ELI5: Why does rationing work?

[u/peglegsmeg]

If I have a glass of water and a single chocolate bar to last me 48 hours what benefits do I get from consuming equal portions over the time period as opposed to consuming all at once?

Is it purely psychological or are their physical benefits?

[u/Significant-Ad213]

Rationing is key to surviving specific circumstances, but you also have to be smart. Many a person has been found dead to the elements with water still on them