I am hope this can settle a debate.
I have 2 boys (5 and 2) and we are in disagreement about how much they should be eating in the morning. A family member has been giving 5 year old 2 Weetabix and a slice of toast and 2 year old 2 Weetabix. I feel this is too much as I could barely manage what the 5 year old is eating.
YANBU - that's too much food
YABU - let them eat what they want