How does Madonna, at the age of 50, manage to look as fit as she does? Is it that she maintains a monklike diet? Follows a punishing exercise regime? Takes horse pills? All of the above? Not even close, her friend Gwyneth Paltrow says. In the July issue of Bazaar, Paltrow reveals the super-freaky secret to Madge's eternal youth.

She’s so physically beautiful and fit, it’s just crazy. I think part of the reason she looks so good is that she’s always striving for more knowledge. She’s a very interested woman.

Emphasis ours, because, otherwise, you might not notice that Gwyneth just totally gave away the secret to Hollywood hotness. Looking back now, we feel really dumb for being so oblivious. What did we think Matthew McConaughey's six-pack was made of? Or Angelina Jolie's lips? Or Demi Moore? Now we know: It's BRAINS! Damn, we should have known. We had actually noticed that on days we strive for knowledge, our calves feel a little achy and our butts get a wee bit firmer. But then we sit down and read Us Weekly, and it all turns back to flab.

Gwyneth: I May Force Myself to Get Pregnant Again [Us]