The Psychobiology of chewing

Wednesday, May 1, 2013


I recently read this interesting article by Marc David about the significance of chewing and how important it is to our psyche and metabolism. I thought is was worth sharing. Read on:

There’s more to chewing than you might think. It’s arguably the first digestive activity that we bring to a meal, and unlike the chemical processes that occur in our gut, chewing falls under our conscious control. Except of course, when we go a bit unconscious and inhale our food. But chewing is more than a digestive aid. It also has a potent psychological function that helps keep body, mind and emotions in balance. Consider the following:

Have you ever wondered why crunchy foods are so popular, why advertisers promote products on the basis of crunchiness – “super crunchy,” “extra crunchy,” “stays crunchy even in milk”? Have you noticed that whenever you eat your favorite brand of potato chips, pretzels, or crackers, they each have a similar degree of crunchiness? What advertisers understand and capitalize on is that crunching and chewing are primal activities, inborn urges dating back to the first life-forms that ever “crunched” on each other.

So important is the level of crunch that many years ago, potato-chip manufacturers developed a sophisticated apparatus to measure the perceived level of crunch that consumers hear in their heads. The most pleasurable decibel levels were deciphered, and potato chips were subsequently manufactured to these standard orgasmic crunch levels.

From a psychophysiologic perspective, chewing and crunching are natural outlets for inborn aggression.
Throw a piece of meat into a lion’s cage and the lion will likely roar at it, attack it and tear it apart as if it were still alive. The lion must do this because its nature is to be aggressive. But aggression here isn’t meant as some mean, vengeful act. A lion doesn’t attack a jackrabbit because of hate. Quite the contrary, the lion attacks because it loves the jackrabbit.

Like the lion, human beings have a distinct measure of innate aggression, and developmental psychologists often see this energy as first experienced through the infant’s desire to bite. Psychologists call the original oral-aggressive act the “hanging-on bite” to the breast. This is a biting that establishes confluence with the mother. The baby must actively hold on for nourishment and will often keep holding on even when mama has had enough. The tension it experiences when separated from the mother before it’s fully satisfied is typically expressed through crying, screaming and facial contortions.

In the many body-oriented disciplines and psychologies, the jaw is associated with anger and aggression. When these emotions are habitually withheld and left unexpressed, they may become “frozen” on the face as a perpetually clenched jaw or tightened musculature resembling a scowl. Just as a dog clenches its teeth when angered or challenged, so too do human beings channel aggression through the face. From an evolutionary perspective, the process of biting and chewing allows for the release of what psychologists call dental aggressive urges.

Many people habitually fail to chew, swallowing their food almost whole.
They tend to derive pleasure not so much from the taste and texture of the food as from the velocity at which it’s eaten. In such instances we deny an important, natural outlet for tension and fail to experience full satisfaction from a meal. In an effort to free the unreleased tension, we may continue to eat past the point of satiation, turn to other oral based habits like gum chewing, or simply internalize the tension, allowing it to build over time and eventually express itself in chronic emotional or biological symptoms. For many people, TMJ disorder is the result of unexpressed anger that’s looking for an outlet.

On another level, by swallowing food whole, we make a statement about the way we approach the world. We want our hungers in life satisfied but aren’t fully willing to take the necessary steps. This need for immediate gratification is reflected in our refusal to chew. Ironically, a side effect of the short-cut method of not chewing is more hunger. Chewing and tasting are basic to hunger satisfaction. When we limit these simple gustatory requirements, the brain screams for more food. Taste, texture, and satisfaction are literal nutritional requirements.

In one fascinating experiment, scientists deprived a group of test rats the sensation of taste. This group of “tasteless” rats, along with a control group, were placed on a normal rat diet. Both groups ate the same amount of food, and in a short time the taste-deprived rats all died. When the rats were autopsied, researchers could only find one cause of death – clinical rat malnutrition. The scientists could come up with only one explanation – that there are important yet unknown physiological connections between taste and health. Similarly, hospital patients fed intravenously or through feeding tubes that bypass the mouth often report a nagging hunger for taste, and can experience digestive, immune and other health issues. Though the mechanisms that govern these phenomena are little understood, this much is certain: to be fully nourished by food, we must experience it through tasting and chewing

In a comparable manner, to be fully nourished by any experience, we must “taste” and “chew” it thoroughly.
It’s no accident that many of the words we use to describe eating are the same ones used to describe the thinking process. When presented with an idea, the mind will first grasp it and “chew” on it. Our conscious mind breaks it down into its component parts, “tastes” it, then “swallows” it into the subconscious for final “assimilation”. When we accept something without “ruminating” over it or when we swallow something “hook, line and sinker,” or when “biting off more than we can chew,” what we say in our metaphoric language is that just as food works with digestion, so too do perceptions work with the mind. Improper chewing of food or ideas are equally disturbing to our system.

The mouth deserves our nutritional respect. It’s the first step in the digestive process. Here the chemical digestion of starches is initiated with amylase, an enzyme that breaks down the complex carbohydrate molecules in a well-salivated mouth. The mechanical digestion of food is also initiated in the mouth with the process of chewing. The surface area increases as the food is broken down into smaller and smaller pieces. When the food reaches the stomach, the number of molecules exposed to the stomach’s acid and enzymatic environment is maximized.

If we swallow something whole, such as a piece of meat, an abnormal series of events occurs. First the stomach must churn the meat with its own muscular movements to help break it down into smaller pieces, a function it’s not ideally designed to do. Next, we go through the lengthy chemical process of breaking down large pieces of food. Because we started with one large bite, only the surface of the meat remains exposed to the stomach’s digestive juices. To digest the meat further, the stomach may secrete more acid than normal. This irritates the stomach lining, which is the reason many eaters experience acid indigestion. The condition is exacerbated if the food is high in protein. The greater the protein content of the food, the higher the level of stomach acidity required to digest it.

Chewing is a “pacesetter”. Whatever speed and number of times we chew sets in motion a rhythm that our entire body adopts. By chewing rapidly and insufficiently, we initiate an unsettled frame of mind that is reflected in the body as uncomfortable sensations in the digestive system. Chewing at a moderate to slow rate promotes a relaxed, grounded demeanor and for many, a noticeable stronger metabolism

Full chewing need not be a discipline, but can occur spontaneously simply by eating with relaxed awareness, and settling in to an attitude of nourishment with our meals. Rather than concentrate on chewing food, eat your food, savor it, delight in it, and let chewing be a natural part of the eating process.


by Marc David

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