I think the fact that you can bloat up to any weight you want just like how you can have as many kids as you want represent how primitive our civilization really is.
We are incredibly ineffective at doling out scarce resources or pricing in externalities.
I just don't expect humanity to get a handle on it for another 100 years at least. I'd say that, right now, we can't.
Just like we forced people to stop drinking during prohibition, and we force petty criminals all the time to stop doing bad stuff once caught?
We'd like to think it's the former ("we can, but we don't"), but the reality is we can't.