Pet food is a big business, worth over 25 million dollars annually in the United States alone. Owners choose what to feed their pets based on marketing, personal views and their pets' preferences. Current trends show that owners like to provide their pets with the same kind of foods they themselves might consume—high-quality meat and organic produce—but this is not necessary for pets' health nor is it environmentally sustainable. Dog and cat foods, for example, typically contain 30 to 60 per cent protein, much of it derived from animal sources, which require a lot of land, water and food to raise. Since meat is already being produced for human consumption, the best thing to feed pets is the by-product of this process. Many parts of animals that humans tend not to eat are good-quality and appealing sources of nutrition for pets.