I also noticed in The Land Before Time III: The Time of the Great Giving, Littlefoot exclaimed how hungry he was, ate two leaves, and was satisfied. The satisfied part was proven when he stopped eating and said "That sure was good." I have never heard that expression from a child when he/she still wanted more food. I can maybe see Petrie or Ducky satisfied from that kind of meal, but I'm pretty sure that a dinosaur Littlefoot's size could eat more than a full grown human. Logically, stress from unfortunate incidents in one's invironment can lead to temporary eating disorders, things like being hungry then quickly being full. Which means, eather the creaters greatly underestimated the capactity of his stomach, didn't have the time ton show him eating a full meal, or it seems they are hiding stress related stomach abnormalities on a show aimed at children