Comedian Sara Pascoe on feminism, body image and taming the animal within

In it, Pascoe charts a hurtling journey of self-discovery as she attempts to make sense of the animalistic instincts that she believes drive us all on some level, while at the same time shining a light on the often conflicting influences that mould and shape modern women.

Far from navel-gazing, Animal provides an intimate glimpse into the dark recesses of the author's hopes, fears and crippling insecurities. Pascoe, 34, is unflinching in her candour, from the "cycle of self-hate" that has seen her "aiming since childhood for invisibility" to white-hot pangs of sexual jealousy ("an ugly trait and I'm ashamed of it") that char her soul when she pictures her boyfriend with other women.

On the day we are due to speak, Pascoe is running late. An unexploded Second World War bomb has been discovered near her home in Lewisham, south-east London, throwing public transport into disarray. "It's quite exciting," she says, after much breathless apology. "Better than the usual 'leaves on the line' excuse …"

There is an initial hesitant shyness about her that, given the book's bold and bawdy subject matter, is unexpected and disarming. Perhaps, though, it is understandable, given the power imbalance that comes from knowing that the owner of the disembodied voice at the end of the phone is already familiar with your deepest secrets.

The chapters are packed with scientific fact and quirky nuggets about the social and sexual behaviour of primates, as well as the reproductive anatomy of the mallard duck and other creatures.

The real grit, though, comes in Pascoe's willingness to hold a mirror to her own perceived shortcomings and hack into the emotional scar tissue with a scalpel of sharp wit and shrewd observation. Her words are raw, refreshing and oddly reassuring.

Take her love-hate (mostly hate) relationship with her looks. "I want to stop hating my body because it is so time-consuming and because it makes me so sad sometimes," she writes. "I get angry at myself about how lucky I am to be healthy and alive and how stupid it is to cry about how you look in a bikini."

Pascoe details what she describes as periods of "disordered eating" from being a heartbroken teenager who existed on two apples and a couple of Diet Cokes ("I checked myself for symptoms of anorexia – I wanted hairy arms; when you had the hair, you knew you'd made it") to deliberately starving herself in her mid-20s when a relationship with a man "incapable of love" ended.

Pascoe's issues with body image run deep. Her book outlines a jarring internal struggle that leaves her feeling "ashamed", "vain" and "a shallow waste of humanity" who spends far too many hours in front of the mirror "prodding, sobbing, trying everything on and deciding not to leave the house".

She concedes to feeling conflicted about sharing her experiences in this vein. "I had little battles with myself because I did think: 'Oh, I could just omit that,' but I also thought that that could give a false impression that suddenly I was someone who was very content with myself," she says.

"It is tempting to go: 'We just need to love our bodies no matter what.' I love hearing women talk about themselves that way. But then I feel like I've double-failed because I know I should love myself and not care, yet I don't love myself and I do care. I sometimes feel like a terrible feminist."

Pascoe insists she wanted to be honest and tell the world: this is my reality. "I'm 34 and too clever to feel like this, yet I still do," she says. "It is an ongoing battle. I don't want to be vain, narcissistic or spending 70 per cent of my time thinking about what I look like when I leave the house.

"I want to be able to concentrate on other people and do good things – that is my reason to be annoyed with it and to wonder why I care so much."

She admits to being cautioned regarding some content of the book. Her agent expressed concern about Pascoe sharing private details of a teenage pregnancy and subsequent abortion with the caveat that once it was "out there" it could be brought up in any future interview.

Pascoe doesn't care a jot. Sex education, she believes, should involve women who have had terminations talking about them and answering questions. "No shame and more prevention – that's my motto."

Her own abortion took place on her 17th birthday. Pascoe recalls a series of vivid snapshots: waiting, bare-bottomed, on a chair in a cold corridor; the foreboding sight of stirrups hanging above the operating table; and waking up afterwards sobbing in a curtained cubicle before drinking sweetened tea that she says tasted like freedom.

While Pascoe professes to have no regrets, this isn't a topic she views lightly. "If you've had a pregnancy terminated, I don't think that feeling goes away," she reflects. "You grow old with that decision and test yourself sometimes.

"Someone asked me: 'If you found out you could never have children, would you then regret your abortion?' It is an interesting question because I still don't think I would. That pregnancy wasn't something I could put on hold, then wait and see if in eight years it was suddenly the right time.

"Writing it down for the first time, I found it very emotional because I was trying to find the right words. When that passage was finished I was really pleased because it felt like something was excised from me and it then felt separate."

If this interview seems melancholic so far, I'm not selling it very well. Pascoe is funny, smart and has a clever knack for weaving black comedy into her anecdotes. She alludes to always being somewhat left-field. At 12, when many of her peers were developing their first tween crushes, Pascoe was obsessed with marbles, gymnastics and the curse of Tutankhamun's tomb.

"I was weird at secondary school," she says. "I didn't know how to blend in. I was very opinionated. I never did anything I didn't want to. I was very strident and at school that was terrible because you do need to compromise.

"I was very moralistic. I set up an anti-bullying line which made me quite unpopular. I was always doing these things and then wondering why no-one liked me. Looking back, I was horrible.

"I remember reading Germaine Greer at 13 and then the next day in a drama lesson a boy had called another girl a prostitute during a scene – I beat him up. I thought that was feminism and how you stopped misogyny."

Pascoe has come a long way since then. While she doesn't claim to have all the answers, she does possess an empathy which resonates. I'm curious as to her take on feminism now?

"Feminism doesn't mean we all have to agree," she says. "My first rule is real kindness towards other women even if they hate what I'm saying and I completely disagree with what they are saying.

"It is a little bit like worrying about our weight. We don't want feminism to always be in-fighting with each other when there is big stuff – such as wages, childcare or child brides in other countries – which we would all agree need our focus and attention. Let's stop nit-picking on what Kim Kardashian should be doing on the internet."

She doesn't hold back, though, in describing cosmetic surgery as a form of self-harm. "I think the fact it is advertised on the Tube or celebrities talk openly about it makes us forget [how serious it is]," she says. "I know someone who had a breast enlargement in Poland because it's cheaper there.

"I spoke to her after the operation and she cried. 'No-one told me it would hurt,' she said. I thought that was terrifying. She hadn't actually thought: 'It's a huge operation.' There's a knife, you're peeled open and what that feels like afterwards. It is not like having a bra fitted. Sometimes the addiction – just like with self-harm – comes from the pain because it distracts you from emotions."

Pascoe knows she could be leaving herself open to future criticism. "Part of me was worrying the other day: 'What if I hit 45 and suddenly want a facelift or some liposuction?' I can afford it, I'm in the public eye – won't I look like such a hypocrite?"

That would surely be her prerogative, I venture. "Exactly. Then I will need to talk about it and say: 'Yep, do you know what? I gave up.' It is very easy to be in your 30s when everything is pert and say, 'I'll never do it' only to put on 20 stone and change my mind. Watch this space …"

She is honest about her mistrust of men, beating any would-be amateur psychologists to the punch by acknowledging that many of her relationship hang-ups can be attributed to a childhood with a largely absent father whose multiple affairs had left her mother devastated.

Her father Derek – the lead vocalist and saxophone player with 1970s pop group Flintlock – departed for the Chicago jazz scene when Pascoe was five and thereafter was only in her life sporadically. "There was a phase in my teenage years where we saw him every two weeks, but there were big periods when we saw him a lot less," she says.

She grew up in a household of women alongside her mother Gail and younger sisters Cheryl and Kristyna. A former Harrods shop girl who later worked for the NHS and completed a PhD in genetics, Gail told her daughters that men couldn't help being unfaithful – it is in their biology. "Mum put it in rather brutal terms: men shag around, women try and stop them," she writes.

The mantra "all men cheat" became one adopted by Pascoe. She alludes to going into romantic relationships fully expecting them to fail. For the last three years, Pascoe has been dating fellow comedian John Robins and her happiness is palpable when she talks about him.

She admits, however, to regularly having to curb her angst and tendency to catastrophise worst-case scenarios (when they moved in together Pascoe sobbed as she imagined all their new Ikea furniture being unassembled again when they broke up).

She tests out her comedy material on Robins, 33, while he's pottering in the kitchen (much to his chagrin, Pascoe cheerily reveals) and occasionally they will squabble over who can lay claim to a particular line. "I'll ask: 'Can I have that?' He'll say: 'No! You can't,'" she laughs.

For the most part, though, two comedians under one roof makes for domestic harmony. "What is great about going out with another comic is that we have the same working hours and he understands my life," she says. "If I was going out with someone who had to get up in the morning, that would be hell and I'd never see them.

"We can get home at 11pm and say: 'Shall we make dinner and watch a film?' Or if we're both in town doing gigs we can go out after work. That feels really fun. It's also nice that we have an extended friendship group [with other comedians] that we share."

Pascoe has built a solid body of work in recent years, appearing on Live At The Apollo and garnering acting roles including in The Thick Of It, Being Human and mockumentaries Twenty Twelve and W1A.

She describes herself as an "accidental" comedian. "I didn't have a game plan – I wanted to be an actor not a comic. After I had been doing stand-up for about a year-and-a-half I wondered: 'Why am I so obsessed with this hobby?' I realised it was because I loved it and wanted to be good at it. It kind of snuck up on me – a little bit like falling in love."

When Pascoe was growing up, magazines such as Minx, More and Just Seventeen were pretty much gospel when it came to navigating the perils of teenage life. Does she believe that things are harder or easier for young women these days?

"The difference is the internet," she says. "I was probably 17 when I got my first email address. I didn't have a personal computer until I was 21. It is completely different now. My nieces, when they have questions about sex, periods or anything, can find it on the internet.

"Of course, there are awful things that they could see and you can't protect young people from all of that but the other side is that they can read the blogs of Lindy West or articles by Caitlin Moran."

While Pascoe professes that there was no definitive "ta-da" moment when it came to drawing conclusions on her book's subject matter, she did come away from the experience with a renewed sense of self-awareness. "I have challenged myself and poked into certain places that were uncomfortable," she says.

If Pascoe could travel back in time and give one piece of advice to her teenage self, what would it be? "It's difficult because obviously everything you do shapes who you become," she muses. "I did think that the inner monologue of telling yourself you are rubbish was some kind of fuel.

"Having an inner monologue that goes: 'You don't deserve this, you're not good enough' doesn't make you think: 'I'm going to write a novel to prove that voice wrong'. It makes you shyer, less likely to say, 'I can do that' and afterwards you spend all of your time fretting how it went.

"It is a difficult thing to let go of because it is a crutch, but I just wish I'd given less of a f*** in my early 20s and been a bit more fearless.

"I would worry about coming across as arrogant. I would have hated for people to think: 'Sara thinks she's really good and she's not.'

"That is such an idiotic thing. Who cares? We shouldn't care."

Animal: The Autobiography Of A Female Body by Sara Pascoe is published by Faber & Faber, £12.99. She will be on tour at The Stand in Edinburgh on June 19 and Glasgow on June 20. For more information, visit sarapascoe.com