This Q&A is part of Us Weekly’s 2015 Holiday Movie Preview.

It’s not easy being lean. Based on the true tale that inspired Moby Dick, Ron Howard’s In the Heart of the Sea (in theaters Dec. 11) details a harrowing whale encounter that leaves Chris Hemsworth and his costars (including Cillian Murphy and Tom Holland) shipwrecked and starving. The Oscar-winning director tells Us Weekly about the cast’s crazy diet, what advice he got from Tom Hanks, and his possible future collaboration with daughter Bryce Dallas Howard.

Us Weekly: Chris Hemsworth brought the In the Heart of the Sea script to you. What about the story hooked you?

Ron Howard: I had been thinking about different kinds of movies in the ocean for a long time, which — by the way, I don’t like the ocean! People would think that I must have a boat or something. I never do anything recreational out there! I’m not scared of it. It’s just not a fun place to me. It’s kind of a foreboding place, and I think that’s what’s always attracted me to this story. It’s entirely about the unexpected, and it was a great performance opportunity for Chris and an ensemble of great young actors.

Us: What lengths did Hemsworth and the other actors go to portray their shipwrecked characters?

RH: Not only were they shooting, but they had to meet with trainers and dietitians, do workouts, and reduce their calories starting at 1500 a day and down to 5 or 600 a day. They had pathetic little snacks! And this is all while they were out on the actual ocean, exerting a hell of a lot of energy, and yet they were suffering in this way. I think they all were doing everything they could as actors to use their controlled starvation to understand what the abject starvation their characters faced was like.

Us: And you called Tom Hanks for advice!

RH: I did! He’s had to lose weight for two roles before — once for Philadelphia and once for Castaway. He told me, “The one advantage that your guys are going to have is that they’re together doing it as a unit. That’s bound to help because doing it alone is so challenging to keep up that discipline and denial.” But he also warned of doing it in the most healthy way and under supervision.

Us: Were you fasting along in solidarity? Or were you over there guiltily eating your pizza in a corner?

RH: I didn’t fast, but I definitely lost weight on the movie! [laughs] And when a crew member or someone had a pastry or a meat pie, I tried to make sure that they would go to the other side of the ship to eat it. The problem was, it wasn’t that big of a ship.

Us: Any future plans to direct your daughter?

RH: I would love it! We don’t have a script currently that we’re working on. You know, her directing career is beginning to take shape, so our collaboration could come in a lot of different ways — including her casting me in a movie! She’s got a great love of the medium and a tremendous story mind. I’d be lucky to work with her.

Us: Which of your projects are you most excited to show your grandkids when they’re a bit older?

RH: I have a grandson who’s both really interested in art and all things mechanical, so I think he’ll get a huge kick out of Apollo 13 someday. And I think my granddaughters will enjoy Splash. I don’t think they’ve seen The Grinch yet. My daughter is very careful about holding back the TV and video addiction, so they haven’t seen much yet.

Us: And we have to ask: Will we see a fifth season of Arrested Development anytime soon?

RH: We’re working on it! [Executive Producer] Mitch Hurwitz and a small group of writers are exploring it. So much of it has to do with how incredibly successful our entire cast has become. And so the viability of getting everybody together is more challenging by the month. But I think it’s everybody’s intention to try to find a way to do it, and I’d be very disappointed if we didn’t. Fans keep calling for it. Netflix is very supportive. And the cast and crew definitely wants it!