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Seven Deadly Sins Sunday: Gluttony Part 5

 

In Part 1 of “Gluttony”, we set up the concept of Seven Deadly Synapses the book.

 

 

In Part 2, we looked at how an Oreo cookie is broken down and ends up either becoming a part of us, or being released in the toilet.

In Part 3, we looked at our motivations for eating, and how they might be altered by chemicals made by our bodies, or even chemicals coming from hitch-hiker microbes.

In Part 4, we saw how our genes may be driving the process of gluttony.

This is the last installment in “Gluttony”. Before we leave this sin, we’ll take a visit to Dante’s vision of Hell, and his view of the Gluttons.


Gluttony

Part 5

Gluttony, then, is when the body takes in more energy than it needs. “Need” is defined by a complex mix of hormones, hypothalamic settings and body composition. If the glycogen tank is empty, the first 2000 extra calories are stored as glycogen, ready on a moment’s notice and easily burned. When the glycogen tank is full, at about 2000 reserve calories, then the excess is stored as fat, which is harder to get rid of and not so easily burned. The balance can be tipped toward fat storage by the hormonal makeup of the body, and as we’ll see, the hormonal balance is tipped by fat storage. It’s a complicated example of what scientists (influenced by engineers) call a “positive feedback loop”.

Fat has a lot of chemical bonds. All those bonds in fat contain a lot of chemical energy. When the fat is broken down, that energy is released. Fats in our food give us about 4000 calories per pound; proteins and carbohydrates (sugars), less than half that.

Nutritionists estimate that it takes 3500 excess calories to store one pound of fat. (If a pound of lard contains 4000 calories, the other 500 calories were used to digest, synthesize and package the fat as it moved from our mouths to our bodies.)

Fat (“adipose tissue”, if you want to be polite) is a selfish organ. It uses hormonal signals to command the formation of more fat. More of the body’s energy is then stored as fat, and the cycle spirals ever downward, towards overeating and obesity. The body takes in excess food calories; the extra calories are stored as fat; the fat directs the body to seek out more calories; the body takes in excess food calories. Gluttony ensues.

As Dante and his party descend to the third circle of Hell, not far from the entrance and so inhabited by a sort of minor sinner who is still subjected to unspeakable torture, they encounter the Gluttons.

 

The health effects of gluttony, and the social stigma that goes along with it, makes its victims want to approach the perfection that Dante’s sinners craved. Still, gluttony is a tough nut to crack. The mechanisms that control “normal” feeding behavior are complex. Our understanding of the ways in which fat works as an endocrine (hormone-releasing and hormone-receiving) organ are incomplete. Over and over again, scientists have identified a “magic bullet” such as leptin, only to find that the system is designed with multiple control loops, all knotted together and all designed to be resistant to any intervention. No single factor seems to be enough to banish gluttony.

The stakes are high. Fat’s effect on health are well-known, and it would only make me a scold to recite them. Obesity almost always leads to a follow-along disease, only defined in the last few dozen years, called “Syndrome X” or, more recently, “metabolic syndrome”.

Metabolic syndrome is comprised of: a waistline that is too broad, too much cholesterol in the blood, increased blood pressure, too much sugar in the blood, a tendency of the body to overreact to damage, and a propensity for the blood to clot.

Let’s take these one at a time. A waistline too broad (more than 40 inches for men, 35 inches for women) explain what you’ve heard about the “apple” body type (lots of fat around the waist) versus the “pear” type. Somehow, fat deposited around the waist seems to be different, probably because it tends to release more hormones.

Cholesterol is needed to make the wrappings which keep your cells intact, but too much of it can deposit in the arteries. Cholesterol can’t travel by itself in the blood; it needs to be shepherded to the cells by a carrier protein. Most people have seen the cryptic terms “HDL” and “LDL” on a lab report after their blood is analyzed. The different combinations of lipid and protein form the different subcategories that labs measure. You know from the last time you made gravy or chicken soup that fat floats; floating means low density; so “low-density lipoprotein” (LDL) contains more fat than protein, and that’s the more dangerous kind of cholesterol.

Increased blood pressure occurs because the body is under constant stress; there are more blood vessels, they are narrower than they should be, and they get clogged with fat and clots.

Increased blood sugar is the hallmark of type II diabetes mellitus. Remember the role of the hormone insulin: to move glucose from the blood into the tissues of the body, which need it for energy. As far as we know, something in the hormonal mix caused by the presence of fat causes less insulin to be released, and the insulin that is released doesn’t work the way we expect. It’s a paradox: cells are starving, and cry out for more glucose, but because they have become “insulin resistant”, insulin is unable to effectively move glucose into the cells. Less glucose is absorbed by the cells and it accumulates in the blood.

Inflammation is the general term for the body’s response to injury. If something damages you, or if an invader tries to occupy your body, it’s the inflammatory mechanism that kicks in right away. Inflammation carries risks, however; inflammation in the absence of injury or invasion is doubly dangerous. Metabolic syndrome includes an increased tendency to inflammation. Currently, we don’t have very good ways of measuring this, but a substance called “C reactive protein” is the best yardstick we have.

Increased blood pressure, more lipid deposits on the inner walls of arteries, and increased inflammation, all lead to blood clotting. Let’s say there’s a hole in you. As blood squirts out, there are ripping forces that stimulate specialized cell fragments and proteins in the blood to form clots and plug the hole. In the case of metabolic syndrome, blood pressure, fat deposits clinging to the walls of blood vessels, and roughening of the walls of blood vessels all work to increase the ripping forces on blood. Clots form where they shouldn’t, inside of blood vessels, and then can travel to the lungs, or heart, or brain, causing tremendous damage wherever they lodge — deep venous thromboses, heart attacks, strokes.

I’ve fought gluttony, and I was aware that something needed to be done long before I was able to do anything. It’s not easy. After my successful weight loss, I became a support group leader. Now, I see others fighting the perceived sin of gluttony, and I can see how hard it is to fight alone. It is clear to me what a powerful adversary gluttony is.

Why do some methods work better than others? None works particularly well. The range of choices lies between near-impossible and total failure. In one recent study, people who followed a diet lost an average of two pounds in a year. People who followed a diet and attended a support group lost six pounds in a year. Most of us would find that a minimal benefit. The secret is in the math: if one person loses sixty pounds, but nine others lose nothing, then the average weight loss is six pounds for those ten people. Even the “best” method doesn’t work well. We suffer under the pressure of our fallible human genes, pushing us to gluttony, and we’re driven by hormones and brain circuits that are mostly out of our control. The two weapons we have are willpower and the moral force of groups.

Studies have shown that people gain, or lose, weight in social groups. Just like the body itself has homeostatic balancing mechanisms to regulate a preferred level of substances like glucose in the blood, it seems that people interact with each other to influence their own set points. We get fat in groups, and we lose in groups. Clearly, social support mechanisms (or lack of them) have a tremendous influence on people’s behavior, which we’ll revisit as we look at “Temperance.” Tiny, atomic-level feedback loops in the body’s chemical reactions are controlled by larger feedback loops in cells and hormones, which are controlled by still-larger feedback loops operating at the level of clubs, churches, friendships and families. No wonder we find it so hard to understand the sin of gluttony, much less control it.

Seven Deadly Sins Sunday: Gluttony Part 4

 

In Part 1 of “Gluttony”, we set up the concept of Seven Deadly Synapses the book.

 

 

In Part 2, we looked at how an Oreo cookie is broken down and ends up either becoming a part of us, or being released in the toilet.

In Part 3, we looked at our motivations for eating, and how they might be altered by chemicals made by our bodies, or even chemicals coming from hitch-hiker microbes.

In this Sunday’s installment, we’ll talk about how our genes may be driving the process of gluttony.


Gluttony

Part 4

 

Before the revolution in gene sequencing of the last three decades, which culminated in the Human Genome Project, the main way for genetic researchers to study disease was to catalog and sift through the spontaneous mutations that arose in laboratory mice. For years now, to make genetic research possible, different strains of laboratory mice have been inbred for hundreds of generations. Now, each individual mouse of a strain is essentially an identical genetic copy of its father and mother, a duplicate of its cousins and siblings, and the original from which its unborn descendants are copied.

For example, a kind of shiny black mouse called “C57Bl” is an inbred strain; all mice of this type are genetically identical, except for mistakes and random changes made in the copying process. In one of these mutations, mice begin to get fatter and fatter starting at about four weeks of age, about the time the mice reach sexual maturity. As adults, they’re grossly obese, barely able to move around their cages. Genes are named with a short designator, and since there are two copies of each gene, one from the mother and one from the father, the names of the two gene types are separated with a slash. Because of this obesity, mice that carry two copies of the mutation that makes them fat are called ob/ob mice.

Seven Deadly Sins Sunday: Gluttony Part 3

 

In Part 1 of “Gluttony”, we set up the concept of Seven Deadly Synapses the book.

 

 

In Part 2, we looked at how an Oreo cookie is broken down and ends up either becoming a part of us, or being released in the toilet.

In this Sunday’s installment, we’ll see how chemicals in our brain and even the bacteria that live in our gut drive this process.


Gluttony

Part 3

The brain not only keeps us from suffering social embarrassment from anal leakage, but also has a huge role in determining when, where, and what we eat. If gluttony is a sin, it resides in the brain, not in the automated parts of the gut that lie outside of our control. The brain is a complex organ. There are, scientists estimate, 100 billion nerve cells, about the same number of nerve cells as there are stars in the Milky Way galaxy. Each of these nerve cells makes connections with 10,000 others, on average. To make sense of such a complex organ, it’s convenient to think in terms of levels of organization, and for our purposes, we’ll consider four levels.

Nerve activity in the gut is in waves, which is what moves materials through the gut by peristalsis. Photo: Rolf Hicker http://www.hickerphoto.com/

The intestines form a tube, and all along that tube is a gut nervous system. We saw this earlier when we were talking about peristalsis, the milking action of the bowel. This is a sort of  “housekeeping” function, which occurs to a greater or lesser extent throughout a lifetime. Nerve cells fire in waves, like the ebb and flow of the ocean, and like the ocean the waves can be big or little, or can come in frequently or less frequently, but they’re always there. The gut nervous system, called the enteric nervous system, is influenced by the content of the gut as well. More about this later.

Seven Deadly Sins Sunday: Gluttony Part 2

Each Sunday, I’m excerpting a chapter of The Seven Deadly Synapses, a book on the neuroscience of sin. In this series, we’re examining the sin of Gluttony.

In part 1 of “Gluttony”, we didn’t get to the scientific part. It was mostly just a warm-up. Now it’s time to figure out how the taste system sends a signal to the brain, and how the digestive system handles food.

 


Gluttony

Part 2

For most of mankind’s history, eating has been the key to staying alive and so has been a human’s main job. Most of a person’s waking hours were devoted to getting calories, processing calories into a healthy and digestible form, and storing calories for future needs. The word “famine” appears 107 times in the King James Version of the Christian Bible (including the passage shown here, that describes a famine so severe that a mother boils and eats her son); “hunger” 60 times; “starve”, “starving”, “starvation”, 19 times. Other religious texts show a similar historical fixation with either metaphorical or real hunger: the word is used 74 times in the Qur’an, and only 18 times in the Upanishads. Gluttony is likely to be a sin mostly because it revels in the flaunting of what mankind has struggled so hard, for so many years, to achieve: nutrition.

 

To find food, and eat it, and to balance surfeit with famine, is the responsibility of a few thousand nerve cells in a pinky-end-sized hunk of brain called the hypothalamus. Just like the thermostat in your house keeps the household temperature close to where you want it to be, the hypothalamus is responsible for your body’s balancing acts, the processes and feedback loops that physiologists call “homeostatic mechanisms”. Like Goldilocks, we want our bodies to be “just right”. not too cold, not too hot; not too thin, not too fat; not too much breath, not too little. How the hypothalamus causes us mischief is the root of our story.

Seven Deadly Sins Sunday: Gluttony Part 1

Every Sunday, I’ll print an excerpt from the upcoming book Seven Deadly Sins. Because alliteration is a virtue, not a sin, I’m calling this feature “Seven Deadly Sins Sunday”. Other days of the week will be devoted to other things, but on Sunday we’ll examine the neuroscience of sin.

Everyone wants to read about Lust, but that’s a cheap shot and I want to keep you wanting more, not sated after the first few Sunday posts. So I’m going to start with gluttony. (I mixed a little Lust in just to keep your interest.)

 


Gluttony

Brain science is a big field. With so much scientific real estate to cover, there are not one, but several Holy Grails. You could define the Holy Grail of Neuroscience many different ways. Maybe it’s a rare piece of scientific evidence that makes all the other pieces of the puzzle fall into place. Maybe it’s the chance laboratory finding that helps billions of humans lead healthier lives. Maybe it’s a secret that makes you rich beyond your wildest imagination. I’m sure neuroscientists would disagree on which of these is the most desirable, but if I got to choose, I’d go for all three at once — I’d figure out how to make people eat only healthy foods, and only the food they need. I’d slay gluttony.

Searching for the Holy Grail of Neuroscience will likely involve Killer Rabbits.