But when it came to prepping for the new flick Adrift she was especially disciplined.
Speaking with The Times, the 26-year-old opened up about the rigorous eating regime she followed to play Tami Oldham – a woman who finds herself stranded at sea alongside her injured fiancé.
“For the last two weeks I had a can of salmon, some steamed broccoli and two egg yolks every day – 350 calories,” she said. “It was f**king miserable.”
Not only did the restrictive diet leave her insanely hungry, it messed with her sleeping habits too.
“I can’t sleep when I’m hungry so I would have a glass of wine to basically pass the f**k out,” she explained.
But this wasn’t the only physical challenge she faced during production. As most of the movie was filmed on open waters, Shailene and her co-star Sam Claflin battled constant seasickness.
“We were holding each other’s hair back,” Sam admitted in an interview with PEOPLE. “It was the best way to kind of get to know someone. When you see someone with sick around their mouth it’s bizarrely a great opportunity to break the ice.”