Matthew McConaughey's Extreme Weight Loss Has Caused 'Body Soreness'

By Stephen M. Silverman

11/29/2012 at 10:55 AM EST

Seen a photo of a rail-thin Matthew McConaughey recently? The actor, who has significantly slimmed down for a new movie role, says there's nothing to worry about.

"I feel fine. I really do," McConaughey, 43, tells The Daily Beast in a new interview, noting that his regime to lose nearly 40 lbs. from his 183-lb. frame was healthy, disciplined and well thought-out.

Nevertheless, that hasn't quelled chatter over the meaty matter of his dramatic weight loss for Dallas Buyers Club, in which he plays the real-life Ron Woodruff, who contracted HIV.

"I'm eating fresh fish. I'm just eating small amounts. I'm not being starved," says the actor, who also says he's sleeping well. "If anything, it's as much a spiritual journey as it is physical."

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Though his body's "fine," McConaughey says, "Everything has shrunk quite a bit. ... I don't have the leverage I used to. I have body soreness. ... [But] I'm as healthy as can be. My blood pressure, everything's fine."

Getting back to his normal weight, McConaughey points out, will take special care, or else he may risk a form of diabetes.

"You can't just start eating cheeseburgers and ice cream," the actor, who just nabbed two Independent Spirit Award nominations for roles in Magic Mike and Killer Joe, says. "Your body will go into shock."