Obesely Speaking

The brain and obesity

Symbolic Eating

When compulsive overeating becomes a language.

There are two types of human reality, intrinsic and consensual.  Intrinsic reality is created by nature and consenual reality is created by humans.  Consensual reality is real because we agree, via mass subscription that it is real.  Symbol usage is an example of consensual reality. 

Superior symbol usage is why humans dominate the earth. Language is an example of this. When humans interact symbolically, the symbols are never as important as what they represent. It is not the squiggles on this page that matter, but the thoughts they convey. Communication is crucial to a social species, and is enhanced by symbolic interaction.  Subtract language from the equation and imagine human history. Humans are social creatures and prolific symbol smiths. Therefore, intricate symbolic involvement in our feeding habits naturally follows. 

Understanding any human behavior, always leads back to the brain.  First, and foremost, you must understand that the brain is like a cashier at Walmart on Black Friday. It is beyond busy processing trillions of commands, so consolidating and simplifying information is essential. For example, the “fight or flight” instinct in humans is just the brain consolidating and simplifying, generations of trial-and-error survival lessons

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In discussing symbolism and eating, or symbolic eating, I must reiterate: when humans use symbols it is not the symbols that are important, but what they represent.  It is reasonable to suspect that when we symbolically eat, our brain does not process it like it processes eating to satisfy hunger or hedonic satiation. The ever busy consolidating and simplifying brain, processes symbolic eating like it handles any other symbol. “It’s a symbol, this is how we deal with symbols—Bing—bang—bong—next!” Just like a Walmart cashier on Black Friday.  

Neuroscientists knew the anterior and posterior perisylvian region (perisylvian) was the core of the brain’s language center before voters elected my favorite Republican, Abraham Lincoln. However, recent studies have shown that this region is not solely used for language processing. It activates in various ways for all symbols and their usage. Thus, it plays a more extensive role in communication. The perisylvian links meaning with symbols whether the symbols are words, images, sounds, gestures, or objects. Conceivably, symbolic eating is not processed as a hedonic experience that satisfies a goal-directed behavior, but as gestures (eating event behavior) and objects (food and related utensils and fixtures).  This raises the question: when food or an eating event is used to symbolically communicate, is it processed in the anterior and posterior perisylvian language area as language? 

Curiously, I considered it: A language is comprised of symbols; symbolic eating is communication; the brain likes to consolidate and simplify. Maybe symbolic eating is processed as language. Then the neuroscientist in me said did you have a stroke. Just because we communicate symbolically with food doesn’t mean we’re excluded from the goal-directed behavior of satisfying hunger or hedonic eating pleasure. It certainly doesn’t exclude us from eating that is driven by stimulus-response behavior encoded in the dorsal striatum. They are not mutually exclusive, and though not synonymous, they are often joint ventures. It’s like Santa Claus asking if you’ve been naughty or nice. A better question is why can’t you be both. (Don’t judge me)

Humans commonly symbolically interact through eating. For example, sitting at the head of the table symbolizes head of the house.  Being selected to carve the Thanksgiving turkey is a symbol of honor.  Likewise, holidays have traditional, symbolically associated, foods. So, during holidays and sit down dinners, we often symbolically eat or interact. We eat symbolically eat comfort foods for nostalgia because they have personal meaning. Sometimes comfort foods are comforting because of the neurochemical benefits of the carbohydrate or fat content. That’s a different discussion. Today, we’re talking about the foods that comfort us because of their symbolic association with people or events in our lives.After thinking about this, I made a comfort foods list. The list looked liked the first draft of “War and Peace”. I could hear my arteries clogging as I typed it, but it was quite revealing. I will discuss it later. 

 Humans have many uses for symbolic eating other than holidays and comfort foods. Certain foods symbolize wealth and social class, e.g., Almas Caviar ($25,000/pound), or the NYC Westin Hotel’s $1,000.00 bagel. Lovers use food to signal intimacy by coquettishly feeding each other in public. Humans ascribe a maternal association to food. Some badly abused children use chewing and compulsive eating to symbolically destroy the mother, while other abuse survivors use chewing and compulsive eating as a symbolic replacement for maternal love.

The reason symbolic eating is problematic for compulsive overeaters is simple, yet complex. Symbol usage, like most brain function, relies on learning, memory, and emotion. The brain’s learning system is adaptive, responds to relevant life events, and remains stable when events are not relevant. Emotional importance determines how learning is prioritized and encoded in our hierarchal memory systems. Although human memory is stored variously, we are only concerned with the explicit hippocampal and implicit amygdal memory systems.

The hippocampus wraps around the amygdala like a jellyroll in the lower front of the temporal lobe. The amygdala is indispensable for feeling and recognizing certain emotions.  It mediates our reaction to important survival related events. Hence, incoming stimuli of possible food, sex or threat, or are cardinal amygdala concerns.   

The brain sends potential threat stimulus to the thalamus, which acts as a clearinghouse. The thalamus dispatches the input over two parallel pathways: the short-cut, which goes straight from the thalamus to the amygdala, and the long way home, which goes from the thalamus to the amygdala via the cortex. The short cut allows for a fast, but rudimentary, impression of the situation, because it is a sub-cortical pathway and the discriminating processes occur on the cortex. 

The information sent via the short cut activates the amygdala, generating an immediate emotional response. In the meantime, the sensory information sent the long way is processed in the cortex. The cortex sends a signal to the amygdala saying whether or not there’s a real threat. This requires various levels of cortical processing. 

The primary sensory cortex processes the input first. Then the unimodal associative cortex provides a secondary depiction of the stimulus for the amygdala, followed by the polymodal associative cortex’s conceptualization of the information. This detailed picture of the stimulus is then compared with explicit memory in the hippocampus. 

Explicit memory is required to learn how dangerous something is. The hippocampus is particularly proficient at encoding contextual facts associated with aversive experiences. So, not only can specific sensory information become a source of conditioned fear, the surrounding factors associated with the experience can be collateralized as well. Research says emotional eating is commensurate with aversive life experiences. Research also reports that aversive experiences are higher in compulsive and binge eaters than in normal eaters.  Emotional eating is always symbolic eating and among the chief architects of compulsive and binge eating. The probable source of conditioned fear is the associative, collateral context of aversive objects and events. It’s also likely that compulsive overeaters have more conditioned fears than normal eaters because they have more aversive experiences.    

Many of our conditioned reflexes and conditional emotional responses are stored in implicit memory. The associative learning in humans, which forms the basis of implicit memory, is an ancient, phylogenetic, process. It’s in that old part of the brain that sometimes just makes you want to crawl on your belly like a reptile. (Don’t judge me). Subcortical processes, like associative learning, don’t have the advantages of cortical input. So, we are not aware of forming implicit memories, nor is thought needed to retrieve them. This is very bad news for compulsive overeaters.

When we experience trauma, implicit and explicit memory systems record different aspects of the event. Later, the hippocampus allows for remembering where, when and with whom it happened, and what scents and designer labels were worn for those brains that are slaves to fashion and fragrance.  We do not realize that implicit and explicit memory are distinctive and specialized because they are activated by the same memory indexes.  

This parallel operation of explicit and implicit memory systems is why people don’t remember trauma between birth and 2 ½ years old. During this time, the hippocampus is still immature, but the amygdala is already capable of encoding unconscious memories. This is why early traumas can breech adult mental processes and functional behaviors by mechanisms that are not consciously accessible.

 The amygdala, like the hippocampus, pairs most of its in-bound and out-bound pathways. The ventral amygdalofugal pathway plays an important role in associative learning of conditioned fear. Fugal means to drive away, as in fugitive. The ventral amygdalofugal pathway is important because motivation and drive influence responses via the limbic system. Responses are also learned here. The attractive or repulsive nature of a stimulus is established by this pathway’s connectivity to the nucleus accumbens, which is the key player in the brain’s pleasure-reward circuitry and habit formation as discussed in my previous post, Compulsive Overeating and Habit Formation. Excellent studies link adverse childhood experience with hippocampal and other structural remodeling as well as alterations in neuroplasticity. 

There in lies the fons et origo of why symbolic eating is problematic for compulsive overeaters. If your hippocampus has been remodeled due to adverse childhood experiences, your learning and memory is permanently affected. All of your sensory experiences, after being depicted by the cortex are reconciled with the hippocampus by the amygdala to determine the decibel of your emotional response. If your hippocampus has been remodeled because of adverse experiences that comparison, and in turn the amygdala response, will reflect those alterations. 

So, what you feel when you encounter aversive stimuli may be totally appropriate based on the context of your experience, and subsequently how your brain is wired and works.   However, depending on your life experiences prior to reachng 2.5 years old there could be a disparity in implicit and explicit memory reconcilliation.  This is because your amygdala starts encoding conditioned fear responses into implicit memory before the hippocampus is fully formed.  So two scenarios could occur: 1) hippocampal remodeling could cause life events to symbolically magnify the significance of an event, reaulting in a higher dicibel of response than necessary by amygdala, or 2) the amygdala could be preset to respond at a higher decibel depending on the conditioned fear responses that encoded in implicit memory before the hippocampus was developed.  

All humans possess the mechanism to eat over feelings.   It's how many times you employ that mechanism that becomes problematic with compulsive overeaters.   That just depends on the variables in your environment in the context of your brain's presets.  It is like we all have the capacity for violence.  That is not the problem.  The problem is what external and internal cues cause us to access that capacity.   For the gang kid, the symbol of disrespect can result in violent assault or death.  For the compulsive overeater that symbol can cause compulsive overeating, which is just a differently directed assault and a slower death.   

There is the complex, now for the simple. The world grows obese for the same reasons I did: When people are continually battered, and abused, they find comfort and shelter where they can; eating satisfies the ancient brain.  There is subcortical shelter and comfort in that.  

When examining my comfort food list, I realized although I have a congress of comfort foods, all of them made the list for the same reason: I love or need what they represent. This, more so than the perisylvian language cortex is where symbolic eating really becomes a language—a potentially lethal mode of expression that speaks to us, or for us, when we cannot speak for, or to ourselves. But like all language and symbolic interaction, symbolic eating is a consensual reality.  It is only real because we reify it by mass social subscription, hence our compulsively symbolic-eating world.

Compulsive symbolic eating is global because the world is starving for the staples of humanness. Desperate, we turn to symbolism because humans are symbol smiths and that’s what we do. Our symbolic eating is a cry that says: “We hunger to love and be loved; we hunger for the shelter of family and community; we are starved to belong, hungry for a reason to believe, and famished for something to believe in. We crave a kinder, more salubrious world that will not do unspeakable things to us, and snicker while we tremble, laugh as we bleed, and say, you’re too this, you’re too that, you can’t go here, you can’t be that, you’re too old, you’re too bold, you’re too white, you’re too black, you’re too thin, you’re too fat. We are a malnourished social species, starving for one world, one people, on a planet where you can drink the water and breathe the air.

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Billi Gordon, Ph.D., is Chair of the Advisory Committee for Collective Concerns in Medicine, David Geffen School of Medicine at UCLA.

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