We've got a long, long, long way to go before half the world is starving to death.
We produce ~77 million tonnes of beef, using (at the 1:25 ratio) 1925 million tonnes of feed.
Africa currently imports most of it's grains, let's take a generous estimate of ~75 million tonnes of grain. Add another 25 million tonnes for their local production.
And we're still off by a factor of 19x.
Food production capacity is a non-issue. Availability to the people who need it is the real problem, and that is primarily about our willingness to aid those who need it and make some personal sacrifices for the greater good.
I wish people who say that would actually live in the overpopulated regions of the world for just 1 month.
People need to stop dragging 19th century nonsense into a globalized economy. Regional carrying capacity is certainly a thing, but the primary constraint in most areas today isn't food (which is, after all, rather easy to ship and process) but water. Anyway, you can apply the same reasoning to migration as I did to food. It's just not really an issue outside of political utility. The US alone could support literally billions of people if we gave a shit about anything other than money.
Tokyo? Seoul? Manhattan? London? Paris? All very dense. Also very economically efficient. All have great metro systems, so it is easy to move around.
Of the top ten on that list, at least 5 would be considered desirable places to live by most people. If the criterion is "better than most other countries in the region", it's more like 9 out of 10 (Gaza Strip is pretty bad).
By contrast, many of the lesser-populated regions/countries are considered to be horrible places to live. As I scan down the list, it looks like there is only a very weak correlation, at best, between population density and "would I want to live there".
Obviously, your mileage is going to vary. Nonetheless, I bet you'd rather move to The Netherlands (#33) than Afghanistan (#153).