volume of food you eat may be "normal" but the calorie density might be lower. The trick to increasing or decreasing calorie intake without feeling like you are stuffing yourself or starving is to keep the volume pretty much the same and tweak the calorie density.
Do you happen to have any links to descriptions of the densities of various foods? I've been aware that this is a good strategy for a while, but haven't been able to find anything that systematically discusses various food types and how they rank (as opposed to individual tidbits such as, hey, carrots have very few calories but are pretty bulky, so munch away).
I don't have a list, but I've developed a feel by tracking calories on MyFitnessPal. Over time you notice what food helps you hit your calorie goals while also being good (which is extremely subjective).