Twelve-year-old Anaïs and her fifteen-year-old sister, Elena, are vacationing with their parents in the French seaside town of Les Mathes.

Later, as the girls are reminiscing together back at the house about their childhood, Elena reveals Fernando gave her an engagement ring while at the beach.

On the way back, she becomes tired and decides to sleep at a rest stop, where a man smashes the windshield of their car with an axe, kills Elena, and strangles their mother while ripping her clothes.

The website's critics consensus reads, "The controversial Fat Girl is an unflinchingly harsh but powerful look at female adolescence.

[7] Fat Girl got an "A" from Lisa Schwarzbaum of Entertainment Weekly[8] and was called a "startling vision of the prickly crawlspace between innocence and sexual awakening" by Ed Gonzalez of Slant Magazine.

[9] Carla Meyer of the San Francisco Chronicle wrote the film "[e]xposes the less sexy things that lust can awaken, like viciousness, deceit and amoral longing".

[10] Stephen Holden of The New York Times wrote, "Reboux's extraordinary performance conveys Anaïs's mixture of precocious insight, animal canniness and vulnerability so powerfully that it ranks among the richest screen portrayals of a child ever filmed".

[11] In a review for Chicago Sun-Times Roger Ebert wrote, "There is a jolting surprise in discovering that this film has free will, and can end as it wants, and that its director can make her point, however brutally".

As Douglas Keesey explains, "in the midst of the rape, Anaïs stops trying to push the rapist off with her arms and instead puts them around his shoulders in an embrace.

It could be argued that she 'acquiesces' solely to ensure her survival, but one can see how the BBFC might be concerned about a paedophile viewer showing Anaïs' embrace of her rapist to a potential victim as a model of how to consent to rape.