Global growth rate today about 1% per year which is 10x higher than it was in Europe in the middle ages. It would be hovering around 0 if we were at capacity. In Europe, it was 0 on average between 1300 and 1400 (black death), so they were still growing otherwise but just barely compared to now.
https://en.wikipedia.org/wiki/Projections_of_population_grow...
You could speculate that our current population isn't sustainable because it depends on non-renewable resources, but that's on a longer time scale than we're talking about here.