The story is set in 2040, 26 years after the zombies started rising - it's not a story about how an unprepared world deals with the initial outbreak, it's a story about how civilisation & society work afterwards, what the new normal is. And it's also a political thriller - set in the run-up to the US presidential election of 2040, specifically this is set during the Republican candidate nomination process/campaign. So in one sense it's not really a story directly about zombies at all (although I wonder if the longer series arc will be more directly about causes & cures for the zombies). But in another sense the zombies are an all pervasive presence, altering all sorts of default assumptions about the world, and opening up new possible ways for misguided people to commit atrocities in the name of the "greater good".
The zombies are well thought out and have a satisfactory feeling explanation. Basically the premise is that two different created viruses interacted in a completely unexpected way once they were out in "the wild". The Kellis virus was created to cure the common cold - and was designed to be as infectious as a cold. It worked, too, even released into the wild before testing was finished by some terrorists (acting for the "greater good", of course!). The Amberlee virus attacks cancer & a small handful of people had been infected with this & cured. Again, a working virus. But once someone with the Amberlee virus also caught the Kellis virus ... well, when they died they got back up again. No longer with any intelligence or higher brain function, just driven by the need to feed, to get fuel to make more virus and to pass on the virus to new hosts. At low levels of Kellis-Amberlee virus, while you're alive you'll just never get a cold, never have cancer. And the combined virus is as infectious as a cold, so everyone everywhere has a low level of virus. But once you kick over a threshold - by coming into contact with more virus (like, say, being bitten by a zombie) - then you get viral amplification & turn into a zombie. And death of a host also leads to viral amplification, so the dead rise up and become zombies.
The ramifications on society are pretty well thought through - like, there's whole ranges of blood test machines with varying degrees of accuracy depending on your price range, and to get into a house or even some cars you have to get tested. Just part of life, somewhat tedious, till it saves your life. Or doesn't. Varying degrees of accuracy doesn't mean sometimes there are false negatives, oh no, only more false positives - better to err on the side of accidentally putting a bullet through someone's head when they weren't a zombie than the other way round! People don't like crowds (just takes one to go into viral amplification ...), so the net is even more important as a way of interacting with people. Of course, being inside your sealed little house with its tests on the doors isn't necessarily safe - what if someone has a heart attack & dies? Bingo, one zombie outbreak coming up in your house. Forensic science is pretty much dead - if someone dies, you don't hang about trying to establish cause of death etc, you put a bullet through the brainstem right damn now to kill the zombie (that works, just like the movies tell us). The CDC is trying to find a cure - and if you have religious objections to damaging your body after death then you can donate it to the CDC for them to cage it & use it for research rather than cremate it.
The story is mostly told from the point of view of Georgia Mason, born after the uprising - so this is her world and always has been. She and her brother (Shaun) and another girl Georgette Meissonier (known as Buffy) run a blog site and have been invited to join one of the potential Republican candidates as he campaigns, as part of the official press presence in the campaign. Blogging isn't the same thing as now, but it felt like it could have organically grown out of the way the web & blogs work now - given the zombie apocalypse did happen. When it all kicked off the traditional news media reacted the way you'd expect - "it's a flu, don't panic" "no such thing as zombies" "government taking care of it, no need to worry". So the places that took it all seriously, that provided the information people needed to survive, were blogs and other amateur news sites. So they've had a big gain in credibility (and in taking themselves seriously), it's a proper mainstream alternate to TV news or newspapers. George, Shaun & Buffy are three different sorts of blogger, providing (along with their teams) the three sorts of content that people want to see on a blog site of the time. George does news - sober factual pieces, or well thought out opinion/editorials. Shaun does sensationalist stuff - hair-raising things for armchair thrillseekers. Buffy is a "Fictional" - stories & poems & such. She's also their tech guru (the other two are better with guns and with actually going to zombie infested areas - "the field").
Obviously, once they get on the campaign trail with Senator Ryman bad shit happens that involves zombies and zombie attacks and conspiracies. And George & the others are the people who track it down, who work out what's going on, who (at a pretty high cost) break open & defeat the conspiracy. Although I worked out the primary "bad guy" quite easily, I didn't spot all the wider ramifications, and there was some stuff that was completely unexpected (but solid and "right", and the foreshadowing & set up is all there I just didn't see (didn't want to see...) it till afterwards).
If I had just read that paragraph and not read the book I think I'd've rolled my eyes a bit - how come a bunch of 20-something journalists/bloggers are the ones to save the day? But I think the characters and background of George & Shaun make it feel believable, that they'd keep poking at the information trying to work out what didn't fit, go looking for the real truth behind it. They aren't blood siblings - they were adopted as babies by the Masons, a couple who had just lost their son to a zombie attack. It's a pretty dysfunctional family - the Masons (parents) are obsessed with ratings and publicity and keeping their own blog site/brand high up in the rankings. And how better to do that than to "charitably" take in two orphans, and "give them the childhood your own son was deprived of"? There's a bit early on where George talks about how their parents never show them affection unless there's a camera pointed at them. Not an outright abusive household, but a neglectful one more concerned with external appearance and external show than with love, or trust. George and Shaun only trust each other, and are a bit too close in an obsessive co-dependant fashion - I read a couple of reviews after I'd finished the book (at Dreams & Speculation and Jawas Read Too) both of which nit-picked about the relationship between George & Shaun as OTT and unrealistic. But I thought it was meant to read like that - this isn't normal, this is the product of a screwed up childhood where the presence of a camera meant you were loved and cherished but otherwise, nothing. So they've turned to each other in an unhealthy way. And I think that's also what gives George her drive to always look for the truth - she may tell herself (and everyone else) that it's about journalistic integrity, but I feel like it's really that she grew up in the middle of so many lies about her family told by her family that she's got just a bit obsessed with looking behind the curtain, behind the spin, to find the real truth. The ultimate cynic - "if they're talking they must be lying, what's really going on?".
Something else I haven't mentioned so far is the plays on words and such that goes throughout the whole thing - right from the title "Feed" (zombies have a need to feed, the news comes via RSS feeds, camera feeds) to the fact that a lot of children are called some form of George because George Romero became a hero (his films turned out to be incredibly helpful teaching the world how to deal with the uprising).
All in all, a really good book. There are bits & scenes that have stuck in my head since I finished reading it a few days ago, and I've kept thinking about not just the story but the characters & the world it's in too. It was nice to have a different take on the zombie story - this wasn't the apocalypse, civilisation didn't collapse, people are all still people like the people you meet every day, in some ways it's life as normal except where it's so very not. Which I think helped to make it feel so solidly real & plausible to me.