In this modern era of fast cars, fast food, and fast times- our abused stomachs have staged a revolt, or have maybe just thrown in the towel.  Under the unsustainable demands we’ve placed on them- too much work {in the form of stress} and too little pay {in the form of nutrient-poor or allergenic foods}, they are often not able to carry out normal digestive functions.

First, let’s look at this problem through the lens of the brain.  As I discussed in my post on digestion, our bodies are programmed much the same as they were in the early days of our existence as a species.  A stressful situation is a stressful situation, is a stressful situation.  To our brains, it doesn’t matter whether your village is being threatened by a forest fire, you’ve got a thousand things to do before that party you’re hosting on Saturday, or you had a reaction to the food that you just ate.

Reactions to these stressful situations are mediated by our autonomic nervous system.  The hypothalamic-pituitary-adrenal axis, or HPA axis {sometimes also referred to as the limbic-hypothalamic-pituitary-adrenal axis} is a complicated neuroendocrine relationship comprised of the named organs and glands, that controls the switching between divisions of our autonomic {or peripheral} nervous system.  These divisions are known as the sympathetic and parasympathetic systems.  They each have their own set of nerves that originate from the spine and control the function of each system.  Both sympathetic and parasympathetic functions are required to maintain homeostasis, and function constantly and simultaneously at varying levels.

Parasympathetic dominance is an anabolic state, which is to say that that your body can focus on repairing itself and cleaning house.  Its nerves originate from the cranial and sacral ends of the spine, or head and tail ends.  This is the state that we are designed to be in, unless life has dictated otherwise.  It’s got lots of cute little catch-phrases to describe it, “Rest and Repose”, “Relax and Renew”, “Feed and Breed”, “Chew it and Do it”.  Okay, fine.  I made up that last one.  When we are in this state, we will sleep well, digest and absorb nutrients from our food appropriately, rapidly recover from wounds or illness, cleanse our bodies of toxins.  Key body functions associated with the parasympathetic system are salivation, lacrimation {production of tears}, urination, digestion, and defecation.

Sympathetic dominance, on the other hand, is a catabolic state, meaning that the body is actively breaking itself down.  While this may sound frightening, it is necessary and happens to us all on a daily basis.  We are constantly breaking down bone to set minerals free into the blood stream for stabilization of blood pH or breaking down muscle or glycogen stores in the liver for energy production.  The nerves directing this division of the nervous system originate from the thoracic and lumbar {or middle} sections of the spine.

The sympathetic nervous system is responsible for the “Fight or Flight” response.  What does breaking down have to do with fighting or flighting?  The answer is simple and comes from a time remote in our past.  Our bodies are wired to respond to anything perceived as a threat either by fleeing or by combating.  Both of these functions require large amounts of energy.  In the vast and innate wisdom of our physiology, we are prepared for just such an emergency- equipped with specific nerves to take over, to let every non-essential function of our body know that its time is not now.

Digestion can wait.  Healing of wounds, sayonara.  Production of urine and feces- take a rain check.  Procreation, go get a room somewhere else.  Eyes and mouths get dry.  Heart rate increases.  Blood vessels constrict to increase blood pressure for speedy transport of nutrients for energy, and protection in case of a possible bleeding injury.  All available energy stores are pulled from the liver and muscle.  In no uncertain terms, the body prioritizes the function of the brain, heart, lungs, and extremities.  See?  When evolution sees a thing that works- it sticks with it.


Digestion is energy and nutrient intensive, not compatible with most other body processes.  Walk through any cafe in Paris and see friends engaged in conversation, no attention to any moment beyond the one they’re in.  Peek into a countryside home in Spain where all family members have come home from work and school to enjoy a relaxed midday meal together.  And nothing reverberates with peace and utter bliss like a baby napping after filling its tiny belly.


This is the good stuff in life.

But it’s more than that.  It is tradition in harmony with physiology.

Our bodies are designed to eat in peacefulness and digest in peacefulness.  We need this state of parasympathetic dominance to slow our heart rates, increase organ and gland activity {including peristalsis and hydrochloric acid production}, to relax gastrointestinal sphincters.  Sympathetic dominance can be a real hindrance to good health.  Until I get around to writing my own post on sympathetic dominance, check this great article out.


Ugh.  So alarmist.  So categorical.  So permanent.  How many times have I heard my mother and grandmother scold me with this statement over the years?  And come on, did those shock waves of teenage fear as I stood clutching my bag of Cool Ranch Doritos have any value?

Well, yes and no.  Yes, in the sense that a fat cell {or adipocyte} is never truly destroyed outside of a good dose of liposuction, preferring to simply adjust its size.  No, in the sense that there are so many factors that go into this equation- What did you eat?  What is your level of activity?  What are your underlying health issues?

This last question is what I’d like to focus on while dancing the digestion/brain dance.  Sympathetic functions of the body are regulated by many hormones, the immediate go-to guy being adrenaline {also known as epinephrine}.  Adrenaline will get you up the tree and away from the man-eating tiger, but is not meant for long term mediation of stress.  So when its job is done, cortisol takes the wheel.  Cortisol is a glucocorticoid hormone {synthesized from cholesterol} and is produced in the adrenal cortex, or outer region of the adrenal glands.

The impacts of this hormone ripple throughout our body and reflect the sympathetic if-it-ain’t-gonna-save-me-don’t-do-it philosophy.  It does, however, shift its gaze more toward surviving a longer term stress.  In fact some scientists have hypothesized that, historically, a predominant function of cortisol was to prepare us to survive winter or other periods of time when food resources were sparse.

Here is a sample of what cortisol beefs up to save your life:

  • Energy production, by stimulating gluconeogenesis {the production of glucose, in the liver, from amino acids, glycerol, lactate, and/or propionate, stored elsewhere in the body}
  • Heart rate and blood pressure, to get the maximal amount of energy and oxygen to your brain and muscles
  • Hepatic detoxification, to speed the body’s deconjugation and conjugation of hormones and metabolites, whose production theoretically increases during emergency situations
  • Appetite, to supply more calories for conversion to energy
  • Adipocyte {fat cell} maturation, for storage of that extra glucose your increased appetite rounded up

Here are a few things it puts the kibosh on to save your life:

  • The immune system, by down-regulating antibody production and inflammatory pathways and up-regulating anti-inflammatory pathways
  • Bone formation, as well as decreasing calcium absorption in the intestines
  • Insulin sensitivity, meaning that it provokes insulin resistance in cells, causing the cells to believe that you are starving

This last point is the one most responsible for the weight gain associated with stress.  As cells become insulin resistant {refusing to allow glucose in for conversion to usable energy}, they begin to see themselves as the starving subjects of a Sally Struthers Christian Children’s Fund infomercial.  The truth is that plenty of glucose is circulating through the blood stream, but lacks the insulin receptor keys to enter those tiny cell palaces.  The body, in an attempt to remedy this perceived “starvation”,  sends up smoke signals telling us to EAT MORE FOOD, exacerbating our weight gain.

In addition to this, cortisol actually promotes the liberation of glucose and other nutrients stored in the body that can be converted to energy {from peripheral adipocytes, muscles, etc.} and relocates them to adipocytes in the midsection.  Why the midsection?  Why not some place a little more sexy, or at least a little less noticeable?  This isn’t completely understood, but is thought to be at least partially a result of the fact that certain cells require insulin for entry of glucose and some don’t.  Cells in the muscles of our arms and legs do.  Cells in our abdomens, not so much.

Nothing beats stress like stress and a muffin top.

Tune in next post for some suggestions on how to help {and not help} your inner Buddha.

Same Bat time.  Same Bat place.





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