Gossip girl: Meet the indomitable Beth Ditto

For the singer and gay icon Beth Ditto, confronting prejudice is a way of life. She talks about fat, fame – and feuding with Katy Perry

I know what you're probably thinking, because I'm thinking something similar as she greets me, her short hair dyed crimson, her face fresh and clean of make-up, glaring disdainfully at a solitary lychee, left behind on the hotel room's coffee table by an inconsiderate Australian radio crew: another Beth Ditto interview? Hasn't she been featured on enough magazine covers already? Done enough nude photoshoots? Stumbled into the paths of enough paparazzos on her way out of Bungalow 8?

Not to do down Ditto herself, who, quite apart from being overweight and gay (which you knew already), is delightful (which perhaps you didn't): clever, funny, sweet, joyous even when hungover. But I've always suspected the fashion mags of featuring her so they can pat themselves on the back for achieving their fat and lesbian quotas, then go back to size-zero sex kittens for the other 11 months of the year. Were I a real cynic, I might even suspect some of her fellow celebrities of befriending her for similar reasons. Having now met her, however, if only for one hungover hour, I know there are far better reasons to be her pal – such as, for example, her cleverness, funniness, sweetness and/or joy.

She flicks the unfortunate lychee from the table and watches it roll across the carpet. "I don't think putting me on the cover gives magazines permission to go on [featuring straight, size-zero models]," she replies, when the idea is put to her. "Do you really think they need permission? If I weren't on there, I don't think they'd give a shit or feel guilty at all. Maybe they should feel better about themselves for it, but I'm not there to change the minds of people at magazines, I'm not there to soothe their guilty feelings. I'm there to make other people feel rad."

Ditto, now 28, has devoted at least the past decade of her life to making other people feel rad. She just got back from the Reading Festival (hence the hangover), where she and her band Gossip incited a stage invasion during their set. "It's important," she says, "for people to feel like they're at a party."

Gossip, part of the Pacific Northwest punk scene since 1999, broke into the international mainstream in 2006, with the release of their third album, Standing in the Way of Control, and its infectious title track. Along with guitarist Nathan Howdeshell and drummer Hannah Blilie, Ditto produces raw, unadorned punk rock, which just happens to translate into pop gold. Their new album, Music For Men, had rock super-producer Rick Rubin at its helm, and is perhaps less scuzzy than its predecessor, Ditto's voice more soulful.

Following up the record that made you famous is famously difficult but, she insists, "I never get sick of playing 'Standing in the Way of Control', I never get sick that it makes people happy. There are bands who resent the song that got them attention. But I feel really lucky. And I honestly don't have any expectations for this record to be any better than that."

In case you're wondering where the "The" in "The Gossip" has gone – they were known as such until soon after Standing in the Way of Control – getting rid of it was Nathan's idea. "There were a lot of 'The' bands about," Ditto explains, "and we didn't want them to think we were in on that. Also, Nathan does all the artwork and it was more aesthetically pleasing. It sounds ridiculous, but you can centre 'Gossip' on a record cover more easily than 'The Gossip'."

It would be nice to hear this explanation from Nathan himself, but he's absent from the lush suite where Ditto is holding court. The singer has spent the entire afternoon doing interviews, while her bandmates were only required for 10 minutes all day. Does it bother them that people only seem interested in their frontwoman? "They love it. Even when all three of us are in the room, I seem to do all the talking anyway; I'm just that way. It's normal that people always want to talk to the singer. Even when it was just kids doing 'zines they always wanted to talk to me."

But people don't want to talk to Ditto simply because she's the singer in a band; they want to talk to her because she's an anomaly in the music business, which isn't exactly known for its wholehearted acceptance of gay or overweight women. Gossip became famous, in large part, because Ditto's personality was so compelling that the media and the masses embraced her outsized body as much as her outsized talent. Many must know her face better than they know her music.

"I don't know if that's a bad thing. I'm not someone who says, 'It's all about the music, dude.' As a woman I think the media really want to see you demonised for having a life outside your musical family. A woman has her nuclear family, and that's supposed to be all there is, and if she steps outside that role of wife, mother or daughter to become an independent personality, she's immediately criticised for neglecting her motherly duty. That's exactly how I feel about Gossip; like I should have that motherly duty to my band. If I were a man I don't think it would be a problem."

When Susan Boyle's overnight stardom turned sour, Ditto was one of many celebs to spring to her defence. Perhaps she was more familiar than most with the way Boyle's feelings were forgotten, in the clamour to make her a cipher for cultural debate "about women"? Ditto agrees – "and about age and beauty and body – and body hair. I've always known what I'm walking into, but I don't think she did. She didn't set out to be a torchbearer, and I don't think people had much empathy. Apparently, I'm part of some argument about how I'm promoting a lifestyle that's just as unhealthy as anorexia, and I'm like, 'Wait a minute, I don't even eat sugar.' I guess I joke about eating chicken legs all the time 'cause it's funny, but actually I take really good care of myself. Except for how much I drank last night ..."

Fame has its other disadvantages. Though she left her modest, conservative Arkansas upbringing behind as a teenager, Ditto remains close to her mother, who supported her and her six siblings in a two-bedroom house when she was growing up. "Hallowe'en is like Christmas in my family," she explains. "All the kids dress up and there's about 80 people there, and this year I was going to go home for Hallowe'en for the first time in years. Then all of a sudden I hear I have to go to Australia instead. I haven't told my family; I think it's gonna kill them. It's hard being in a band that travels, and the more successful you are, the more you travel."

Ditto also has an eight-year relationship to maintain, with a girlfriend named Freddie, who rarely travels with the band. Ditto tries to keep her away from Britain and its particularly nosy press corps. "Not because I don't think she could handle it, but because that's my life. Say what you want about me. Say it to my face, say it behind my back, write it on the fucking bathroom mirror, I don't care. But do not talk about the people I love. I will lose my mind. The Daily Mirror went all the way to Arkansas to look my dad's number up. I was just furious!"

As if fighting with the tabloid newspapers isn't exhausting enough, Ditto has found herself feuding with other singers, too – specifically Katy Perry, whose hit single "I Kissed a Girl" incited disapproving comments from the Gossip camp. The song, it has been suggested, is a shallow, trendy, faux-homosexual pose which is designed to titillate Katy Perry's male fans. In Britain, I tell Ditto, we call this sort of thing "lipstick lesbianism".

"Yeah, we call them 'boner dykes'," she replies. "Actually, it was Hannah that talked shit about Katy Perry. I don't even know her. But it's a sensitive subject: we're talking about what's really going on for my people. I don't always think people understand how real it is. I had surgery about three years ago. I was in the hospital – in a liberal part of the country – and my family was 3,000 miles away, and Freddie was by my side. And Freddie got chased off out of the place and treated like shit because she wasn't 'family'.

"It was so bad that the lady next to me in the hospital room was like, 'I've never seen anyone treated that way in my life'. And I knew it was because I was gay; the rest of my time in there, I was treated like shit. That's something 'lipstick lesbians' will never experience. So yeah, 'I Kissed a Girl' is a funny little song, but now is maybe not the best time for it."

When Ditto left Arkansas in the 1990s, it was for Olympia, Washington – the heart of the "Riot Grrrl" feminist punk movement. She has always worn her queer-feminist politics on her sleeve, and like Riot Grrrl acts such as Sleater-Kinney or Bikini Kill, they bleed into her lyrics.

"Standing in the Way of Control" began as a rant against the proposed Federal Marriage Amendment, which would have outlawed gay marriage in the US; it grew into an anthem of alienation not only for the gay community, but for Americans under the Bush administration, in a world where "everybody thought Americans were crazy and stupid and slack-jawed – but really we were asking ourselves the same thing: 'What the fuck just happened to us?'"

The night of Obama's election was bittersweet for the band, who were in the studio in San Francisco at the time. Celebrations in the city were dampened by the passing of Proposition 8, which outlawed gay marriage in California. The following day, Gossip recorded "Pop Goes the World", a song about the young generation's frustration with an unjust world, and their power to change it.

Gossip were signed to Music With a Twist, a label devoted to cultivating gay artists, until it was closed down by Sony (the band's present record company). A noble endeavour, but didn't Ditto ever worry that by segregating themselves, the bands on Music With a Twist were simply cementing their outsider status (an argument also proposed by critics of the MOBO awards, which were originally intended to celebrate the achievements of black musicians)? Should gay artists really be separating themselves from the mainstream?

"Racism, sexism, homophobia – they exist. And if those special little niches were not cut out for us, we would never win awards," she counters. "In 1920, women couldn't vote. Fifty years ago, black and white kids couldn't even go to school together. Now we're talking about gays getting married, and maybe it'll take another 20 years for that to be an accepted institution. I'm not saying it's right, it's just the pattern. And until then, you have to go through these weird pockets of being marginalised, but if we didn't segregate awards ceremonies and such, women and gays and black people would never win any, because the world is racist and shitty."

One way for her to confront prejudice, Ditto discovered early, was to take her clothes off – a pleasure previously reserved for the slim and traditionally beautiful. She appeared naked in the pages of NME and Love magazine, and after stripping off during a gig at Koko in Camden, was praised by Germaine Greer for, "her intention ... to force acceptance of her body type, 5ft tall and 15 stone, and by this strategy to challenge the conventional imagery of women". Was that really the idea, or was Greer again dragging Ditto into a wider debate against her will?

"I think that was the idea, yeah. But it wasn't anything new to me. There was a whole punk movement in Olympia around being fat and female and empowered; there would be girls walking around topless with their nipples painted black, and that would be their top. That sort of shock value was familiar to me, but maybe not to the people at Koko. It wasn't a big deal to me until it became obvious what a powerful tool it could be, when other girls started to do it and feel the same way."

Though removing them might grab headlines, Ditto has always been fond of her clothes, from being the only girl in school to know who Helmut Lang or Todd Oldham were (I Googled them, they're designers); to the DIY fashions of the Olympia punk-feminist scene; to the line of plus-size clothing she recently designed for high-street store Evans – yet another way for her to help ordinary people feel rad.

These days, Ditto counts Kate Moss among her closest friends, but surely she must have resented the fashion world when she was growing up: Moss and the other size-zero models, the designers who designed only for them, and the magazines, whose covers she can hardly have imagined she would one day grace. "Yeah, I did resent it," she admits. "I still do. But I don't back away from anything. And I always say that going to fashion week and sitting in the front row is the punkest thing I've ever done."

The single 'Love Long Distance' is released tomorrow. The album 'Music for Men' is out now on Sony Records