Sofie Hagen: 'If someone wants to be 600lb – they have a right to be 600lb'

Yet the Danish-born, London-based stand-up prefers that word to euphemisms such as "curvy". Fatness, she argues, is no more shameful than blondeness or having brown eyes, so why not call it by its name?

Which makes perfect sense, though as we chat over green tea in the pub, I find myself reaching for terms like larger, bigger, heavier, for fear of being deemed rude by folk at the next table.

Do fat people, I ask, whispering the F-word, really suffer more prejudice than others over their appearance? Short people get mocked too and so do thin people, as Scottish athlete Eilish McColgan discovered last week when she was taunted over the internet for being “skinny”.

"It's very hard to say what's worse," says Hagen. "But definitely what I experience is fat-phobia so that's the only thing I can talk about and know about."

Hagen says she was was fat from early childhood. Growing up in small-town Sondorso, Denmark with her underweight sister and their struggling single mother, little Sofie numbed her emotions with food and emerged as a deeply unhappy teenager whose self-loathing was exacerbated by yo-yo dieting.

As a Copenhagen University student, she realised that anti-fat prejudice was nothing but a capitalist con and that she'd been needlessly putting her dreams on hold until she reached some unachievable weight-loss goal.

So she eyed herself in the mirror, said, “Hello, hot stuff!” and embraced the here and now. And boy, has she made her mark. At 30, Sofie Hagen is a successful comedian whose latest Edinburgh Fringe show, The Bumswing, is garnering rave reviews. She's also a respected voice in the fat liberation movement and the author of Happy Fat, a sassy new memoir-come-self-help-guide that raises two fingers to a thin-centric world.

Even now, though, her new-found confidence can be lacerated by a disparaging comment. And when she tweeted that “a fat Disney Princess” might be a less damaging role model than all those tiny-waisted, saucer-eyed waifs, she was taken aback by the viciousness of the response. “Cancerous”, “sick” and a “lumbering whale” were some of the more printable insults slung by people who, writes Hagen, were simply “furious that A Fat Woman Spoke”.

Yet she doesn't blame social media for creating a climate of nastiness, arguing that it merely reflects the world as it is. “People who send me these nasty messages would feel that way even if social media wasn't there.”

In fact, Hagen is a fan of the internet, having discovered a worldwide web full of international friends aged 11 when she might otherwise have felt isolated at school. “If society didn't have a damaging and dangerous beauty standard then people wouldn't need to follow accounts that make them feel bad about themselves,” she reasons, adding that using social media “in the right way” lets you “build an entire Instagram feed” full of inspiring people who provide “an antidote to the billboards you see outside or the adverts you see on TV”.

Her beef is with the companies who own social networks. “They keep allowing Nazis to be on there and yet delete accounts by sex workers, people of colour, fat people for no reason. I'll report a tweet that says, f*** you, fat bitch I hope you die” and get an email back from Twitter, saying – 'Oh, we didn't see any overstepping of the community guidelines. Have you misunderstood it, maybe within a context …?”

Is kindness the answer? I mean, if people were less cruel, fat-phobia would go away – wouldn't it?

“In theory – yeah, if everyone had huge amounts of empathy and prioritised ethics over money-making,” she says sceptically. “But as a solution to the problem? No, we've tried that.” Women, she argues, have been smiley, acquiescent and kind for too long. “No-one got the vote by saying please, we got the vote by throwing ourselves in front of a horse. So I think we're done with thinking kindness is the answer.”

Nor does she want to be construed as some good-natured, cuddly earth mother. “We have a tendency to see a fat person as a maternal, loving, friendly person. I get a lot of DMs [social media direct messages] who say, 'I'd love to hang out with you and talk about life.

“Most things I write, I'm provocative, furious and a bit of a bitch. I talk about autonomy, rebelling against the system and taking down capitalism and rich people. You know – socialism. 'Punch Nazis' is not the kindest statement in the world.”

Hagen is refreshingly open about the practical hurdles that seem custom-made to humiliate people like her, including miniscule public toilet cubicles and airline seats, which she says are getting smaller despite the population's expanding girth.

Spending a long-haul flight squashed between rigid armrests beside someone who's unhappy about having their space invaded isn't just embarrassing, it's excruciatingly painful, she says.

So what's the answer: widen all the seats? "I would love that," says Hagen, though actually, she points out, that's not what fat liberation activists are demanding. “All we want is for the armrest by the window to be taken up to give us a couple more inches. Or maybe to have a button on the website that lets us buy two seats."

Earlier this month, former BBC newsreader Michael Buerk caused outrage by describing obese people as weak, greedy and likely to save the NHS money by dying 10 years prematurely. Couldn't tiny toilets and narrow airline seats be construed as a necessary disincentive to life-threatening weight gain?

Hagen disagrees that fatness is unhealthy per se. As for those unfortunate souls featured in US reality TV series, My 600lb Life: "What are we going to do that doesn't infringe on that person's psychological wellbeing or autonomy? Do we interfere in that person's life, tell them how to live, take away rights, bully them into trying to lose weight, force them into some kind of camp?

"People know their own bodies. If someone wants to be 600lb – then sure, they're allowed to do that. What society are we living in where we have to police other people's lives?"

What we can do, she says, is tackle inequality. Hagen, who grew up poor and now helps with poverty alleviation charity Turn2Us, argues that “fat-phobia is a huge problem within the poorest of the poor because it's really expensive to be healthy”.

Shouting at people to lose weight doesn't work anyway, she says and when last year, Cancer Research UK released billboards which used cigarette packet-style messages to declare that "obesity is a cause of cancer too", Hagen took to Twitter.

"How the f*****g f*** is this okay?” she tweeted, calling for the "piece of sh**" adverts to be taken down. The charity repeated that campaign this summer but when I raise the subject, Hagen doesn't want to discuss it. Has she said all she wants on the matter?

“Yeah. I can't comment on it.”

Later in the interview, she expresses weariness with a debate that's continued for decades without moving forward. So what needs to change?

“I'm going to be careful with this because I don't want to get my hopes up,” she says, “but at the moment there are some pretty amazing thin people taking charge. Doctors, nutritionists, dieticians who are posting about the political side of fat-phobia and destroying the myths that fat is unhealthy, that people should lose weight, that there's an ideal weight and we should eat a certain way”. She names “wellness” rebel nutritionist Pixie Turner and Just Eat It author, Laura Thomas, as well as physician Joshua Worlich, who has warned against conflating dieting with wellbeing. There's also a special place in her heart for Orange Is The New Black actor Matt McGorry, who's spoken out about the downsides of dieting.

“We need thin people to start doing something, because no-one's listening to us [fat people],” she says. “If people think I'm worthless and unintelligent because I'm fat, they're not going to listen to me making points about fatness.

“That's how oppression works: you make sure that no-one takes a group of people seriously so that they can't fight their way out of their own oppression, so you need other people. And it feels like it's happening a bit.”

Hagen herself is now “in a really good place and really happy”. But it's taken hard work and lot of therapy to get here. She says she was emotionally abused by her step-grandfather, who treated any refusal of sweets and cakes as a rejection of his love. Having previously suffered from depression, she now has “complex PTSD, OCD and anxiety”.

“I've seen about five therapists because I couldn't make anyone understand what I was experiencing,” she tells me, adding that her current therapist is a trauma expert who told her their confusion probably stemmed from the fact “it's impossible to feel the way you do and still function”.

“I feel very special,” she laughs, with a flash of the dark humour that infused her first three shows.

Those shows – which consecutively addressed depression, anxiety and emotional abuse – were exhausting, she now admits.

"My therapist said I'd been re-traumatising myself every night. I always have fun on stage, but something looms over you when you know that – this bit is funny, but in 10 minutes I need to talk about my grandfather.”

She was also becoming a magnet for other people's problems. “I share a lot about my life in the book, shows, on social media,” she says. “I also have two podcasts where I'm super-honest. A lot of people think this means they're friends with you and they tell you everything. So when you check your DMs on Instagram it's full of very personal messages about people's deep dark trauma. And you do kind of feel like … sometimes you should speak to a friend or a therapist or anyone but me because I'm not here to consume all of your emotions. I can't.”

The Bumswing is more upbeat and Hagen says she's having “more fun than I've had before”. Yet it's a show about memories, performed by a woman who says she remembers virtually nothing from the first 10 years of her life.

How does Hagen's mother feel about her daughter's childhood trauma being lived out onstage?

“My mom is a very logical person,” says Hagen. “I do an impression of her in my show. She's like, 'Well, I didn't know, so how can I blame myself?' Also, she sees me now and I'm doing really well despite everything.”

Another of the show's themes concerns a “sex holiday” Hagen took in Swansea, shortly after moving to the UK. Didn't her “sex holiday” partner mind featuring in her act? “I definitely concealed his identity,” she says. What about her family? “My mother is like – 'If we didn't want you to talk about it onstage, we wouldn't have done the things. We have to stand by what we've done. It's your life, you get to talk about everything',” she mimics, lapsing into “impression-of-my mother” mode. “I'm quite nice about her,” she adds. “I'm not slagging her off.”

She must be proud of her daughter?

“Yeah, in that most Danish of ways.” What does that mean? “You get a nod.”

Is Hagen proud of herself? “I think so, yeah. It's weird. I have friends whose childhood dream was to be a comedian, author, whatever. None of the things I'm doing now were ever goals. It just happened. It feels like I did my first gig and now I'm here, like the blink of an eye. So I think I am proud but I'm still not really processing what's happened. It's too surreal.”

What's next for Sofie Hagen? Having made her journalistic debut aged 14 “chasing Brian from Westlife through Denmark” for a local newspaper interview and later made a BBC Radio 4 programme about “clean eating”, she's keen to do more documentaries.

And she's already planning next year's Edinburgh Fringe show. “I think it's going to be called Fat Jokes,” she says. “A bunch of fat jokes that aren't deprecating towards fat people.” Can you share one with our readers? “No, but I can tell you that I'm doing impressions of thin people.” Anyone in particular? “No, just all thin people. I've heard so many jokes about fat people and what we're like and I've never heard a joke about thin people so I thought it would be fun to turn it around. Take power back in some kind of way.”

Meanwhile, she's still “really excited” about her current baby, The Bumswing, which one reviewer described as “so intricately played out that it makes The Killing look like it was created by amateurs”.

Hagen sums it up as “very much a 'no spoilers, please' sort of show”.

So if you're wondering what “bumswing” means, there's only one way to find out.

Sofie Hagen will be talking about her book, Happy Fat: Taking Up Space In A World That Wants To Shrink You (4th Estate), at the Edinburgh International Book Festival today (Saturday August 17) at 3.15pm www.edbookfest.co.uk

Her Edinburgh Fringe show The Bumswing continues at The Pleasance Dome until August 25 https://tickets.edfringe.com/whats-on/sofie-hagen-the-bumswing