Two 'simplistic' understandings of the Feeding of the 5000 are quite legitimately:
a) It is a demonstration of Christ's divine supernatural power
b) It is a message of how to lead our lives, selflessly offering to God whatever we have, no matter how small, and He uses it.
The danger is that the passage is so familiar that we stop there, but if we dig a little deeper there are more 'hidden meanings' as well. Here are three:
1) Jesus is fulfilling the law and the prophets: as the new Moses (repeating the miraculous feeding of the people with 'manna' from heaven; acting like Elisha (ordering his disciples to feed many from a few small loaves)
2) Message for the Jews and the Gentiles: feeding of the 5000 is for the Jewish people (significant Jewish numbers, language and place in this miracle); feeding of 4000 is for the Gentiles (with significant Gentile numbers, language and place). God provides abundantly for all people.
3) The Word of God: the bread represents the word of God for all, and Jesus identifies himself personally as that bread ("I am the bread of life"), and we see the eucharist clearly in his actions.
When we dig a little deeper we find extra hidden meaning within each and every miracle Christ performed.