As their fame grows, Hollywood's young stars appear to be shrinking by the second. Is it the pressure of hot careers -- and has their weight loss gone too far?

In 2004; July 2006

"I cannot make myself go to the gym," the five-foot-seven star tells Us. "I find it tedious." Yet Knightley's super-slim figure -- estimated to be 100 pounds by The Hamptons Diet author Dr. Fred Pescatore -- has some fans concerned. "She has a seriously controlled attitude toward her food," a pal says, adding that the actress, 21, usually subsists on fat-free, water-based food like melon or raw vegetables. "She's not letting herself eat the things she used to eat, like chips or big bowls of pasta." But London trainer Richard Smedley, who helped Knightley get fit for King Arthur, tells Us, "Of all the people who have had eating disorders, I really don't think Keira is one of them. She isn't into that Hollywood thin image."