The difference between red meat and white meat varies, depending on who is providing the information. As a general rule, people use the term "white meat" to refer to meats that are pale before they are cooked, such as poultry, pork, and fish. Red meat, on the other hand, is meat that is distinctively red before cooking, as is the case with beef and lamb. The terms "white" and "dark" meat are also used to describe two different types of meat in a single animal, most commonly in the poultry industry.
Some people say that red meat is from mammals, while white meat is from other animals. Others create a third category for game. It is also not uncommon to see birds with a high concentration of dark meat like ducks and geese categorized as "red meat," despite the fact that their meat is pale before cooking. The confusion over the types of meat can be frustrating for consumers, especially when they read about things like a greater risk of cancer associated with red meat, as they may not know which meats are being referred to.
One way to think about the division between red meat and white meat is flavor. White meats tend to be more bland, as is the case with both chicken and pork, while red meats have a more intense animal flavor. Red meats are red because they have a higher concentration of myoglobin, a substance that helps the muscles utilize oxygen more effectively. Myoglobin creates a distinctive dark color, and it also allows muscles to be used for sustained, extensive activity like standing and walking.
In the world of poultry, dark meat also has a higher concentration of myoglobin, because it comes from parts of the body that have more muscular development, like the wings and legs. White meat in places like the breast is less muscular, designed for brief bursts of power rather than prolonged work. It could be said that red meat is for regular daily use, while white meat is intended for quick responses which are not sustained for very long. This difference is easier to pin down, because meats can clearly be categorized as having either slow twitch muscles designed for prolonged use or fast twitch reflex muscles.
When it comes to health risks, the differences between "colors" of meat appear to be primarily related to the myoglobin and fat content. Some studies have suggested that myoglobin may play an as-yet not understood role in the body that could increase the risks of cancer, and the fats associated with red meat are definite health risks. White meats are typically leaner, which is one of the reasons they have traditionally been touted as healthier.