There are no euphemisms. The issue I think you're having is viewing things in a an artificially binary fashion. In reality it's all a lot fuzzier. If you don't have enough resources in one area it doesn't mean everybody just starves, it instead means you work a bit more, or just make do with a bit less. And that creates a voluntary pressure against fertility. Nature even has relatively tame 'stop-loss' measures here that further reinforce this like the fact that malnutrition directly reduces fertility. So if we graph population vs time, there's going to be a trend, but it'll look a lot like a relatively low amplitude sine wave. You'd only see sharps shifts after something like a plague.