In the next patch we plan to address balance issues with overpopulated colonies. At the moment it’s possible to maintain a population twice the size that the colony should be able to support.
We’re going to speed up (x10) the rate at which a population size decreases when a colony is overpopulated (based on the planet’s limit, not the limit supported by farms).
So it will still be possible to overpopulate a planet temporarily, but to do so long-term and on a large scale won’t be feasible/worth doing.
We don’t have a date for the next patch yet but wanted to give you a heads up of this coming change.