The modern world offers a lot of options that were never available to humans of the past. However, as with most modern advances in the name of convenience, there are often unacknowledged reasons why the humans of the past did things differently that had nothing to do with their lack of access to modern technology and transportation.
Diet is one of the areas where modern humans have seen some of the biggest changes compared to their ancestors. One of the biggest changes that has occurred is that now the average first world consumer has access to fresh fruit and vegetables year round. A person can walk into most restaurants and get a salad loaded with lettuce and other cold, crisp veggies any time the urge strikes him or her. The question that must be asked, then, is this a positive change, and if it isn’t, why is that the case? The goal of this entry is to explore some of the underlying mechanisms of the body that are affected by the temperature of the food that is consumed and how it can affect how an individual feels as well as why these changes may have less of an impact on people who live in the developed world.
Before the conversation gets too deeply into the theory, a quick history lesson is in order. Recent archaeological evidence shows a strong connection between the widespread adoption of cooking food before consumption and the development of civilization. While this idea may seem a bit odd on its face, an examination of how heat affects food and how the digestion works may clarify how these two concepts are linked and why.
When heat is added to any substance, it speeds up any chemical reactions that may be occurring inside of it. This includes processes like the breaking down of organic matter. Organic materials require a constant supply of nutrients, which is often provided by the organism that they are a part of. Whether it is a piece of fruit, a body part, or a complete life form, once the body is no longer able to provide constant maintenance to the cells that make up the the aforementioned part, cell death begins and the structure starts to break down. Heat increases this process and cold slows it down. This is why humans freeze foods to prevent spoiling, but the reverse is also true. Adding heat from an outside source will increase the breakdown of the organic material into its component molecules and possibly down to the atoms themselves, depending on the heat and substance involved. This is the underlying process in everything from composting to the human digestion (which is a comparison that will come up again later).
The human digestive system is basically composed of three components – the stomach, the small intestine, and the large intestine (there are numerous other organs involved to varying degrees, but most of the actual breakdown of food is done in these three, so for the purpose of the article, the focus will be on these.) Each aspect of the digestion has a separate job and serves a very specific purpose. As food works its way through these three parts of the system, it is exposed to different chemical and physical forces which, when combined, make up the process of breaking down food into the parts the human body can use as well as eliminating those elements that could be considered nutritionally useless (like fiber) or harmful (like bacteria or parasites).
The first part of the digestive system is the stomach. This is the body’s internal equivalent of a cooking fire, but a more appropriate comparison might be to an acid bath. The reason for this is because the stomach works primarily through dousing anything that has been consumed with a very strong acid that is used predominately to break down proteins, thicker plant materials, and to kill any bacteria or other foreign organisms that might have been in the food. Due to this process being predominately chemical in nature, heat has less impact on this step than the two that follow it, but as mentioned before, heat will speed up any chemical reaction, so when dealing with colder substances, the stomach will be less efficient in breaking these foods down before they move on to the next step of the digestive process.
Most of what is traditionally thought of as digestion actually takes place in the second part of the body involved in the break down of food – the small intestine. This is where the earlier compost comparison comes into play. The small intestine functions much like composting in the way that food is broken down. Substances from other organs like enzymes and bile play a part, but the main actors involved are the natural bacteria which live inside the intestine. As the food is transported from the stomach and through the small intestine, the native bacteria reduce it into the components the body needs and transports those nutrients into the blood stream. This includes carbohydrates, fats, certain vitamins, and proteins. Other substances such as fiber continue to travel through the length of the small intestine and are delivered to the large intestine for the final phase of digestion.
The large intestine’s function is similar to a sewage reclamation plant. This is the point in the digestive process where as much water as possible is reclaimed from the mostly digested food material, including any water soluble nutrients (such as B and C vitamins) and metabolic waste processes are sent for elimination from the body. There are still some bacteria involved, but for the most part, what is left in this part of the body is predominately waste. Consuming an overabundance of colder foods can impair this function of the body, however, as cold and undercooked foods are often not broken down completely and these food remnants can serve as breeding grounds for bacteria (which upsets the internal balance) or by creating blockages (which leads to toxins building up as they cannot be eliminated).
So how does heat, both in the food itself and in the environment, become a factor in the digestive process? As mentioned above, heat speeds up chemical reactions, and at its most basic level, digestion is a chemical process. Some aspects of this are more complex (such as how bacteria breaks down food in the intestines) while others are more direct (acid breaking apart protein bonds), but all of them can be effected by heat or a lack thereof. When it comes to cooked versus raw foods, the effect of heat is apparent, and this is the basis of the theory that cooking food and cultural advancement go hand in hand. By cooking food before consumption, the breakdown of food into its component nutrients has already begun. This frees up energy that would have been previously used to in digestion and allows it to be placed into other aspects of life. It also increases the amount of the foodstuff that is usable, as the digestion may not have generated enough heat on its own to breakdown certain edible substances, especially some of the heartier vegetable matter such as roots and tubers. For humanity, this excess energy went into greater cerebral development, which over time lead to greater exploration and development of the sciences, art, and culture.
Conversely, it means that foods that are less broken down require more energy to digest. For some foods, like berries, this can be a relatively minor change as they are mostly sugars and can be broken down fairly easily, but for more complex foods like meats and vegetables, the lack of cooking may make them harder to digest or render them completely unusable to the body. In the case of meats and other raw vegetables, it also increases the number of harmful bacteria and other substances that the immune system will then have to deal with, further decreasing the available resources as they are shifted to the digestion.
The environmental climate is then the background upon which this process plays out and, as such, often plays an important role in determining how much energy is available to the digestion to do what it needs. One of the most energy consuming functions of the body is temperature regulation. When the weather is cold outside, there are certain mechanisms that the body will engage in order to regulate the core body temperature. Muscles will flex and relax to generate heat, circulation will change based on where it the blood is most needed to protect vital organs, and the amount of energy available for more voluntary acts will be limited to what is left over. This cold also reduces the efficiency of the digestion by making the body need to expend more effort to break down food as well as slowing the reactions that are taking place. If heated food is consumed, however, this adds heat to the system, which reduces the impact of the cold outside.
A warm environment, in comparison, often aids in the breakdown of foods in the digestion, but can also speed the spoiling of foods, so that cooking them aids the body by reducing the number of harmful bacteria that may be present in certain foods. This does mean, however, that foods can be too hot, and can actually contribute to dehydration and other discomforts by overheating the body. Because of this factor, foods are often cooked to a lesser degree, and more raw foods are consumed, but due to the greater amount of heat in the environment, this is less disruptive to the digestion than it would be in colder weather.
There are also two other factors that should be addressed before moving on. The first is that for much of human history, people were limited to the foods that were native to their location. Animals and especially plants that evolved in warmer climates were often far easier to consume than the native species of colder climates. Mostly this was because those species didn’t have to develop any adaptations to deal with more inhospitable climates. Whereas humans primarily developed technologies to adapt to different climates (clothing, fire, shelter), plants and animals often evolved structures such as thicker shells and smaller leaves in plants and different fat to muscle ratios in animals to compensate. This meant that the foods derived from these often require more effort to utilize and so cooking them transitioned from a helpful act to a necessary one.
The second thing that should be mentioned is overcooking. Now, it’s been stressed over and over that adding heat to food speeds its breakdown and makes it nutrients more available, but if a food is overcooked, it is possible for the heat to consume all of the nutritional value and just leave relatively useless matter behind. Basically, if something has been cooked to the point where it cannot spoil, then there is nothing left to breakdown. Think of the meat that has been cooked down to charcoal or vegetables that have had all the color boiled out of them – at that point, there is nothing left for the body to use. So, let that be a reminder, like most things involved in health, it is possible to go too much one way or another, so moderation is key.
So now that the mechanisms of digestion have been explained a little, it is time to look at exactly how to choose the proper food to eat based on the time of year and the weather outside. One of the theoretical bases of Chinese medicine that has no equivalent in the mainstream Western model is the idea that foods have inherent temperature changing properties. A gross simplification of this idea would be to say that in TCM (Traditional Chinese Medicine), the knowledge of the cook and the doctor are combined into a whole philosophy. In other words, the categories that are used to differentiate the effects of medicinal herbs are also applied to food. These categories include flavors, temperature, and systems affected by the substance. This information is then used to decide which food or herb would be appropriate in which cases as well as revealing what side effects should be expected when those same items might have when used inappropriately. For example, the flavor ‘acrid’ is often used to describe foods that have a dispersing effect, and foods that have this characteristic are often warm or hot in temperature. This includes foods like peppers, which can raise the body’s temperature and induce sweating (heating the body and dispersing stagnation). When a person is cold and has trouble sweating in warmer temperatures, this might be a food you would use. However, in colder temperatures, that may not be the case, as sweating opens the pores and, especially in windy climates, the pores being open may allow more cold to seep into the system, worsening any symptoms.
This framework allows a practitioner to choose foods based on the needs of the individual, but also allows for factoring in elements such as climate. As has been mentioned above, whatever a person consumes requires energy in order for it to be broken down and the environment can help supply some of the energy needed for digestion. Due to this, dietary recommendations in the summer are very different from recommendations in the winter. A person’s energy is also a vital consideration in choosing which foods they might want to eat at certain times of the year. One of the reasons why this type of approach to food isn’t as prevalent as it might be comes from the simple fact that humans (especially in the first world) are not as physically active as they once were.
Before, if an individual had a job that required a lot of physical labor, a diet high in proteins, fats, and complex carbohydrates would have been necessary in order to have the energy needed to get through the day. By cooking these kinds of foods, their nutrients were more available and that person had even more energy available. In comparison, if a person has a more sedentary lifestyle, he or she may not be as aware of his or her own nutritional shortcomings, since life doesn’t require the same amount of fuel. This is especially true since, in the modern world, easily available simple carbohydrates which provide fuel for the brain are plentiful as are stimulants which mask the amount of physical fatigue an individual might otherwise experience.
In fact, the preponderance of simple carbohydrates in the diet has led to increased weight gain among some of those more sedentary individuals which then pushes them to consume more foods like salads and raw veggies. Unfortunately, especially in winter, these cold foods further cool the body, draining energy and increasing fatigue levels, pushing people to consume even more processed foods, sugars, and stimulants, creating a self-perpetuating cycle.
So what should a person eat and when? During the colder months, the diet should contain more warm foods, preferably broken down to some degree in a liquid or broth, or cooked to a maximum tenderness. These would be your soups, broths, and animal and poultry meats. A focus should be placed on fat levels and nutritional density. For vegetables, tubers, roots, and things that grow under the ground will provide the highest levels of nutrition and energy per serving.
In the warmer months, lighter foods can be consumed. This is the time for leafy vegetables, fruits, and fruits and poultry. Melons, salads, and sushi are more appropriate for these seasons and climates, and the cooling effect of the food will also help negate the increased heat of the environment. (Also note that these foods also have a high water content, so they aid in hydration as well.)
That’s not to say that these are hard and fast rules, just general guidelines. If these factors are kept in mind, there is no reason a person still can’t indulge in non-seasonal foods, just that they might have to make a few adjustments to how they eat them. Steaming vegetables and fruit is an excellent way to make them more winter-friendly, as is grilling. Proper spicing can also reduce the impact of cold foods in winter and hot foods in the summer. Also, and as silly as this sounds, it works – makes sure the food is completely chewed before swallowing. The smaller chunks are easier for the body to break down, and there is an enzyme in the saliva that helps jump start the digestion process. Finally, stay physically active, especially with activities that involve moving the torso (for all the belly-dancers out there, keep it up). When the accessory abdominal muscles are engaged (the obliques and transverses, mainly), the contractions aid in the movement of food through the intestines and reduce the amount of work required by the smooth muscles lining those organs. This means less overall energy is required for digestion as well as aiding in posture (poor posture being another factor that can impede digestion).
So hopefully people found this information helpful and if there are any questions, please feel free to email me. These tips should help give everyone some aid in staying more active and being less tired this winter, as well as letting them get the most out of their holiday feasts. Till next time, be safe and be healthy.