The tagline is misleading: would you kill to be thin? never really makes its way into the book. Sure, there's killing, and there's being thin, and I know it's just a turn of phrase, stop being so literal about it you mock-pretentious arsehole, but I'm just saying. 
 First of all, this book is getting a little dated. I didn't notice it too often, but ten years can tell a lot. As in, Jessica Simpson is not relevant in the slightest nowadays. Most pop culture references in this book aren't relevant - or are far more relevant than they used to be. PowerPoint, for instance, is some kind of enigma to our protagonist, Heather. Perhaps her being 'computer illiterate' was a way to relate to the target audience ten years ago, but now it seems silly. Nobody could get a job in administration nowadays without knowing how to make a PowerPoint. 
 OK, maybe I'm being nitpicky. Maybe this book is just a time capsule now. A sort of ineffectual, recent one, but nevertheless all history has its value. For example, this book was written around the time when skinny-shaming and fat-shaming hadn't both been denounced by at least some parts of the cultural (Internet) mainstream. But at some points, the only thing defining Heather is her weight. She talks for a large portion of the book about snacks. I think it's supposed to be funny, but it sort of misses the mark. In fact, a comedic murder mystery is a little strange to say the least. It results in a largely bizarre overall tone, with some... 'funny jibes' during serious moments leaving you with a slightly bitter taste at the back of the ol' tongue - as does that bloody 'dorm/residence hall' joke. That was less of a running gag, and more of a marathon annoyance. 
 Then the book goes completely off track for a bit (view spoiler)[whilst she sleeps with her ex and then he gets hit with a plant pot and isn't heard from again 'til a throwaway line at the end (hide spoiler)], and sort of meanders back after a while. 
 And then there's the writing. Good God the writing is questionable at best, and gut-wrenching to your average English major at worst. (view spoiler)[That's me, by the way. I'm the English major. (hide spoiler)] 
 Cabot's prose is famously casual, but lord if it doesn't read like our narrator is fourteen instead of twenty-eight sometimes. The sentence structure veers all over the place: tangents and parentheses abound, with weird, overly-extended semantic fields to top off our pirate ship of bad grammar. Have some actual quotes, specially selected by yours truly to upset your inner literature nerd: 
 "A overflowing geranium planter." 
 "He inhales, and in the semidarkness, the tip of his cigarette glows redly." 
 Redly. I know it's a real word, but seriously. Redly. 
 Redly. 
 Also, at one point someone's voice is described as being harsh or something, and our eloquent narrator states that "not even Monet's water lilies could soften it." That barely even makes sense. 
 Sure, I didn't see the twist coming, but then again, I didn't really care. The climax was borderline ridiculous: (view spoiler)[ I'm supposed to take our villain seriously when she tells blonde jokes and then throws her head back and cackles maniacally? My friends used to tell blonde jokes in Year 9 to wind me up. It's hardly threatening. (hide spoiler)] 
 I've sort of forgotten most of the characters by this point. (view spoiler)[Except Julio, because nobody falls ten stories and gets crushed by a lift and lives. Seriously now. (hide spoiler)] 
 It was OK. Two stars I guess.