As the audience mill into the performing space in the Pleasance attic writer and performer Katie Greenall is performing the Cha Cha Slide against a backdrop of glitter streamers and three balloons that spell ‘FAT.’ Greenall explains the significance of the song, remembering that as a nine-year-old her mother gave her the CD as something she ‘might exercise to.’ The first of many emotional gut punches is delivered.

In a series of sketches, monologues and movement pieces FATTY FAT FAT tells of Greenall’s relationship with her body and, more worryingly her loved ones’ attitudes to her size. The performer beautifully articulates the constant struggle to find acceptance in a body that is deemed unacceptable by society. A sketch where an audience member plays a doctor who is keener on steering Greenall into weight loss surgery than fixing her non size-related injury will be painfully familiar to anyone who has faced prejudice from the medical community.

Skilfully directed by Madelaine Moore, the hour showcases Greenall’s talent for disarming honesty which endears her to the packed room. Sometimes she touches her body tenderly, sometimes she thumps at herself angrily – there’s an internal fight happening and self-acceptance is a work in progress. Through this piece of theatre we are asked to examine our own prejudices, or relive moments we may have chosen to forget – the playground jibes or interactions with strangers who think calling a person ‘fat’ is a clever comeback.

The show features a mass audience participation exercise – we play ‘Never Have I Ever’ with bags of crisps, taking a bite every time Greenall mentions something that has happened to you personally. A cacophony of chewing breaks out as familiar anecdotes stack up. We watch Greenall fill her own mouth with crisps until they spew out onto the floor. It’s a moment that’s visceral and hard to watch without welling up, indeed many audience members seem to collectively have something in their eye.

FATTY FAT FAT is a funny, tender, poignant and important show which doesn’t tie the story up in a neat bow because life isn’t about convenient happy endings. Greenall has created a piece of art that will live with you long after you leave the room and will make you excited to see what she creates next.