Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Satirical, Dark
This one's just filled with satire. Almost everything is over-exaggerated for comic effect, like how Calista, Quendy, and Loga flit off to the bathroom many times because hairstyles have changed (in, like, the last five minutes) or how the kids are super into television shows that poke fun at brainless program. We might not have programs like Oh? Wow! Thing!, America's Unlikeliest Allergy Attacks, and Amurica: A Portrait in Geezers—but admit it. You can totally see TLC picking one of them up.
But it's not all laughs and gags. There's also disturbing stuff like Titus's vision of an environmentally destroyed world:
I saw fields and fields of black, it was this disgusting black s***, spread for miles. I saw walls of concrete fall from the sky and crush little wood houses. I saw a furry animal trying to stand up on its legs but the back ones were broken or not working, and it dragged itself with the front ones, whimpering, through someplace with gray dust, and needles coming out of the sand. Its jaws were open. (30.4)
So, light satire is just the cherry on top of the dark substance of Feed. (There we go with the food metaphors again.) Anderson's point is more serious than poking fun at empty-headed consumerism: he's saying that, if we keep it up, we're actually going to consume ourselves into extinction.
Whew.