Meat is the oldest and most persistent protein source in human history, with paleontological evidence suggesting that early hunter-gatherers relied on the organized hunting of large animals like bison and deer to survive. This dietary foundation shifted dramatically during the Neolithic Revolution, approximately 11,000 years ago, when humans began domesticating vertebrates such as goats, sheep, pigs, and cattle. The domestication of these animals allowed for the systematic production of meat and the selective breeding of animals to improve meat production, transforming meat from a sporadic hunt into a reliable food source. The word meat itself comes from the Old English word meaning food in general, but modern usage restricts it to skeletal muscle with its associated fat and connective tissue, sometimes including offal like liver and kidney. Without preservation, bacteria and fungi decompose unprocessed meat within hours or days, making the development of cooking and curing techniques essential for human survival and cultural development.
The Science of Muscle and Fat
The biochemical composition of meat varies in complex ways depending on the species, breed, sex, age, and plane of nutrition of the animal. Adult mammalian muscle consists of roughly 75 percent water, 19 percent protein, 2.5 percent intramuscular fat, 1.2 percent carbohydrates, and 2.3 percent other soluble substances. Muscle proteins are either soluble in water, known as sarcoplasmic proteins, or in concentrated salt solutions, known as myofibrillar proteins. The two most abundant myofibrillar proteins, myosin and actin, form the muscle's overall structure and enable it to deliver power, consuming adenosine triphosphate in the process. Fat in meat can be either adipose tissue, used by the animal to store energy, or intramuscular fat, which contains phospholipids and cholesterol. The fat content of meat varies widely with the species and breed of animal, the way in which the animal was raised, what it was fed, the part of the body, and the methods of butchering and cooking. Wild animals such as deer are leaner than farm animals, leading those concerned about fat content to choose game such as venison.The Industrial Meat Machine
In the postwar period, governments gave farmers guaranteed prices to increase animal production, raising output at the cost of increased inputs such as animal feed and veterinary medicines, as well as of animal disease and environmental pollution. In 1966, the United States, the United Kingdom, and other industrialized nations began factory farming of beef and dairy cattle and domestic pigs. Intensive animal farming became globalized in the later years of the 20th century, replacing traditional stock rearing in countries around the world. By 1990, intensive animal farming accounted for 30 percent of world meat production, and by 2005, this had risen to 40 percent. Modern agriculture employs techniques such as progeny testing to speed selective breeding, allowing the rapid acquisition of the qualities desired by meat producers. For instance, in the wake of well-publicized health concerns associated with saturated fats in the 1980s, the fat content of United Kingdom beef, pork, and lamb fell from 20 to 26 percent to 4 to 8 percent within a few decades, due to both selective breeding for leanness and changed methods of butchery.