One of the main differences between white meat and dark meat is the amount of myoglobin in the muscles. Myoglobin is a protein found in skeletal muscle that plays a significant role in oxygen storage. It also impacts the color of the meat.
There's no reason why you can't substitute white meat for dark meat in an entree, or vice versa. However, due to the differences in the contents of white meat vs. dark meat, you will likely have to adjust your cooking times to fit the type of meat you’re using.
How healthy your chicken dish is will depend on how the chicken is cooked, but there is a difference in the nutritional value of white meat vs. dark meat chicken. Skinless chicken breast, for example, is lower in calories and fat than the dark meat of a chicken thigh or drumstick.
Many people have a specific preference for either white meat or dark meat. Typically, dark meat is seen as more flavorful than white meat because of its high fat content. Dark meat is also juicier since white meat can easily be overcooked.