Fish, Plankton, Protein From The Sea

It's retro-post time: Back in 1976, a movie called Logan's Run. As with many such ventures, it's based on a book of the same name. They share some basic elements though: a futuristic society in which people are euthanized at a fixed, young age (21 in the book, 30 in the movie) and the main character is operative who's charged with enforcing that rule.

Anyway, you might think it's worth a look. I've never read the book, though, so you're on your own there.