Food Combining, Digestive Physiology and Optimal Digestion
The entire basis for our interaction with food is the process of digestion and absorption/assimilation. This is the physiological and biochemical process by which our bodies break down the foods we eat into small enough particles to be absorbed into the blood and lymphatic fluids which carry them to the cells for nourishment. It behooves us to have very efficient and effective digestion and absorption for this is the way we gain the necessary nutrition from the foods we consume. Also, incompletely digested foods tend to create an unhealthy, putrefactive environment (due to abnormal intestinal flora) in the intestines, especially the large intestine. THE WAY WE COMBINE CERTAIN TYPES OF FOODS WHEN WE EAT PLAYS AN IMPORTANT ROLE IN THE ABILITY OF OUR DIGESTIVE SYSTEMS TO COMPLETE DIGESTION AND ASSIMILATION EFFICIENTLY.
The Golden Rules of Food Combining
Lets look at the anatomy and physiology of digestion. Digestion is a sequence of biochemical breakdowns which must proceed in an orderly manner to operate optimally. The effectiveness and completeness of each step directly modulates the success or failure of the following steps.
Digestion of all foods actually begins in the mouth, where the teeth grind things into fine enough particles that the enzymes and juices secreted further on in the digestive sequence can mix thoroughly with the food pulp. As we have all heard from our parents "chewing thoroughly" is extremely important. Nothing should be swallowed which is not chewed to the consistency of a fluid and mixed thoroughly with saliva. This can take a whole lot of chewing for some foods!!!!! And it can make for slow eating, a talent not very common in our modern world. My father always said chew every bite 100 times. That may be over doing it a bit but try chewing foods to a fluid consistency for a week and you will get a feel for how long it takes to chew food thoroughly. Chewing well and eating slowly is not only good for digestion but helps with weight loss as well.
After the food is swallowed it goes to the stomach where protein digestion begins and is primarily completed by the hydrochloric acid, pepsin and gastin secreted there.
After passing out of the stomach it goes into the small intestine where all particles are broken down into the smallest size necessary for absorption into the blood and lymph system. The small intestine is approximately 22 feet long and the absorption of all foodstuffs occurs there. Whatever has not been absorbed then moves into a larger tube which is about four or five feet in length called the large intestine or colon. All that makes up the contents of the large intestine is cellulose fiber, undigested/unabsorbed food particles, both living and dead bacteria and other organisms from the intestinal flora population which exists in each of us (see section on the Human Microbiome), dead cells and a few chemical secretions coming from the intestinal tract itself. In the large intestine water is removed from this remaining food pulp and the solid fecal matter is then eliminated from the body. As you can see, the food undergoes a long journey from beginning to end ---- up to almost 30 feet in length and two or three days in time. Each type of foodstuff undergoes a different biochemical processing on this trip. Let's look at each one of the basic food constituents --- carbohydrates, proteins and fats --- and their biochemical breakdown.
The chemical aspect of carbohydrate breakdown begins in the mouth during chewing. When carbohydrate is present in the mouth the salivary gland secretes a digestive enzyme called ptyalin. This enzyme breaks large carbohydrate molecules down into smaller complex sugars. The enzyme ptyalin can only act effectively when it is in a strongly alkaline environment which our saliva provides because it is alkaline. If, however, we consume acidic foods (such as oranges, grapefruit, apples, peaches, vinegar or wine) with carbohydrates, this necessary alkaline environment is chemically altered and ptyalin cannot perform its necessary function of beginning carbohydrate breakdown. Hence, food combining rule #1: eat acids and starches at separate meals. This makes fruit a very poor dessert food for it has a high acid content. It is interesting to note that when pure proteins, fats, sugars and acid or sub-acid fruits are chewed no ptyalin is present in the saliva which mixes with these foods. Ptyalin is secreted only when carbohydrate is present in the mouth.
After being swallowed the food goes to the stomach where the gastric juices range from neutral to extremely acid, depending on the type of food eaten. The level of acidity in the stomach is regulated by the amount of hydrochloric acid secreted, but the actual digestion of the food contents takes place by the action of two enzymes: the first is pepsin, which acts upon proteins to break them down into small chains of their building blocks which are called amino acids; and , second, is lipase, which has a slight action on fats.
Pepsin (the protein digesting enzyme) can act chemically only in an acidic environment which is created when the stomach secretes hydrochloric acid. This acidic environment is neutralized by any alkaline foods or solutions added to the stomach. Low temperatures (such as when iced cold drinks are taken with or after a meal) retards or may even suspend the action of pepsin. If pepsin is given the wrong chemical environment it cannot breakdown proteins and their digestion is severely inhibited.
We know that carbohydrate digestion begins in the alkaline saliva of the mouth, and protein digestion occurs in the acidic juices of the stomach. When alkaline and acid are combined they neutralize each other and prevent the action of both ptyalin and pepsin. The two processes --- the digestion of carbohydrate and the digestion of protein --- do not occur simultaneously with great efficiency. As a result, the digestion of both the carbohydrate and the protein eaten at the same meal is significantly reduced.
Now we can understand the importance of food combining rule #2: eat protein foods and carbohydrate foods at separate meals. In other words, carbohydrate foods such as grains, beans, nuts, seeds potatoes, yams and winter squash should be eaten separately from the pure proteins such as meat, chicken, fish , eggs, milk, cheese and yogurt.
After remaining in the stomach for one to three hours the food enters the beginning of the small intestine (an area which is called the duodenum) --- here the final stages of digestion of both carbohydrate and protein take place. Upon entering the small intestine gastric secretions change the contents to an alkaline solution --- this is necessary because all of the enzymes which complete digestion in the small intestine must have an alkaline environment in order to perform their function. The pancreas does most of the work, secreting enzymes which complete the breakdown of both carbohydrate and protein into small enough particles that absorption can occur. Fats are emulsified or broken apart upon entering the small intestine by the bile secreted by the gall bladder and are further digested by lipase secreted by the pancreas. Some of the cells lining the upper and middle areas of the small intestine secrete digestive enzymes which help the pancreas in its function.
Now that digestion is complete the food travels the 23 feet of the small intestine while all the nutrients it contains are absorbed into the blood stream and lymphatic fluids. These two circulatory systems will now carry the nutrients to the cells for use as well as picking up waste products and delivering them to the channels of elimination from the body. After traversing the length of the small intestine the remaining unused waste contents enter the large intestine or colon. While the main function of this area of the gut is to reabsorb water from the contents, other interesting things occur here. Within the colon of all people live millions of tiny organisms (mostly bacteria) which breakdown and live off of what is left of our food after digestion and absorption are completed. There are two types of bacteria which may live in your colon --- let"s call them "friendly" and "unfriendly". The friendly ones are fermentative bacteria and the end products of their life processes are lactic acid and other harmless and even useful chemicals and vitamins. The unfriendly bacteria, on the other hand, putrefy the undigested proteins which results in a release of poisons such as indol, skatol, phenol and hydrogen sulfide. These toxins are passively absorbed into the bloodstream along with the water which is being pulled out of the food contents of the colon. When we eat in a manner which does not optimize digestion the unfriendly bacteria have more to live on and their population increases --- with this increase in numbers is a corresponding increase in the toxic byproducts resulting from putrefaction. This adds a heavier toxic load to the body tissues, blood and liver (which is the filtering organ for the blood). Proper food combining to maximize digestion cultivates a population of friendly bacteria in your colon which competes with the unfriendly bacteria and keeps them to a minimum. It is also important to note that a healthy population of friendly bacteria synthesize a nutritionally significant amount of B-vitamins which are passively absorbed into your blood. These beneficial bacteria and other gut organisms and yeasts have recently been shown to be beneficial to health in numerous ways (more on this later as its a very important topic) and it behooves us to cultivate a healthy intestinal flora. Taking a daily probiotic helps to boost this population as well.
When anti-biotics and some anti-bacterial herbs are taken large nuumbers of the bacteria in the intestinal tract are destroyed. It is important after the use of these medicines to repopulate your intestines with friendly bacteria so that unfriendly bacteria and yeasts (naturally present in the large intestine in small numbers) do not establish themselves and take over. Again, a good probiotic is essential here.
So, to review the rules of food combining:
Eat acids and carbohydrates at separate meals. Acids are fruits such as oranges, grapefruit, lemons, berries, pineapple, tomatoes, apples, peaches, grapes, plums, pears, cherries, melons and apricots, as well as wine and vinegar. Carbohydrates include all grains, beans, nuts, seeds, potatoes, yams and winter squash.
Eat protein foods and carbohydrates at separate meals. Proteins include meat, chicken, fish, eggs, milk and all mild products.
It is best to eat each day one fruit meal (taken on an empty stomach), one carbohydrate meal, and one protein meal. Both proteins and carbohydrates may be taken freely with the neutral vegetables (all those which are low in starch such as lettuce, celery, cabbage, carrots, cauliflower, broccoli, brussel sprouts, spinach, all greens, turnips, rutabaga, eggplant, green beans, cucumbers, onions, summer squash, asparagas and bell peppers).
Fruits is best eaten alone for it requires little digestion and is ready to pass through the digestive system to be absorbed quickly and easily --- within half and hour. However, because of their high oil content (and therefore long digestion time) cheeses, nuts, seeds and avocados may be eaten with fruit.
While these rules may seem difficult to follow at first for they do go against many traditional American meals, you will find that by changing a few old habits they can be easily adhered to most of the time. Many health care experts recommend the concept of eating only MONO MEALS. This is the practice of eating only one food or type of food at a time (for example: a bowl of fruit or vegetables, or potatoes with yams, or chicken and eggs). There are several benefits to eating mono meals. First and foremost a mono meal is the easiest food to thoroughly and completely digest. Eating this way makes it much easier to ascertain how your body is reacting to certain foods. If you eat a mono meal for breakfast and don't feel well a couple of hours later it is obvious which food is the culprit. We tend not to overeat on mono meals as our taste buds are not overstimulated. Try eating as many mono meals as possible in your day. When you are at a restaurant and this is not possible shake it off and enjoy!!! It is not what you do on occasion that determines your health but what you do every day.