I'm having trouble identifying a cartoon movie I watched as a kid. It was about a boy who could travel in time and, after exploring many different eras, he goes to the future and discover our society is gone and humanoid creatures now inhabit the earth in a tribal-like culture.
Every day they pray in a circle so food would spawn in a certain point while some of those praying would be absorbed by the ground. The boy asks one of this humanoids critters and they tell them this is normal and necessary. The boy then discovers a huge structure under the ground that is absorbing this critters and using their life power to power machines, and in trade they offer the critters food, so they would not fight against this system, even though the critters themselves were unaware of what was happening and simply accepted they had to be "absorbed".
My guess is that this movie may be around 15 years old, I watched it in portuguese and the translated title was something among the lines of "O Garoto da Maquina do tempo" (the boy of the time machine) but I don't get a single coherent Google result when I try searching it.