CAMERON DIAZ: ‘RUNYON’ HER BUNS OFF

By the way, ladies . . . yoga’s not the real secret behind Cameron Diaz‘s rockhard buns and taut thighs! Lotsa fitness buffs huff and puff up steep Runyon Canyon in the Hollywood Hills — but dazzling Diaz passes them all at a dead run. Her over-theshoulder reply to a winded fan who yelled, “How do you make it to the top?” was: “I’ve been doing it for years . . . it’s the only thing that keeps my butt and legs in shape!”