Sofie Hagen is probably more well-known in Edinburgh for her stand-up than for her literature and as she takes to the stage at the Book Festival it feels a little more like a comedy show than a book talk. She chooses to stand rather than sit and instead of the more conversational style most authors at the festival choose she takes to the mic and performs what is almost a one-woman show about her book, Happy Fat.

She is a consummate performer and it is no surprise that she has a host of comedy accolades behind her as she delves into an important discussion about how we view fat in society with much hilarity elicited from the subtitles appearing on the screen behind her.

However, although the book is called Happy Fat it quickly becomes apparent that Hagen is not happy about it all and in fact furious about what she sees as a world which is not made for fat people. She recalls flying to Australia and being in so much pain on the flight having squeezed herself into the too small seat that she realised on landing she could not make the return flight. There are problems in restaurants, in shops and even at the hairdressers and Hagen is on a mission to educate the so-called ‘fatphobes’.

Her book is mainly autobiographical but is also filled with the science behind the myth that being fat automatically makes you unhealthy and even if somebody is unhealthy they are still allowed to love their body.

This idea of loving the skin you’re in has formed the framework of the Body Positivity movement gaining such traction just now but Hagen is, perhaps controversially, perhaps realistically, not a proponent of this system. Instead she describes herself as a fat activist; someone who wants to teach people to not hate their bodies in the first place, to not be made to feel bad because of your size. And she makes a valid point.

Funny, engaging and passionate about her work, Hagen is a force to be reckoned with in the fight against the fatphobes.