We are living through the peak Earth population right now; it will likely be degreasing in 50 years.
It's simply that people in developed countries don't want to deal with the trouble of raising more than 1 or 2 kids because raising kids is difficult and expensive. You need 2 kids to replace the 2 adults, but then you add in other mortality factors and it drops below replacement.
Most of those people aren't agreeing that there are too many people, hell in cases like Japan, even their governments want them to have more children, they're just focusing on what strikes a balance for their comfort.
World hunger is not caused by too many people, it's entirely caused by our priorities. World produces more food than it needs and that production grows faster than the population.