Many people prefer one color of turkey or chicken meat to the other, but why is dark meat dark and white meat white? The difference between the colors’ origins comes down to more than just superficial coloring. It has to do with chemistry of the turkey’s muscle.
Skeletal muscles, which are connected by tendons, can be divided into two separate types: Type 1 or slow twitch fibers and Type 2 or fast twitch fibers. The former are meant for extended activities that will require lots of endurance. When a turkey is walking around, it’s using slow twitch fibers. Their dense network of capillaries and stored fat are aided by myoglobin. It’s this myoglobin that gives dark meat its namesake. It’s also why dark meat is higher in fat as well as iron. When a turkey takes to flight, however briefly, its type 2 fibers are at work. What these muscles lack for endurance they make up for in being able to produce short-bursts of action. The glycogen in these muscles doesn’t have nearly as much myoglobin, which explains their lack of dark color. Despite their differences, nutritionally, it’s basically a toss-up between these two types of meat. While dark meat does have twice the fat, despite the fact that they have almost the exact same amount of calories, it also has more iron, vitamins B6 and B12.