After filming Ron Howard’s whaling epic, In the Heart of the Sea, Chris Hemsworth was a shell of his former hammer-wielding self. Last month, the Thor star tweeted out a photo to show just how much the 500-calorie-a-day diet changed his appearance. “Just tried a new diet/training program called Lost at Sea,” he wrote. “Wouldn’t recommend it.” Hemsworth spoke to Entertainment Weekly about the difficulty of the extreme dietary restrictions. “When you’re already starting off lean, it’s brutal to chew through that kind of weight. Every pound feels like a kilogram,” he said. “We kind of went insane, weighing ourselves every day. We all felt like a bunch of supermodels, trying to get down in weight for a show or something,” Hemsworth added. “That’s all we spoke about. You’ve got 15 burly blokes on the sea and all we talked about was our diet and who’d lost more weight and who’s looking really skinny. It’s ridiculous!”