It seems apparent to the casual observer that only the human animal has the desire or understanding to cook his food. While it is true that domestic dogs and cats and other pets will eat cooked food given to them by human keepers, there is no other animal that routinely attempts to cook its food. This undoubtedly comes down to intelligence and the understanding of fire or heat, and could be dismissed as an obviously absurd statement that warrants no further consideration. But consider the question in another way. Why do humans feel the need to cook their food, when it could be perfectly possible, even advantageous, for them to eat it raw? In fact, save for a few cases, raw foods appear unpalatable to the average man if of animal origin. This question deserves consideration because along with other higher functions such as language, music and art, the comfort derived through cooking food is something that differentiates man from animal.
Let us consider the consumption of meat. Most predators are equipped with sharp claws, teeth or talons that allow the ripping of raw flesh in chunks and the consumption of that food whole with little time for chewing. The digestive juices of the stomach then are required to hydrolyse the peptide bonds of the amino acids and provide the creature with suitable nitrogen compounds amongst the skin, bones and other hard to digest components ingested. In contrast, the human animal begins digestion of meat some minutes before placing it in the mouth by applying heat, which denature the peptide bonds and tenderise the flesh. Following this the meat is often flavoured with sauce or additional food and then slowly chewed into small piece, thus supplying the stomach with pre-digested protein. In the case of fish, many of the bones, fins, innards and other non appealing parts are first removed, thus saving the digestive system the work of breaking down tough sinuous non-nutritious components.
While cooking meat to denature the proteins holds and advantage over eating the flesh raw in terms of digestive time, cooking can have quite different effects on other foods. Cooking vegetables holds the advantage of breaking down the cellulose cell walls of the plant cells, thus increasing the chance of those chemicals being absorbed when consumed. Lightly cooking tomatoes for example releases the carotenoids they contain which would otherwise not be available as nutrients to the consumer. Broccoli too contains beneficial chemicals that can be released from their cellular prison through application of heat, to enable absorption. In fact, cooking has added many plants that would otherwise be unavailable for consumption to the list of possible foods consumed by humans. Cooking can denature poisons and toxins present if foods, such as during the fermentation of soy products. In addition, hard to digest foods such as lentils and beans that would ordinarily be indigestible for humans, become good sources of protein and energy when their structure is denatured with heat.
However, when certain foods are heated more intensely, chemical components are altered causing a general loss of nutritional quality. Heating oil for example causes changes to the fatty acids, with polyunsaturated fatty acids being particularly susceptible on account of their structure. This leads to the production of rancid chemically altered oils that can have quite deleterious effects on health. Cooking fruits in high heat can also cause caramelisation of the sugars with the production of potentially problematic aromatic chemicals that can cause long-term ill health. However, despite this deleterious effects to foods, humans often create products from both heated oil and sugar and enjoy their consumption. It stands to reason therefore that the heating and cooking of food is not performed always to provide more readily available nutrients. Indeed, while the boiling and steaming of raw plant foods and meat can provide nutritional benefits, more intense and longer cooking is detrimental to nutritional quality.
Tea is another food that is cooked prior to consumption by humans. In the case of tea, the leaves are first fermented or steamed to breakdown the cellular structures. This process results in the production of black and green tea, respectively. The refreshment derived from a cup of tea after a period of exposure to cold or damp, cannot be explained by the nutrient content of the cup, as cold tea would not provide the same levels of satisfaction. Likewise the heat alone cannot explain the physically restorative properties of the tea that cannot be obtained from other hot drinks such as coffee. Tea is held in very high regard by certain practicing spiritually enlightened individuals, who claim it has the ability to increase the energy flow in the body known as chi. While undoubtedly the camellia sinensis plant provides nutrients to herbivores that graze its leaves, the comfort and emotional restoration it provides after heating is purely a human experience.
The fact that in some cases nutrient content of food is increased by cooking, but in others the nutrient content of food is decreased, logically suggests that the reason for cooking food is not to provide increased nutritional quality. Historical records and archaeological findings suggest that humans have cooked food for as long as they have existed on this planet. Yet there is no recorded evidence of the cooking of foods by the animals we are told are our closest ‘ancestors’. The obvious conclusion is that cooking food is a uniquely human endeavour and something that along with music and art defines our spirit. Like a piece of quality music, it is hard to philosophise why a hot cup of tea provides the comfort to the soul. And like a piece of fine art, it is difficult to conceptualise just why something cooked tastes better than its raw components. The sociable nature of cooking and eating too suggests that hot food is more about feeding the soul, than feeding the physical structure.