Why is hot food important?
Hot food is important because it changes the food we eat. It has both historical and current significance.
The heat created during cooking is an agent of a chemical process called denaturation that changes the proteins in food, breaking down the molecules and altering their physical and chemical properties. Depending on the proteins cooked, this causes them to decrease in solubility or hydrophobic proteins to bind together to reduce the total area exposed to water. Denaturation affects the feel, taste, appearance and smell of food. A fried egg clearly shows denaturation and is a good example: white, liquid egg white (albumen) reaches a fixed consistency and turns opaque white when heated. As with many denatured proteins, the process cannot be reversed, meaning you cannot go back to the raw egg once it has cooled.
The denaturing process may be desirable because foods look, taste, and smell better when cooked, and the chemical changes may allow the creation of new foods such as meringue. To create a meringue, you need to break the chemical bonds between the egg molecules so they can recombine with the sugar molecules.
Cooking has another function because it also kills bacteria, parasites and viruses, making the food we eat safer. Bacteria such as Salmonella and E. Coli can cause serious illness in humans and, at the very least, cause an unpleasant stomach upset. In the worst case it can cause death. Children, the elderly, pregnant women, and immunocompromised individuals are at higher risk for serious illness from foodborne illness, and thorough cooking helps make food safer for them.
The heating process also softens food and makes it easier to digest. Cooked foods contain the same number of calories as raw foods, but require less energy to digest. Cooking makes starches more digestible. Starches are not soluble in water, so they must be heated to break them down (a process called gelatinization). When they are broken down, it is easier for them to reach the digestive juices in the stomach. Raw starchy foods are also generally unappetizing and tough (think raw potatoes) and cooking them makes them tasty.
Hot food also helps us warm up and is comforting. It is much better to come home in winter with a warm stew than to come home with a bunch of raw vegetables.
We prefer to have hot food as part of our diet. That’s not to say that raw food doesn’t play a role as well, it’s just that humans like a mix of both and it benefits us to do this.
The ability to heat food was one of the things that helped humanity evolve into the dominant species it is today. Cooking allowed us to digest some types of food more easily and we were able to eliminate bacteria and parasites, giving us safer food. Without the discovery of fire and the ability to cook food, we would not be in the position we are in now, and this means that the addition of hot foods to the human diet was a very important step forward in our evolution.