In one of her most physically and emotionally demanding roles to date, Sydney Sweeney has traded red carpets for the boxing ring, transforming her body and mindset to portray pioneering fighter Christy Martin in the upcoming biopic Christy.
But this wasn’t just a case of learning a few jabs and crosses—Sweeney gained over 30 pounds, trained up to three times a day, and endured real bruises to bring the story of the 1990s boxing legend to life.
And from the early buzz, it’s clear her commitment is paying off.
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A Gritty Role Demanding More Than Just Talent
Christy Martin isn’t just a sports icon—she’s a survivor. One of the most famous female boxers in history, Martin broke barriers in the male-dominated sport and lived through a near-fatal domestic assault at the hands of her then-husband and trainer. To capture that kind of complexity on screen, Sweeney knew she had to go all in—physically, mentally, and emotionally.
“I loved it,” Sweeney told W Magazine. “I started eating. I weight-trained in the morning for an hour, kickboxed midday for about two hours, and then weight-trained again at night for an hour.”
Her transformation meant going from a size 23 in jeans to a size 27—and she embraced every inch of it.
“My boobs got bigger. And my butt got huge. It was crazy!” she laughed. “But it was amazing: I was so strong, like crazy strong.”
Training Three Times a Day, Every Day
Sweeney didn’t just bulk up—she became a boxer.
With a team of nutritionists, boxing coaches, and weight trainers behind her, the actress committed to a rigorous schedule that included multiple training sessions each day over a span of three and a half months. She filmed all of the film’s fight scenes in a single week, often leaving the set after 12-hour days only to head straight back to the gym for more training.
“I was getting pummeled,” she revealed at the Toronto International Film Festival. “They were holding ice packs to my face in between takes. I had some gnarly bruises after that.”
One brutal recreation of Christy Martin’s real-life fight with Laila Ali left her with a black eye that lasted days.
And yet, through the bruises and exhaustion, Sweeney felt empowered.
“It was incredible being able to completely embody such a powerful woman,” she said. “I felt even stronger. It was truly inspiring.”
A Diet Built for Bulk: Smucker’s, Chick-fil-A, and Milkshakes
Packing on 30 pounds wasn’t just about lifting heavy—it meant eating constantly.
“I had a nutritionist work with me… and we upped my calorie intake,” Sweeney said. “I ate a lot of Smucker’s, a lot of PB and J sandwiches, milkshakes, protein shakes—kind of just constantly always eating.”
She even admitted that Chick-fil-A made regular appearances in her meal plan.
“I was constantly burning it all off at the same time,” she added, noting the challenge of maintaining weight while staying active. “So keeping it all up was quite a challenge.”
From glam shoots to baggy sweatpants and elastic waistbands, Sweeney embraced the physical change with pride—not vanity.
From Dojo to Big Screen: A Lifelong Athlete
Long before she stepped into Christy Martin’s gloves, Sweeney had already developed a love for combat sports.
She grew up kickboxing and grappling in a dojo—often as the only girl—and trained from ages 13 to 19. “I fought all guys,” she recalled. “I liked to think that if sh– went down, I might be able to step up.”
That background gave her an edge in preparing for Christy, with director David Michôd noting, “I knew that she was already a fighter.”
He praised her work ethic on set, saying, “No matter how tough it was, she was like a ray of sunshine.”
Stripped of Glamour, Full of Grit
The film offers a raw, unfiltered look at Martin’s life: glory in the ring, and trauma at home. Ben Foster plays her abusive husband and trainer, adding further emotional weight to the story.
“This role isn’t light. It’s physically and emotionally demanding,” Sweeney told Deadline. “Christy Martin not only legitimized female boxing—she overcame gender stereotypes and fought through emotional, physical and financial abuse.”
Early screenings at TIFF (Toronto International Film Festival) received standing ovations, with many calling Sweeney’s performance Oscar-worthy.
But for the Emmy-nominated actress, the goal isn’t the trophy—it’s the story.
“I’m just glad that Christy’s story is out there,” she said. “Her journey is a testament to resilience, strength, and hope.”
The Power of Fully Embodying a Role
Hollywood is no stranger to actors transforming for roles, but Sweeney’s dedication stands out not just for the physical shift, but for how fully she immersed herself in Martin’s world.
From consuming thousands of calories daily to emotionally preparing for scenes of domestic violence, the actress left nothing on the table—or the canvas.
“She was really serious about her boxing,” Martin herself said in an interview with DailyMail. “She’s a perfectionist.”
Sweeney agreed: “Christy’s story isn’t a light one. But I love challenging myself.”
Why Her Transformation Matters
Sweeney’s transformation is part of a broader trend in Hollywood where female performers are increasingly taking on physically demanding roles once reserved for their male counterparts. But what makes this one notable is how unapologetically real it is.
She didn’t glamorize the process. She didn’t starve. She didn’t Photoshop her muscles.
She earned them.
She showed up—day after day, bruise after bruise—to tell the story of a woman who not only fought her opponents, but also the world around her.
And in doing so, Sweeney is pushing past the industry’s limiting standards of beauty and strength.
Christy hits theaters November 7, 2025, and is already being tipped as one of the most powerful performances of the year. For Sweeney, the black eyes, sweat, and bruises were all part of honoring the woman who inspired a generation.
“Her story changed lives,” she said. “I just hope mine does it justice.”
