Very intersting... I started paying closer attention to the kids a few years ago. You are correct... they do not care for vegetable juice - or salads... unless you cover them with something sweet. Also - they do not overeat and will skip meals at times - say they are not hungry. They also do not want to eat when they are sick - will eventually sip OJ... They do not like "exercise"... but love to play.
I have no problem feeding them OJ all morning... they absolutely love the stuff - no problem letting them eat when they want...etc. They prefer cooked potatoes/beans/vegs for dinner however... but will always ask for fruit as well. We have tried just fruit for all their meals - it does not fly well..... I venture we either corrupted them enough in the first 3.5 years.... or the fruit we get here is not the best quality... or a little of both... sad really.
Man oh man... does society do a number on us !! We are forced to eat milk, cereal, grains, vegs, and meats at a very early age.... generally taught to clean our plates, eat a LOT, eat often, wake up early, get in line, be on time, be like the others, exercise...etc... Kids are truely wise (innocent and trustworthy).