Even though I haven't read the first book in the trilogy, I found the characters well drawn. And the whole eating disorder thing isn't too preachy.
From Publishers Weekly
Feeling like she doesn't measure up to her "drop-dead gorgeous" friends, Ellie tries to take control of her weight, and ends up battling bulimia, in the second book in Wilson's Girls trilogy.
From School Library Journal
This second book in the series continues the story of Ellie, Magda, and Nadine. They are acutely aware of the size and shape of their bodies, and Ellie realizes that she doesn't measure up physically to her slimmer friends. She begins a dangerous flirtation with anorexia and bulimia, and begins to exhibit the behaviors that often go along with eating disorders, such as lying to parents, hiding food, and exercising obsessively. Ellie isn't the only one with problems--Magda's chronic dating and flirting nearly lead to date rape, and Nadine is crushed when she makes the first cut in a modeling contest but then bombs miserably. Luckily, the girls have one another and understanding and supportive families. Wilson sugarcoats the serious issues with humor, but manages to get the message across without appearing didactic.
Reviewed with Jacqueline Wilson's Girls in Love
Starting ninth grade is more difficult than Ellie imagined. She's self-conscious about her hair and weight, and she worries about her father and stepmother. Worst of all, she's not prepared when her two best friends, Magda and Nadine, find boyfriends. Girls in Love, the first title in the British Girls trilogy, explores the three 13-year-olds' forays into romances both real and fantasized (Ellie invents her own guy). In the follow-up, Girls under Pressure, the friends face body-image challenges, sexual harassment, a lost modeling competition, and, in Ellie's case, a flirtation with anorexia. Readers, even those unfamiliar with the frequent British slang, will immediately take to Ellie's voice--all lighthearted, acerbic teenage wit and mercurial despair. They'll also appreciate the sensitivity and humor Wilson uses to show how common adolescent dilemmas become extraordinary events for each girl. Expect the girls' third adventure in the fall.