Sydney Sweeney, a well-known American actress, faced an unusual challenge last year: to prepare for filming a biographical drama about former boxing champion Christy Martin, she had to gain 13 kilograms. To do so, Sweeney completely overhauled her diet and training regimen to match her character’s physique. Once filming wrapped, she was faced with a new task—losing the extra weight in just seven weeks to get ready for her next role.
In an interview, Sweeney admitted that gaining weight was no easy feat. She consumed large amounts of protein daily, drank protein shakes, and significantly increased her caloric intake. Training became a staple of her daily routine: strength workouts in the morning, intense kickboxing in the afternoon, and another weight session in the evening. This regimen helped her quickly build the necessary muscle mass, but after the project ended, she had to urgently change her approach.
The road to a new role
When filming was over, Sweeney decided to eliminate protein supplements and creatine, and also reduced strength training. She focused instead on cardio and a balanced diet to speed up fat loss. According to the actress, the first changes were noticeable after just two weeks: her muscle mass decreased and her weight began to drop. Sweeney noted that achieving results required maximum discipline and strict adherence to her plan.
For seven weeks, the actress followed a strict regimen: daily cardio workouts, no heavy foods, and constant monitoring of her diet. She emphasizes that this approach requires not only physical but also psychological resilience. Sweeney has been involved in sports since childhood, which she says helped her quickly adapt to the new routine and regain her previous form.
Changes in Appearance
In addition to noticeable weight loss, Sweeney also changed her style. For the role of Christy Martin, she had to give up her usual long blonde hair — in the film, she appears with short, dark, curly hair. In her next project, where she will play the lead, audiences will see her with natural makeup and medium-length chestnut hair. These transformations highlight how seriously Sweeney approaches each role and her willingness to change for the sake of her art.
The actress does not hide that such drastic changes in weight and appearance require immense effort and self-control. She admits that she would not recommend others attempt similar experiments without professional supervision, since sudden weight fluctuations can negatively affect one’s health. Nevertheless, Sweeney’s experience became an important milestone in her career and proved that, with the right approach and strong motivation, it is possible to achieve impressive results in a short period.
Discipline and Sports
Sweeney notes that her love of sports and an active lifestyle has been the key factor in her success. From an early age, she was involved in various physical activities, which helped her build endurance and quickly adapt to new challenges. The actress believes that her athletic background enabled her not only to gain but also to lose weight without serious consequences for her health.
In an interview, she emphasized that she does not consider her experience easy. Every day required her maximum commitment and self-discipline. Sweeney advises anyone facing the need to change their weight to approach it mindfully, and not to chase quick results at the expense of their health.
In case you didn’t know, Sydney Sweeney is one of the most in-demand young actresses in Hollywood, best known for her roles in popular TV series and films. Over recent years, she has repeatedly impressed audiences with her transformations and professionalism. Her approach to her work is marked by total dedication and attention to detail, making each of her roles memorable. In 2025, Sweeney continues to actively act and participate in major film projects, showcasing not only her acting talent but also incredible willpower.
