Human Anatomy at Colby

Choose your Poison

January 25, 2013 · No Comments

Everyone knows about alcohol poisoning… but what about poisoning by sugar?  Yesterday in class we learned a lot about the hormones in the gastrointestinal tract and how your body digests sugar.  I thought I had a basic working knowledge of how my own body digests food and absorbs nutrition, but what I learned yesterday totally blew that I thought I knew out of the water.

by Sonia Vargas, Colby College ’15


According to Forbes, over 65% of the United States is overweight and 35% of that percentage is obese.  The United States is currently home to over 312.8 million people.  That is over 203 million people that are overweight in this country, and 109.5 million of those people are obese.  Those numbers are staggering.  In many places around the world, the numbers are just as bad, if not worse.  In China, there were nearly 100 million obese people in 2011.  In Mexico, 70% of Mexican adults are overweight and 29% are obese.  Even in countries that are more associated with malnutrition, obesity rates are rising.  The list goes on and on of startling statistics from all over the world, but all the numbers and figures point to an overwhelming problem: a pandemic of obesity worldwide.  An estimated 42% of the entire world’s population will be obese by 2030 according to a 2012 study funded by the United States Center for Disease Control and Prevention.

It’s no secret that being overweight is bad for your health and is directly related to a higher risk of serious health complications such as heart disease, type 2 diabetes, cancer, stroke, liver disease, high blood pressure, and gallbladder disease.  Oftentimes, being overweight is associated with a social stigma of laziness or inactivity, and this stigma can cause low self esteem,  depression, and feelings of worthlessness and or helplessness in people struggling with managing their weight.  However, this stigma has a backwards way of blaming the victim.  Pediatric Endocrinologist Dr. Robert Lustig explains in Sugar: The Bitter Truth, “No one chooses to be obese, and certainly no child chooses to be obese.”  An epidemic of obese 6 month olds around the world should convince you that there is a problem that is larger than a bunch of people with poor diets and lack of motivation to exercise. According to NBC in 2009, sugar intake in the United States was about 141 pounds of sugar per person, per year.  Dr. Robert Lustig says in reply, “Don’t you think that this would have a detrimental effect on you? But it hasn’t stopped you, has it? That’s the point, it hasn’t stopped you. And that’s why we need to talk about it.”

However, there have been recent developments in the scientific community that show that obesity is a symptom of a much larger problem.  In the extremely informative documentary series, The Skinny on Obesity, Dr. Robert Lustig explains the cycle of hormones that regulate hunger in your body and how for many people it becomes a vicious cycle.


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Hunger in your body is controlled by two main hormones that relay messages from your stomach and fat to your brain: ghrelin and leptin.  Ghrelin is secreted by the stomach wall, and is the hormone that signals to your brain that you are hungry.  Leptin is produced by fat tissue and suppresses appetite.  When you have more fat, your body produces more leptin and you are supposed to feel less hungry.  However, obese people have abnormally high levels of body fat and therefore abnormally high levels of leptin.  So why do they continue to gain weight?  If leptin was doing it’s job, they would not be obese in the first place.  Dr. Robert Lustig explains that this is the result of leptin resistance.  He also explains that his research shows specific, significant findings that Insulin may be a main cause of leptin resistance.  The cycle is this:  you eat more sugar and you don’t burn it off, so your body is forced to store it as fat.  That extra sugar causes your body to produce more insulin.  The insulin converts the extra sugar in your blood to more fat in your body.  More fat equals more leptin, and too much leptin overwhelms your brain and allows it to build a resistance.  Your body still produces ghrelin to make you hungry, but your brain is not getting enough of that “I’m full” signal from leptin, so you still feel hungry even after you have eaten enough calories.  You store the excess of what you’ve consumed as more fat. To sum it up: more sugar = more insulin = more fat = more leptin = more resistance to leptin = more calories consumed to satisfy hunger = more fat = obesity.  Dr. Robert Lustig also believes that insulin blocks leptin at the brain, which also helps increase your feeling of hunger.  You can’t fight your own body when it comes to the basic, biochemistry that drives you.  It’s weird to think of sugar as being what Dr. Lustig describes as, “toxic and abused,” but so many processed foods sold in the supermarkets are laced with the unhealthy amounts of sugar that cause this hormonal imbalance.  Whether it be because of financial issues or simply just the lack of other viable options in the grocery store, many people don’t have a choice but to eat these highly sugared, processed foods.

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 “If you have no choice, how can it be personal responsibility?  We’ve been told what to eat by the nanny state of the food industry, and we’ve gone along with it because it’s sweet.”- Dr. Robert Lustig

For the last 30 years, nutritional advice has been centered around getting rid of fat.  It is not uncommon to seek weight loss advice and to hear, “Lower your fat intake, and increase your exercise.”  While a regular exercise regiment is great, just lowering your fat intake is not enough.  While fat in our diets is going down, if the sugar is going up we still have a major problem.  Many processed foods that are “low in fat” contain extremely high sugar contents to make up for the lack of taste. Anything that is processed and is advertised as “low fat”, “sugar free”, or “fat free” should be treated with suspicion.  Many times these products are filled with chemicals, sugars, and salts to replace the fat that is being stripped away.  Some fatty foods are actually really good for you, such as avocados, eggs, and nuts.  It’s becoming clear that a high sugar content is a much more troubling health risk than relative fat content.  Also, the way your body digests sugar is interesting to consider when trying to improve your health. Table sugar is a form of sucrose, which when broken down in the body becomes one glucose molecule and one fructose molecule. Glucose can be digested by pretty much any organ in your body, and is necessary for many life sustaining metabolic reactions.  Fructose however, can only be digested by the liver.  A high consumption rate of fructose over years can lead to liver damage that resembles liver damage caused by alcohol abuse.

Metabolic Syndrom

 “Many of the health hazards of drinking too much alcohol, such as high blood pressure and fatty liver disease, are the same as those for eating too much sugar. When you think about it, this actually makes a lot of sense. Alcohol, after all, is simply the distillation of sugar… Most experts are worried about sugar because it’s “empty calories” that make people fat. But what leads to chronic disease is actually something called metabolic syndrome, which can be caused by the toxic effects of sugar.”- Professor Laura Schmidt, Medical Sociologist

The scariest part about all of this new research is that children can inherit this hormonal imbalance from their mothers.  Babies can be born with disproportionately high levels of insulin because the mother’s high sugar levels travel across the placenta to the baby in the womb.  When a mother’s blood sugar is high, so is her baby’s inside her. The baby will make extra insulin to keep its own blood sugar normal, and this can cause the baby to put on extra weight and be born with the same hormonal imbalances and health risks that obese and diabetic adults battle with.

From what I’ve learned in this class, I can give a few tips to my friends and family who want to have a healthier diet: try to cut out high-fructose corn syrup from your diet, watch your sugar intake, increase your fiber consumption, eat whole grains, eat fresh fruits and vegetables uncooked or steamed, and consume lean proteins like poultry and fish over beef and pork whenever you can.



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