Jennifer Weiner has long been aware of the sort of writer she wants to be. "I knew the kind of books I loved myself, which perhaps aren't considered great literature, but are great stories, with strong characters and smart observations," she says. "You might not stop and gasp over every sentence, but those books get put in lots of beach bags, and taken on lots of aeroplanes, and read in lots of hospitals: they keep people company and they make them feel good. Those are the books I wanted to write."
Weiner has certainly made good on that ambition, writing 11 novels in 13 years, selling 15 million copies in 36 countries and spending a cumulative 249 weeks on The New York Times bestseller list. Her debut novel, Good In Bed, sold more than 1.6 million copies alone; her second, In Her Shoes, became a film starring Cameron Diaz and Toni Collette.
More recently Weiner, who is 44, has been making waves in the usually polite world of publishing with her outspoken views, often aired on Twitter, over the treatment of her genre by the literary media. When Jonathan Franzen's novel Freedom was published in 2010, she pointed out the disproportionate, to her mind, amount of attention his work was receiving, particularly in the New York Times, and coined the term "Franzenfreude".
Weiner was not disputing the quality of Franzen's work, merely highlighting the fact that, despite its enormous popularity, "commercial fiction" is not reviewed anything near as much as "literary fiction". In response, Franzen recently published an essay in which he lamented the effect of social media on serious literature, referring to "Jennifer Weiner-ish self-promotion".
An unashamed devotee of popular culture, Weiner believes that this isn't simply a matter of snobbery, whereby "art" is valued over commerce and populism, but that a gender bias is at play too, against fiction written by and for women. Nick Hornby and David Nicholls, she argues, also write humorous, highly commercial fiction, often about relationships, but are widely reviewed and highly regarded.
"I do think there is an inherent double standard," she says. "What men produce is deemed art; what women produce is deemed craft. Women make quilts and people say, 'That's adorable, let's put it on the bed.' Men make a painting and people want to hang it in a museum."
Nor has Weiner held back when other female writers - including Claire Messud and the Pulitzer Prize-winner Jennifer Egan - have disparaged and sought to distance themselves from "chick lit". Most recently, Lena Dunham, the creator of the television series Girls, claimed to loathe "airport chick lit". As Weiner points out, "I'm sure she has just no clue that these books she's reviled may have in some teeny, tiny way made her show possible."
While she simmers with righteous indignation over such dismissive attitudes, Weiner appears well compensated for her work, at least. On a hot July morning she greets me at the door of her sprawling wood-and-glass house on a cliff top in Cape Cod, the Massachusetts resort famously frequented by the Kennedys. Her main home is in Philadelphia but Weiner spends every summer on the Cape, with her two daughters from her first marriage, Lucy, 11, and Phoebe, 6, her boyfriend Bill Syken, 45, a journalist and fellow novelist, their excitable jack russell terrier Moochie, and a tribe of friends and family.
Weiner's feisty social-media spats might suggest that she takes a certain pleasure in provoking a fight, but in person, cross-legged on her sofa, she could not be less antagonistic. Like her books, she is witty and sharp, but also sincere, and stands firmly by her criticisms. "What I regret is that it often comes across more as anger than disappointment," she admits. "I was devastated when Jennifer Egan, whom I respect so much, was asked for her advice for women writers, and said, basically, 'Don't write chick lit'.
"Any woman who ever put pen to paper, or finger to laptop, has had to deal with sexism, discrimination and double standards, has had to fight harder than a man to get published, to get noticed, to get reviewed, to get profiled," Weiner says. "I'm not saying that we all need to hold hands and sing Kumbaya, but I wish that there was some recognition of what the real problem is. Chick lit is not the problem."
While Weiner herself doesn't shy away from the label, her heroines can't be said to conform to chick-lit stereotype, often being significantly overweight, or, in the case of Ruth in The Next Best Thing, facially disfigured. "One of the frustrations of my life has been the paucity of characters who look like me," says Weiner. Although she is certainly not big - a size 12 to 14 at most - she was, she says, always "Fat Jen" in high school.
"There are lots of invisible women out there," she continues. "They are not on TV, in movies, or ads - bigger girls are only allowed to be a "before" on [the television show] The Biggest Loser. There are older women too, all sorts of women with different challenges, who are invisible. I wanted to put all those women on the page, and to give them happy endings."
Well intentioned as all this is, mightn't it also be a little misleading? Could fairy tale endings in fiction lead to false expectations of real life? Weiner pauses for thought. "If my books are saying, 'There's a guy out there who will love you, there's a job out there that you will love and be great at, and there are wonderful things in your future', then, I think, it is a necessary corrective to a world that tells these women that they are worthless, over and over again," she says. "As someone who was that girl, and as someone with daughters, I strongly believe in saying, 'Even if you don't fit the mould of what the world tells you beautiful is, you can still have a happy ending.'"
When asked by aspiring writers for career advice, Weiner often quips that they need to have had an unhappy childhood. The oldest of four children, she grew up in suburban Hartford, Connecticut, a bookish child with few friends. Her father, a psychiatrist, was "loving and thoughtful and my biggest fan ... except when he wasn't", she says. "He was very unpredictable, and that was hard to live with."
Harder still was her parents' divorce when she was 12. "My understanding was that your dad moved into the condo on the other side of town, and you saw him on weekends and Wednesdays, but he was a part of your life. My dad just left. He was done with being a father and done with being a husband. He wanted to be more like a 'fun uncle'," she tells me, still in some disbelief.
Then, when Weiner was in her 20s, her mother, Fran, came out as a lesbian. "I didn't see it coming," she says. "But the thing my mother always told me was, 'It's all material,'" she says with a laugh. "And it was."
Weiner has openly mined the rich seam of her own life for novels. Cannie Shapiro, the protagonist in Good In Bed, is a reporter on a Philadelphia newspaper - as was Weiner - with a father who abandoned the family when she was a teenager and a mother who comes out as a lesbian. Her latest book, All Fall Down, is concerned with middle-class addiction: its protagonist, Allison Weiss, is a blogger on a parenting website who begins by popping a few too many painkillers, then develops a serious opioid addiction and ends in rehab.
The inspiration for the character came from Weiner's father, who died in 2008. The two were estranged, but when Good In Bed became a bestseller he called her to ask her for money. He also turned up at a public reading a few years later, delivering a speech about how art comes from suffering and how, because he had caused her to suffer, she owed him everything, including a lot of money.
"Then I got a call from the police department in his small town in Connecticut, because I was the next of kin," she recalls, becoming visibly emotional at the memory. "They told me he had died from an overdose of crack and heroin. I had no idea he'd even been a drug user."
These days she is close to her mother, who spends the summer with the family in the Cape Cod house, along with her partner. "I only saw my grandmother twice a year. I wanted the girls to have a different relationship with my mother and her partner."
After leaving school, Weiner went to Princeton University, where she began her feminist avenging in earnest by taking on - and managing to get banned - the all-male "eating clubs", the equivalent of British dining societies and a hangover, literal as well as metaphorical, from an era of single-sex education and privilege.
"I think I have always had a willingness to point at something and say, 'This is wrong,' even if I got grief for it," she says, shrugging.
Weiner wrote her first two books while working as a feature writer for the Philadelphia Inquirer, only giving up journalism when it became clear that she had a future as a novelist. But success came at a cost, putting her marriage to Adam Bonin, a lawyer, under strain.
In 2010 the couple separated. "My career began taking off just as he began to encounter the first stumbling blocks he had ever had to deal with," she tells me. "Men are wired to be the breadwinners. Adam was and is successful, very bright and very good at what he does. But the noise around me is different to the noise around him. The other way around, women are okay with that - we are raised to be okay with that. But it is a rare man who can be with a woman who is successful. And it's a hard line to walk, because you don't want to be self-effacing or falsely modest, especially having daughters. You don't want to pretend to them, 'Oh, it's just this little hobby I have.'"
As children of divorce themselves, the couple struggled with the decision to split up after eight years of marriage but, she says, "It came down to both of us wondering, 'What do we want to show our daughters about love?' Not just companionship, not just another body on the couch, but genuine love. And that meant doing a hard thing - leaving a marriage."
They have an amicable relationship these days: Bonin lives a few doors down from Weiner in Philadelphia and in summer is a frequent weekend guest in Cape Cod. "I think we are better parents to our daughters now that he is never in a position of holding my bag while someone takes my picture," Weiner says with a wry smile.
I ask whether being in a relationship with a fellow writer is easier or harder. Syken, who pops in several times during our interview, and cheerfully fetches lunch from a nearby deli for us, is, Weiner says, "very confident in himself, and very happy with what he does. He's not competing with me and I'm not competing with him."
Would she marry again? Weiner nods eagerly. "I'm waiting ... Waiting for the ring," she says, laughing. "But I'm not in any hurry - we're very happy as we are."
She also hopes to see a shift in the sexist book world. "Someone once asked Stephen King, 'How did you turn the corner from being seen as this schlocky, horror, vampires-and-werewolves genre guy?'" she recalls. "And he said, 'A lot of the critics who didn't get my work either retired or died'."
King is now a respected writer - he is reviewed in the New York Times and published in The New Yorker. "If we keep making noise about the way women's books are perceived, marketed, sold and discussed, I think that in 10, 20, 30 years' time, I am going to look at the New York Times' book reviews and see something different than I'm seeing now."
All Fall Down, by Jennifer Weiner (Simon & Schuster), is out now.