The Ultimate Guide to Glucose And How It Works
By Tyler Woodward
- The Benefits Of Consuming Glucose
- How To Maintain Your Blood Sugar Levels
- Why Glucose Metabolism Is Necessary For Optimal Health
Table of Contents:
- What Is Glucose?
- Blood Sugar
- Insulin & Glucose
- What Is Diabetes?
- Glucose Vs Fatty Acid Metabolism
- What Are Healthiest Types Of Sugar?
What Is Glucose:
Glucose, also known as dextrose, is one of the three naturally occurring simple sugars or monosaccharides that is present in many of our foods and beverages. Glucose naturally exists in a 6-carbon ring structure and is the only simple sugar that can be directly absorbed into the bloodstream and used as fuel by our cells. Glucose present in our bloodstream is referred to as blood sugar or blood glucose. All other carbohydrates that we consume must be broken down into glucose, absorbed through the liver (fructose), or excreted as waste (cellulose or fiber).
Glucose is one of the six main types of simple sugars, but it is not be confused with sucrose which is typically what people are referring to when they say sugar. Sucrose is a disaccharide (two sugars) that is made up of one glucose molecule and one fructose molecule.
If you're interested in learning more about the various types of carbohydrates and sugars make sure to check out our article, "Carbohydrates: The Macronutrient Guide".
Keeping our blood sugar levels within the normal range is a key part of maintaining homeostasis. The normal range of blood sugar glucose will vary slightly from person to person and will change throughout the day in relation to your last meal. It is estimated that average blood sugar levels for a healthy adult range from 70-110mg/dL1 (milligram per deciliter).
The higher the glucose content of a meal, the larger the increase or spike in blood sugar will be. Although complex carbohydrates like starches are made up of hundreds to thousands of glucose molecules, they take longer to digest because they must be broken down into individual glucose molecules. This extends the amount of time it takes for all the glucose in complex carbs to enter the bloodstream. It’s also worth noting that foods with a higher ratio of fructose: glucose will help to limit large jumps in blood sugar because fructose can only be metabolized by the liver.
The Glycemic Index (GI Index) was invented by Dr. David Jenkins in the early 1980s as a method of ranking carbohydrates by their effect on increasing blood sugar levels. It should be noted though that the GI does not actually take into account the quantity of the carbohydrates you eat.
Insulin & Glucagon:
It’s extremely important that your body’s blood sugar levels remain within their normal range or you can experience hyperglycemia from high blood sugar or hypoglycemia from low blood sugar. Hypoglycemia can cause fainting, dizziness, anxiety among a string of hormonal and other health disorders. While hyperglycemia can cause fatigue, headaches and over time Type II diabetes in extreme cases. To combat this through evolution we have evolved a feedback loop that is constantly at work to regulate our blood sugar levels.
After a meal as our body begins to digest and breakdown the food and our blood sugar levels begin to rise. The beta cells in our pancreas then release insulin in our bloodstream, signaling to our cells to absorb glucose from our bloodstream. This will be used as energy or stored for later as glycogen or fat if there is an excess. As our cells absorb the glucose from our blood stream, our blood sugar levels begin to decrease and our pancreas slows down and eventually stops the release of insulin.
After going a few hours without eating our blood sugar levels begin to decrease. The alpha cells of the pancreas begin to release glucagon into the bloodstream, signaling to our cells to begin to break down their glycogen back into glucose to be used as energy. At this point, the liver also begins to break down its glycogen stores and release glucose into the bloodstream to keep our blood sugar from falling too low. Glycogen is primarily stored in our liver and muscle cells and an adult liver is estimated to be able to store between 100- 120 grams of glycogen.
There are two main types of diabetes all of which center around the hormone insulin.
Diabetes Insipidus (Type I Diabetes) -
- Formerly known as juvenile-onset diabetes, this is an extremely rare autoimmune disorder in which it is believed that the immune system attacks the Beta cells (cells that produce insulin) of the pancreas, rendering greater than 90% of them destroyed. This leaves the body unable to produce insulin. Type I diabetes makes up about 5-10% of all diabetes.
Diabetes Mellitus (Type II Diabetes) -
- Formerly known as adult-onset diabetes, Type II diabetes results when our cells develop insulin resistance and more insulin is required to keep our blood sugar levels in check. The pancreas initially increases its insulin production, but over time as the cells become increasingly insulin resistant they cannot keep up. Diabetes mellitus has become more and more common over time and is now not uncommon to see in children and adolescents. It is estimated that about 80-90% of people with type II diabetes are overweight or obese and is likely preventable by maintaining an healthy lifestyle and diet.
Both forms of diabetes require exogenous (produced from outside the body) insulin to be injected in order to regulate your blood glucose levels.
Read More: 10 Ways To Lower Blood Sugar Effectively
Glucose Vs. Fatty Acid Metabolism:
As humans there are two primary methods that our cells can produce energy from food:
- Glucose (Oxidative) Metabolism - also known as cellular respiration is the process of converting glucose and oxygen into energy in the form of ATP (adenosine triphosphate), carbon dioxide (CO2), and water. Glucose metabolism will always result in the formation of 36 ATP (as long as oxygen is present) and 6 molecules of carbon dioxide.
- Fatty Acid Metabolism or Beta Oxidation - is the process of converting fatty acids into carbon dioxide and ATP. This is the body’s built-in backup system. The amount of energy produced through fatty acid metabolism will vary depending on the size of the fatty acid being broken down, as they can vary greatly in the number of carbon molecules each contains. Fatty acid metabolism is a much slower process and releases a lot less CO2 and more lactic acid as byproduct.
To understand why cellular respiration (glucose metabolism) is superior to fatty acid metabolism in order to achieve optimal health we have to dig a bit into human physiology and biochemistry.
When we take a breath, our lungs fill up with oxygen from the atmosphere. This oxygen is absorbed into our bloodstream through our lungs and taken into the heart where it is pumped into our arteries and distributed throughout the body. Cells throughout our body take in this oxygen and release CO2, which gets pumped back into the heart through our veins and eventually released from our lungs. The key component in this equation is hemoglobin. Hemoglobin is the main protein present in our red blood cells and is responsible for transporting both oxygen and carbon dioxide. It does this through two processes known as the Bohr and Haldane effect.
Hemoglobin naturally exists in two shapes or conformations in our blood depending on whether it is bound to oxygen or carbon dioxide. In the lungs where there is a large amount of oxygen present, hemoglobin will have a high affinity (attraction or willingness to bond) for oxygen and will change to its oxygenated form, releasing any bound CO2 in the process. This is known as the bohr effect. Oxygen also exhibits a cooperative property, meaning that after the first oxygen molecule binds to hemoglobin the second, third and fourth molecules bind much more readily.
Throughout the body in our tissues, there is very little oxygen present and there is a lot more CO2 present due to cellular respiration. The increases CO2 levels in our bodily tissues results in a lower pH level (more acidic) due to CO2 being slightly. This causes the hemoglobin molecules to shift to its “deoxygenated” form increasing its affinity for CO2 and allowing it to release O2 into our body tissues as it picks up CO2 to bring back to the lungs. This results in a positive feedback loop in which the more CO2 released by our cells and tissues through metabolism, the more oxygen they can absorb and use for metabolism. Resulting in more energy production and a higher metabolic rate.
For this reason, glucose metabolism is a significantly more efficient method of creating energy than fatty acid metabolism because it encourages the use of more energy. In the words of the Research Cowboy, if we want to achieve optimal health we want to have a wasteful metabolism. We want our cells to have so much energy they basically do not know what to do with themselves and will begin to radiate heat and energy and influence the cells around them to do the same. This allows our cells to operate at a highly efficient level and provides them with a surplus of energy for growth and repair.
This is in contrast to the fatty acid metabolism, the fatty acid metabolism is a conservative metabolism. As I stated before, fatty acid metabolism is our body’s built-in back system designed to be used in times of stress and famine in order to preserve our body’s glucose supply. In fact, it is the release of the stress hormones cortisol and adrenaline that triggers the release of fatty acids into the bloodstream, allowing for them to be absorbed into our cells. The more fatty acids present in the bloodstream, the harder it is for cells to absorb glucose instead of fatty acids when insulin is released. Over time, if fatty acid levels in the bloodstream remain high this leads to insulin resistance, as the cells require more insulin in order to be able to absorb the glucose present in the bloodstream. This is a process known as the Randle cycle and results in a negative feedback loop of decreased energy production.
It should be noted that the fatty acid metabolism is not “bad”. Without it we likely would not have survived as a species and it is still necessary today in order to lose weight. The key is to minimize the amount of fatty acid metabolism that occurs by eating sufficient carbohydrates. For these reasons, we do not recommend the keto diet. The keto diet significantly increases the amount of stress placed on your body and if anything puts your body in a worse state to lose weight/fat in the long run.
Why have I heard that the Keto Diet results in faster weight loss?
Initially, the keto diet does result in weight loss, but this is a loss in water weight, not from fat. With very little carbohydrate intake your body is rapidly depleted of its glycogen stores which regulate water storage in our cells. So as the glycogen stores are used up, our water stores leave right along with it.
Why have I heard that people feel so great on the keto diet?
This is due to a phenomenon known as catecholamine honeymoon. Due to increased amounts of adrenaline and cortisol in our bloodstream from relying on fatty acid metabolism people experience a surge in energy and focus for a period of time. Again, this makes a lot of sense from an evolutionary perspective. If we felt terrible and sluggish during this “starvation” period our body is experiencing, we would have a lot less energy to go out and scavenge for food. It should be noted that this catecholamine honeymoon is short-lived and typically only lasts for a few days to weeks. The elevated stress levels from the keto diet inhibits our thyroid from functioning properly and cannot produce enough thyroid hormone. Over time, this results in decreased production of pro-metabolic hormones like testosterone, progesterone which can lead to severe health issues over time.
What Are The Healthiest Types Of Sugar?:
If you're looking to up your sugar game, make sure to stick with naturally occurring sugars and to purchase a high-quality organic form that is farmed without the use of pesticides. Here are a few of our favorite types of sugar:
Pure raw cane sugar
Fruits & Roots
My goal in writing this article, as always, is to provide you with logically-based principles that you can use to form your own conclusions regarding any information you may come across within this subject. I really hope you found this article interesting and if you have anything to add to this article, or any comments or criticism, feel free to reach out to me on our facebook groups (The Thermo Diet Community Group, The UMZU Community Group) or on Instagram @tylerwoodward__. Also, please feel free to share this article with anyone that might be interested.
Thanks for reading!
Until next time… be good
B.S. Physiology and Neurobiology