Taylor Swift tells Variety more about "how unhealthy that's been for me — my relationship with food," a subject boldly broached in her Sundance documentary, "Miss Americana."

In the new Taylor Swift documentary, “Miss Americana,” which premiered at the Sundance Film Festival Thursday night, there’s a montage of derogatory commentary about the singer that has appeared on cable shows over the years. One of the less nasty remarks: “She’s too skinny. It bothers me.”

As it turns out, it eventually bothered Swift, too.

In one of the most revealing and surprising segments of the Netflix film, Swift talks for several minutes about having struggled in the past with an eating disorder.

After being pictured facing a phalanx of photographers after she emerges from her front door, Swift is heard in voiceover saying that “it’s not good for me to see pictures of myself every day.” Although she says “it’s only happened a few times, and I’m not in any way proud of it,” Swift admits there have been times in the past when she’s seen “a picture of me where I feel like I looked like my tummy was too big, or… someone said that I looked pregnant … and that’ll just trigger me to just starve a little bit — just stop eating.”

Swift elaborated on what she’s gone through with that in her interview with Variety for this week’s cover story, saying that it was difficult for her to speak up about it for the documentary.

“I didn’t know if I was going to feel comfortable with talking about body image and talking about the stuff I’ve gone through in terms of how unhealthy that’s been for me — my relationship with food and all that over the years,” she tells Variety. “But the way that Lana (Wilson, the film’s director) tells the story, it really makes sense. I’m not as articulate as I should be about this topic because there are so many people who could talk about it in a better way. But all I know is my own experience. And my relationship with food was exactly the same psychology that I applied to everything else in my life: If I was given a pat on the head, I registered that as good. If I was given a punishment, I registered that as bad.”

In the quiet of a hotel suite, she goes into greater detail on how formative an effect that one early tabloid torpedo had on her. “I remember how, when I was 18, that was the first time I was on the cover of a magazine,” she says. “And the headline was like ‘Pregnant at 18?’ And it was because I had worn something that made my lower stomach look not flat. So I just registered that as a punishment. And then I’d walk into a photo shoot and be in the dressing room and somebody who worked at a magazine would say, ‘Oh, wow, this is so amazing that you can fit into the sample sizes. Usually we have to make alterations to the dresses, but we can take them right off the runway and put them on you!’ And I looked at that as a pat on the head. You register that enough times, and you just start to accommodate everything towards praise and punishment, including your own body.”

She hesitates. “I think I’ve never really wanted to talk about that before, and I’m pretty uncomfortable talking about it now,” she says quietly. “But in the context of every other thing that I was doing or not doing in my life, I think it makes sense” to have it in the film, she says.

Wilson, the director, is proud of Swift for taking up the subject with such candor. “That’s one of my favorite sequences of the film,” she says. “I was surprised, of course. But I love how she’s kind of thinking out loud about it. And every woman will see themselves in that sequence. I just have no doubt.”

The filmmaker points out that there were clearly plenty of people who didn’t think Swift was too thin back in the mid-2010s. “You can also just not notice people being really skinny, because we’re all so accustomed to seeing women on magazine covers who are unhealthy-skinny, and that’s become normalized.” Even with non-celebrities, Wilson says, everybody’s a body critic. “It’s incessant, and I can say this as a woman: It’s amazing to me how people are constantly like ‘You look skinny’ or ‘You’ve gained weight.’ People you barely know say this to you. And it feels awful, and you can’t win either way. So I think it’s really brave to see someone who is a role model for so many girls and women be really honest about that. I think it will have a huge impact.”

As much as Swift may be seen as a role model for speaking frankly on the subject, she’s got her own favorite artist, so to speak, when it comes to advocacy for women’s bodily self-image issues.

“I love people like (actress and activist) Jameela Jamil, because she says things in a really articulate way,” the singer tells us. “The way she speaks about body image, it’s almost like she speaks in a hook. If you read her quotes about women and body image and aging and the way that women are treated in our industry and portrayed in the media, I swear the way she speaks is like lyrics, and it gets stuck in my head and it calms me down. Because women are held to such a ridiculous standard of beauty. We’re seeing so much on social media that makes us feel like we are less than, or we’re not what we should be, that you kind of need a mantra to repeat in your head when you start to have harmful or unhealthy thoughts. So she’s one of the people who, when I read what she says, it sticks with me and it helps me.”

In the film, then-and-now photos illustrate just how thin Swift had gotten during the “1989” era, versus the healthier look she sported by the time she toured behind the “Reputation” album in 2018. Swift says that her under-eating in that earlier time severely affected her stamina on tour.

“I thought that I was supposed to feel like I was going to pass out at the end of a show, or in the middle of it,” she attests in the documentary. “Now I realize, no, if you eat food, have energy, get stronger, you can do all these shows and not feel (enervated).” Swift says she doesn’t care so much now if someone comments on a weight gain, and she’s reconciled “the fact that I’m a size 6 instead of a size double-zero.” Swift says she was completely unaware that anything was wrong in her double-zero era, and had a defense at the ready should it come up. If anyone expressed concern, she’d say, “‘What are you talking about? Of course I eat. …. I exercise a lot.’ And I did exercise a lot. But I wasn’t eating.”

Few women viewing the film will fail to nod their heads as Swift describes the impossibility of any body shape or size living up to all the standards for beauty. “If you’re thin enough, then you don’t have that ass that everybody wants,” she says in the film. “But if you have enough weight on you to have an ass, your stomach isn’t flat enough. It’s all just f—ing impossible.” As she became aware of the problem, Swift says in the film, it would cause her to “go into a real shame/hate spiral.”

The word “shame” comes up elsewhere in conversation with Swift, who by virtue of becoming one of the most celebrated women in the world has also had to deal with more catty comments than almost any celebrity in the world — and hasn’t always succeeded in shaking it all off.

“I was watching a Netflix Brené Brown special on shame, because I read a lot of her books, because I have dealings with shame every once in awhile,” Swift tells Variety. “She was saying something like, ‘It’s ridiculous to say “I don’t care what anyone thinks about me,” because that’s not possible. But you can decide whose opinions matter more and whose opinions you put more weight on.’ And I think that is really part of growing up, if you’re going to do it right. That’s part of hoping to find some sort of maturity and balance in your life.”

She continues, “I don’t expect anyone with a pop career to learn how to do that within the first 10 years. And I know that there’s a lot of bad stuff that’s gone on recently, a lot of really hard stuff my family is going through, and a lot of opposition and feeling pressure or suppression of one kind or another. But I am actually really happy. Because I pick and choose now, for the most part, what I care deeply about. And I think that’s made a huge difference.”