Child who is a COMPLETELY different person when hungry, but insists they are full?

Our son just turned 5, and we are dealing with a very predictable pattern.

When he is well-fed, he is a wonderful kid. But if he gets hungry, it is like a switch flips. He becomes completely dysregulated - screaming, irrational, inconsolable, impossible to reason with, and often very aggressive.

The frustrating part is that he almost never realizes he is hungry.

At meals, he will declare "I'm full" after eating what we know is not nearly enough. We try encouraging him to eat more because we have learned what happens, but he insists he is full.

Then 30ish minutes later - though sometimes almost immediately - the meltdown starts.

At that point he will still insist he is not hungry and refuse food. Eventually, after a long battle, we get him to eat and within minutes he is back to his normal, happy self. If he does not eat enough, the behavior returns.

His pediatrician has done blood work, thyroid testing, and parasite testing, all of which were normal. He is also growing extremely well (48.5", 56 lbs at just over 5 years old).

I should add that he is not a "picky eater." He eats almost everything, including more "exotic" foods like sushi, octopus, escargot, fish/seafood, etc. He just does not eat in an adequate volume to avoid this pattern of dysregulation.

Has anyone experienced something similar? Did your child outgrow it? What helped prevent it?

This is more than "hanger." His behavior when hungry is extremely concerning and he is happy, funny, affectionate, empathetic, and generally cooperative when well-fed.