Why is white meat white and dark meat dark?
What is the difference between white- and dark-meat chicken? In other words, what makes white meat white and dark meat dark?
White meat is white because of the chicken's chronic lack of exercise, something to think about next time you're about to curl up in front of the TV for another I Dream of Jeannie rerun. Dark meat, which avian myologists (bird muscle scientists) refer to as "red muscle," is used for sustained activity--chiefly walking, in the case of a chicken. The dark color comes from a chemical compound in the muscle called myoglobin, which plays a key role in oxygen transport. White muscle, in contrast, is suitable only for short, ineffectual bursts of activity such as, for chickens, flying. That's why the chicken's leg meat and thigh meat are dark and its breast meat (which makes up the primary flight muscles) is white. Other birds more capable in the flight department, such as ducks and geese, have red muscle (and dark meat) throughout.
Muscle type is genetically determined, so we can forgive the chicken for thinking, Hey, exercise is futile! My breast is going to stay white no matter how many reps I do on the Nautilus! This is not true for humans, but I understand the feeling. Where's that remote?