Meet the poster girl for plus-size pop stars

Lizzo glides into the boardroom of her London record label, looking every bit the superstar trying – but not too hard – to be anonymous. Huge, black, glittery sunglasses disguise her eyes, framed by a glorious sleek mane of hair; a black cloak is wrapped around her shoulders. She ignores my outstretched hand, instead majestically pulling my head into her bosom (she's 1.7m) for a half-hearted hug.

"I feel I'm gonna pass out," she exclaims. "It's so weird." She bends over and starts yanking at her snakeskin cowboy boots. "I'm gonna take this damn shoe off. Eurgh!"

The boots are chucked on to the floor. "I just want to be naked," she continues, pulling down the zip on her black trousers. "But I can't, socially. Anyway, it's f***ing freezing outside."

Musos have been aware of Lizzo for ever, or at least since 2013, when her debut album, Lizzobangers, with its unique blend of pop, funk, soul and hip-hop – music that she describes as "Aretha Franklin's rap album" – was released to rave reviews. Since then, there's been another album, tours with girl band Haim and Florence and the Machine and recordings with Missy Elliott and the late Prince.

But this is the year that Detroit-born, Houston-raised, classically trained flautist Lizzo, 30, looks poised for international superstardom, with her latest single, the addictively bouncy Juice, playing seemingly everywhere and boasting – to date – more than seven million views on YouTube. Rolling Stone called it a "near-perfect retro-funk nugget that would have felt just right on a mirror-balled dancefloor in 1982", adding, "If life were fair, this would be as big as Uptown Funk" ("Life IS fair … mainstream media ain't," Lizzo retorted on Twitter. "This fat, black girl working on it tho.") This summer, she's touring constantly, promoting her new album, Cuz I Love You, including a slot at Glastonbury.

"I've been laying so much groundwork but now this is the moment," Lizzo chortles, while I wonder, if this is Lizzo off-form, what full-throttle Lizzo might be like. "I have the most disgusting analogy for what I am – it's a pimple. It's been growing, growing, growing, and the more visibility the pimple has, the more aware you are of it. And when it pops – it pops."

This isn't just about the music: Lizzo has also – quite deliberately – become a poster girl for the body positivity movement, urging women of every colour and size to share the confidence that she – both in person and in her work – exudes. Her 2015 song En Love sums it up with its lyrics, "I think I'm in love, I think I'm in love/ I think I'm in love/ With myself," while her videos are packed with scenes of her shimmying joyously in a leotard, cellulite-marked thighs on full display (her back-up dancers, the Big Grrrls, are all plus-size).

Just after we meet, she's all over Playboy, supine in fishnet tights and a fuchsia bra. "Playboy did feature one type of woman for a long-ass time – big-ass kitties with a flat stomach and white skin – so it's kind of cool to be a big, brown girl in Playboy," she said on her Instagram Stories.

"Confidence is perceived," says Lizzo. "I come across as a self-confident person and I might be, but I'm definitely working on loving myself and the more I work on it, people are like, 'Ooh, wow, she must be really confident if she loves her back fat as much as she does.' I do love my back fat. But it's been a journey."

Certainly, Lizzo's rise hasn't been straightforward. She grew up the youngest of three children in a middle-class, musical, Pentecostal family who banned all secular music from the home. When she was nine, her parents – who ran various mortgage businesses – moved the family to Houston, Texas; their religion fell away and the young Lizzo began listening to a mixture of the Spice Girls, Radiohead, rap and hip-hop.

It sounds very cool but Lizzo (a blend of Lissa, short for Melissa, and Jay-Z's song Izzo) insists, with a trademark hoot of laughter, she was "so nerdy", a know-it-all goody-goody with a passion for manga. "It probably was real cute until you get integrated into public [state] school in Houston and then people were like, 'Nooo!' " As is so often the way, she tried to win over the cool kids by becoming the class clown. "Peer pressure gets the best of all of us – once I got a laugh out of the class it was addictive. I was like, 'Let's keep making these motherf***ers laugh.' "

Still, even though she started her own rap group with a couple of friends, Lizzo was always considered too out-there to be part of the in-crowd. "Even the shoes I wore were Uggs and everyone was like, 'Ooh, why are you wearing those ugly-ass shoes?' The next year everyone was wearing Uggs. I'm like, 'Why wasn't this cool at high school?' It would have saved me a lot of pain. I would have had waaay more boyfriends." She hoots with laughter. "Way more than zero."

The lack of boyfriends thing clearly cut deep. "One boy was interested in me but he was trying to keep it a secret. He was like, 'Do you want to smash after school at the apartment complex across from the school?' I was like, 'F*** in secret? Hell, no! Eurgh!' He was cute, but not that cute." She and her friends would gaze helplessly at the "black video vixens" on MTV wishing they could look like them. Never did they see an image of an apparently successful woman they resembled.

Still, Lizzo was motivated by a "vaulting ambition". "It was very Lady Macbeth, which is kind of f***ed-up; we had to do Macbeth and I did her little soliloquy about the damned spot and I was like, 'Yo, this bitch gets me!' I was very into being the best." For that reason, she ignored the teasing about her flute playing, which, pushed by her father, she started aged 12, quickly becoming virtuoso.

"I was the best flute player in Texas. My dad liked me to play to his friends, so I memorised [Briccialdi's] Carnival of Venice from the eighth grade [the age of 13], which is insane. People laughed at me, but I was like, 'Listen, y'all can make fun of me until the cows come home, but when I get this scholarship to go to college the cows will be in my farm and you ain't gonna have no milk cow.' "

Sure enough, she won a music scholarship to the University of Houston. But at what should have been Lizzo's moment of triumph things started to unravel. Confused as to whether to apply herself to classical music, rapping or simply the standard student partying, she dropped out of college and, for a while, was in a "dark place".

"I was really sad and disappointed in myself because I'd always been so ahead, so advanced in school, the golden child. So when I wasn't successful I was like, 'Who am I?' I thought my life was going to be something else and it wasn't happening."

I say a lot of women feel the same when they realise endless hard work and box-ticking still isn't enough to bring them to the top of the pile. "Yes, it's heartbreaking. You're like, 'All of my degrees and I still can't be the president? Maybe I should just go on a reality show instead.' "

Living at home, she stopped talking to her family. "I was mute for a whole summer. My mom and brother would be like, 'How are you?' and I wouldn't reply – I'd just go to my room." This led to a long estrangement with her mother, which is now healed. But things grew worse after her family moved to Denver, Colorado, leaving Lizzo homeless. For around six months, while she tried to make it with a rock band ("I thought I was going to be the next Thom Yorke"), she slept in her car, showering at the gym. Around that time, her father died. "It was unbelievably hard. It's all a blur. Now that I'm buji [high-class], I wanna go back and see what I was actually dealing with."

Much of her depression was, she says, was centred on her body image and the fact she didn't look like the Beyonces and Nicki Minajs gyrating on MTV.

"Everyone comes to a point in their life when they are looking in the mirror and unhappy, and you don't want to be unhappy any more," she says. "It doesn't matter how good a flute player I was or how good a writer, if you don't like that person in the mirror then who gives a shit? I was always woke enough to be like, 'I don't have to look like Kate Moss.' But there was nobody else out there who looked like me. If there had been, I wouldn't have had these obstacles that I needed to lose weight or change my hair or have light skin to be accepted. I would have had other obstacles, like write better songs, be a better artist, work harder – normal shit white dudes think about."

With no money for food, she was the thinnest she'd ever been. "And still, that was the worst I'd ever felt about myself," she says. It was then that she had her epiphany. "I remember one day being like, 'This is it.' Twenty-some-odd years of me believing that one day I can wake up and be some other girl. You're going to look this way for the rest of your life. And you have to be okay with that."

From there, her ascent began. At a friend's invitation, she moved to Minneapolis and began to make a name for herself in the city's thriving – though very white – music scene. "Minnesota definitely created me, the artist Lizzo," she says. "I purified myself in the waters of Lake Minnetonka and went to Paisley Park and here I am in f***ing London." Paisley Park was the home and studio of the city's most famous musician, Prince, which she visited after he asked her to record on his album Plectrumelectrum.

"Prince gave me my first big cheque and I'm eternally grateful," she beams. "Working with him has always been surreal." The pair never actually met, but they spoke on the phone. "I told him, 'Did you know you had a purple rain emoji?' and he was like, 'I do now!' "

What was Paisley Park like, I ask, hoping for some bonkers details. "It was everything, literally like all things, but I won't go into too much detail out of the sanctity. Everyone who was there knows how special it was. We were there; you can never go back."

The gay community made up her first fanbase, identifying both with her persona as an outsider and lyrics such as, "I don't need a crown to know that I'm a queen," in her ode to masturbation, Scuse Me, and Boys' "From the playboys to the gay boys/ Go and slay, boys, you my fave boys." She moved to Los Angeles, where she decided to deliberately push her unapologetic stance. "Women and men kept telling me how my music had helped them be happy with themselves, so I was like, 'Okay, I'm going to be that person in the mainstream media that baby me needed. I'm going to do this s*** so little girls in the future don't have to worry about bodyshaming holding us back.' "

In 2016, she released her EP Coconut Oil, with lyrics – "I remember back, back in school when I wasn't cool/ S***, I still ain't cool, but you better make some room for me" – that could be described as her manifesto and that helped win her a spot as a guest judge on RuPaul's Drag Race. Her message, Lizzo stresses, extends to far more people than black women. "Everyone deserves to express how they feel bad or marginalised or wrong, because this world was made for a really specific person and that excludes 99 per cent of the population."

Corporations were quick to latch on to such wokeness: soon Lizzo was modelling for labels such as Khloe Kardashian's Good American. "Just call me Glowy Kardashian bitchhhhhh," she wrote delightedly on her Instagram. Fans were less convinced. "Sis you let us down. You gotta discern which opps are worth it," was a typical comment. They were even more disappointed when, last year, Oprah Winfrey used her song Worship in a commercial for Weight Watchers, in which Winfrey's a major shareholder. A thrilled Lizzo uploaded the ad to social media only to be met by fury from many who considered the brand "toxic".

"Girl, I'm a black girl in America and Oprah to me is goals, she's like, 'Damn!' The ultimate manifester," Lizzo sighs. "So I ended up in a pretty compromising situation. I'd always been like, 'I can't wait for her to like one of my songs,' and then she did and it hurt and triggered a lot of people that someone as body positive as me would have any type of relationship with an organisation that a lot of women said had induced their eating disorders."

She removed the ad and put up another message: "Let me explain to you what I was going through and if you have any care – 'cause I'm a human being. I'm not just like some totem on the internet."

"I learnt; we talked; I went through it," she says. "I'm still like, 'Oprah, girl, do you want me to come over? I'll do a concert at your house!' "

It seems that Lizzo's war is at least partly won, as everywhere we're bombarded by body-positivity messages from the likes of Nike and Dove. But she's too smart to be complacent. "Everyone thinks things are getting better but it's kind of same shit, different day," she says. "I feel that we rebel against what's popular, so because in the early 2000s and 1990s everything was so homogenised – 'You have to be thin. You have to be light-skinned. You have to be popular' – we were all like, 'Nah, f*** you, you have to be yourself.' Now everything is so diverse, which is great, but my greatest fear is we'll end up rebelling against that and saying, 'All this people being themselves is so lame.' I saw it on International Women's Day – people growing cynical, saying, 'Please do not use International Women's Day to sell products.' It breaks my heart. I don't want us to be a trend; I want black women to be undeniable and fat women to be seen in media for ever. But it's impossible to say what's going to happen."

My fear would be that all the emphasis on Lizzo's of-the-moment activism leaves us in danger of overlooking the quality of her music, which is timeless, foot-stomping fun, with the upbeat tone preventing any hint of preachiness from the lyrics.

"I'm not 'trending'; I'm a human being," she says when I ask if too much attention is being paid to the "ishoos". "I think life can be really hard sometimes and trying to love yourself can be really shitty. But at least when you're with me you're enjoying it."

Lizzo is amused that much of her popularity now comes from the formerly derided flute, which she's named Sasha, after Beyonce's I Am ... Sasha Fierce, and that has its own Instagram account with 56,000 followers. When she performed a solo on The Ellen DeGeneres Show in America in January, it brought the audience to its feet. "I've been playing that flute in 2019 more than I have for years – I'm rusty, but I still have that tone, that vibrato. I was thinking last night, 'Damn! All that stuff Papa made me memorise is part of who I am now.' People really started to pay more attention to me as a personality with the flute. It's my dad going, 'I told you!' "

Despite the nascent superstardom, Lizzo lives a modest life in Echo Park, Los Angeles. "Isn't it funny, people think that you're rich but the people you see all over the place are usually the ones most in debt, because they owe so much money for getting that press. I don't really live too crazy. I'm very proud of my good business sense. When I got my first big cheque from Prince I decided it would go on three months' rent and buying myself a laptop. And I treat myself on food – I love food."

What food does she like? "Bread. Cake. Fries. And I love … what do y'all English have? Jackets? Yeah, jackets with the whole works: beans, cheese, oh my God!"

Right now, she's trying to eat "mindfully", she continues. "It's when you're like, 'Man, this cow is such a good cow; maybe this cow had friends.'" There's a rare pause. "Actually, that's kind of sad," Lizzo gasps. "Maybe we shouldn't eat mindfully."

She suddenly looks so mournful that I distract her by asking if she has a boyfriend. (She claims everyone is "on a spectrum" of sexuality, but admits she's "a little bit more attracted to masculine energy.")

"Hell, f***ing no!" Lizzo exclaims.

Would she like one? "It's so funny – I think I would be such a great partner to someone, but in reality I don't think I would. I just can't stay attracted to one person for that long. Last night I was thinking about this one guy, missing him, like, 'Oh my God, I just wish he was here with me,' and then I got a DM from this other guy and I was like, 'Aaargh!'" She gives girlie squeals of excitement. "So in theory I think I would be a good partner because I smell good and I'm warm, but in reality I think I'm just going to be this person for ever."

Lizzo seems very struck by this banal line of conversation. "Would I like a boyfriend?" she muses. "That's a great question. Are you trying to date me?" Lizzo gives me a saucy wink.

Lizzo's new album, Cuz I Love You , is out now.