Show Notes:
Sugars are ubiquitous in modern diets. Not only are they extremely prevalent in processed foods as added sugars, often hidden in the ingredient list under a variety of different names, but they are also present in numerous whole foods, particularly fruits and vegetables.
Being that glucose is such an essential molecule, can sugar consumption really be that bad? Well, like most things, moderation may be key. However, sugar consumption in the average American is massive, estimated at 66lbs of added sugar yearly.
Research concludes that sugars consumed in their original form, such as eating fresh fruit and vegetables (think a whole apple, not apple juice), are generally considered to be far superior to added sugars. Those added sugars, meanwhile, have been linked to countless health issues, including:
- Fatty liver disease
- Insulin resistance
- Cardiovascular disease
- Type 2 diabetes
But understanding the physiological mechanisms of glucose in the context of health and performance is far more complicated. No discussion would be complete with understanding blood glucose levels, regulatory hormones, and the pathology of diabetes.
In this episode, I hope to illustrate the physiological mechanisms involved with sugar consumption. Namely, the relationship between sugar, blood glucose levels, and the regulatory hormones insulin and glucagon.
TOPICS:
[2:03] Different dietary sugars
[4:26] Simple vs complex carbs
[6:15] Dangers of excessive sugar consumption
[9:39] Importance of blood glucose management
[13:35] Role of insulin and glucagon
[15:47] Self-testing blood glucose levels
[19:13] How to manage your blood glucose levels
What’s the Deal with Sugar?
Alright, this episode is all about sugar, blood glucose, insulin, and glucagon. As I’m sure you are well aware, there are constant arguments about the role of dietary sugar in health outcomes. Sugar has endlessly been linked to negative health outcomes, yet there is always a camp of people that will defend sugar. But this episode isn’t focused on the argument about sugar as a nutrient and its role in dietary consumption, rather, I hope to illustrate the physiological mechanisms involved with sugar consumption. Namely, the relationship between sugar, blood glucose levels, and the regulatory hormones insulin and glucagon.
So What’s the Bottom Line
Understanding the roles of dietary sugars, blood glucose levels, insulin and glucagon, is critical to optimizing your lifestyle to ensure that you feel and perform your best. This episode will be divided into three primary sections:
- How sugars, carbs, and dietary foods are processed in the body
- The function and importance of blood glucose
- The roles of insulin and glucagon
Dietary Sugars
Sugars are ubiquitous in modern diets. Not only are they extremely prevalent in processed foods as added sugars, often hidden in the ingredient list under a variety of different names, but they are also present in numerous whole foods, particularly fruits and vegetables.
First things first, a little chemistry. Simple sugars are the fundamental unit of carbohydrates, referred to as monosaccharides, with the chemical formula of C6H12O6 [1]. So, for those who remember their organic chemistry, that is 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms.
The most common monosaccharides are glucose and fructose. Glucose is the primary energy source for living organisms, being used for ATP production and stored in muscles in the form of glycogen [2]. Other forms of sugars and carbs, as well as fats and proteins can actually be broken down into glucose. Therefore, glucose can be attained from a variety of sources under varying circumstances. Fructose, on the other hand, is a monosaccharide that is primarily sourced from fruit.
So that’s monosaccharides, with one sugar group. Next are disaccharides, which contain two monosaccharides with a slightly different chemical structure, C12H22O11. Examples of these include sucrose and lactose.
Sucrose is simply the combination of one glucose molecule and one fructose molecule, and these are typically found in table sugars. Lactose, as you may recognize, is found in dairy products. This is why you will see high levels of sugar in milk.
Moving on, there are oligosaccharides and polysaccharides, which generally speaking, contain longer chains of monosaccharides. Common examples include maltodextrins and cellulose. You may even be familiar with HMOs – human milk oligosaccharides – which were discussed in episode 025 as being super important for the development of a healthy microbiome in babies.
As you may have noticed, most of these names end in -ose (o-s-e). If you are reading ingredient labels and see an -ose ending, you can probably assume it is a sugar. But in fact, sugars have numerous names that disguise them on package labels. One article outlines 56 different names of sugars, in which I will link to on the website. Here are a few of the most common [3]:
- Sucrose
- High fructose corn syrup
- Agave nectar
- Dextrose
- Maltol
- Barley malt
- Malt syrup
- Molasses
- Cane sugar
Again, lots more than that, but anything that ends in -ose, or has the words sugar, syrup, or molasses in the name is probably a good indication that it is sugar.
Moving on, you have probably heard about simple carbohydrates and complex carbohydrates. Quite simply, simple carbs are foods that contain monosaccharides or disaccharides. Given their simple structure, they are very easily utilized and can lead to a faster spike in blood glucose, which we will discuss more soon. Examples of these foods include candy, corn syrup, fruit juice, honey, table sugar, and carbonated drinks [1].
Complex carbohydrates contain three or more sugars, your oligosaccharides and polysaccharides. Being more complex, they take longer to digest and have less of an effect on your blood glucose levels. Example foods include fruit such as apples, vegetables such as broccoli, unrefined whole grains, and brown rice.
You may be wondering about starches. An excellent question. Starches are complex carbohydrates with a very high quantity of glucose molecules. For this reason, these can also significantly raise blood glucose levels. Common examples include potatoes, pastas, and wheat.
But as another side note, there is such a thing as resistant starches. Essentially, these are resistant to digestion; it is harder for these complex carbohydrates to be broken down [4]. As a result, they will not be digested as easily and will not spike blood glucose levels as rapidly. This is due to a variety of reasons that we will not explore, but they include the presence of proteins, resistance to enzymatic hydrolysis, and also retrograded amylose [4].
Examples of resistant starches include bread made with whole kernels of grain, durum wheat, uncooked potato starch, green banana starch, and starchy foods that are cooled after cooking. Therefore, pastas and potatoes that are cooked and then cooled in the refrigerator, will actually be more resistant than if eaten immediately after cooking.
Finally, lets quickly talk about fiber. These are non-digestible complex carbohydrates. So, for the context of this episode, we will not worry about them as they will not lead to rapid increases in blood glucose levels, but in fact, can actually help to slow down absorption.
Alright, let’s shift focus to dietary consumption now. Being that glucose is such an essential molecule, can sugar consumption really be that bad? Well, like most things, moderation may be key. However, sugar consumption in the average American is massive, estimated at 66lbs of added sugar yearly [5]. Let me repeat, that is added sugar – about 82g daily. Compared to an estimate from 1790 of just 8lb of total sugar yearly, modern diets are drastically different than all of humanity’s existence before us.
Research concludes that sugars consumed in their original form, such as eating fresh fruit and vegetables (think a whole apple, not apple juice), are generally considered to be far superior to added sugars. Those added sugars, meanwhile, have been linked to countless health issues, including [6]:
- Fatty liver disease
- Insulin resistance
- Cardiovascular disease
- Type 2 diabetes
- *Many of these associations are independent of body weight gain or total energy intake.
In fact, in a publication of the American Diabetes Association on sugar, the following passage is found under the heading Potential Advantages: “There are none. Carbohydrates found in their natural state in combination with other nutrients and fiber are far superior to high-dose refined sugar products in terms of overall nutritive effects and glycemic impact” [5].
To reiterate, foods consumed in their natural form are far superior. The fiber, minerals, and nutrients contained in whole foods will drastically alter how sugars are absorbed and processed in the body, not to mention provide other nutritional benefits [7].
To make sense of it all, let’s look at the glycemic index.
According to Harvard Health, “The glycemic index is a value assigned to foods based on how slowly or how quickly those foods cause increases in blood glucose levels” [8]. Foods are scaled from 0 – 100, with 0 meaning that no glucose is released (meat, poultry, and fish), meanwhile 100 is the equivalent absorption of consuming pure glucose.
Generally, a Glycemic Index (GI) score of less than 55 is considered low, and optimal for blood sugar management as glucose will be absorbed slowly. 56-69 is considered medium, foods that should be consumed in moderation, and 70 or higher are foods that should be avoided – within reason – due to their tendencies to spike blood glucose rapidly.
Here are some common food examples [9]:
Figure 1. Glycemic Index chart from Healthiack [9].
Alright, so now that we have a clear idea about dietary sugars and how they are absorbed into the bloodstream as glucose, we can shift our focus to the next section, blood glucose levels.
Blood Glucose Levels
Circulating blood glucose is extremely important. We have already discussed that it is the primary fuel source in the body, but it is also the starting substrate for many critical processes, including “glycolysis, citric acid cycle, Cori cycle, glycogenesis, hexose-monophosphate (HMP) shunt, and fatty acid synthesis” [10]. So, yeah, lots of important things.
Simply put, the body needs balanced levels of blood glucose to distribute to different cells and organs as required. For example, the brain “requires a steady supply of arterial glucose for adequate metabolic function” [11]. Low blood glucose levels – otherwise known as hypoglycemia – feature symptoms such as fatigue, pale skin, anxiety, hunger, and an irregular heartbeat, among others [12].
If you are wondering about keto, low carb diets, or fasting, it should be noted that the body can produce glucose in the absence of dietary carbohydrates. Gluconeogenesis, which is discussed in detail in Episode 006 about fasting, and glycogenolysis, are two pathways that make glucose available in these states [11]. So, fear not, blood glucose levels can be maintained without carbs.
On the other side of the coin, elevated blood glucose levels may lead to osmotic nerve damage that results in reduced wound healing, increased inflammation and oxidative stress, and potentially irreversible organ damage [11].
These elevated blood glucose levels, referred to as hyperglycemia, have many common symptoms, which may not show up for varying periods of time. Early symptoms include frequent urination, increased thirst, fatigue, and headaches, meanwhile later signs include fruity-smelling breath, nausea, dry mouth, weakness, and more [13].
Before we expand on diabetes, let’s quickly talk about blood glucose levels. The average, healthy fasting blood glucose concentration (which means that there was no meal within 3-4 hours) is between 80-90 mg/dl which is 4.4-5.0 mmol/L [c]. Meanwhile, after eating, this may rise to 120-140 mg/dl (or 6-7.8 mmol/L). This usually returns to its baseline within two hours.
According to Diabetes.co, there are some ranges used to identify prediabetes and diabetes [14].
Figure 2. Blood glucose levels for diagnosing diabetes, courtesy of Diabetes.co [14].
A quick note on the differences between type 1 and type 2 diabetes. Type 1 is the result of an autoimmune pathology, in which the immune system attacks beta-cells in the pancreas, thereby resulting in a loss of insulin secretion [10]. As we will learn, without insulin, the body cannot distribute blood glucose into cells, thus requiring insulin injections to account for their deficiency. Type 1 is typically experienced in younger patients and accounts for approximately 5% of cases [15].
Type 2, meanwhile, is typically associated with weight gain, obesity, insulin resistance, and progressive metabolic dysregulation [10]. Over time, the body becomes resistant to insulin – the mechanisms of the hormone are not as effective. This means that more insulin is required to promote cells to take up glucose. As a result, cells are starved of energy despite having high levels in blood plasma.
Since excessive sugar intake, particularly added sugars, is correlated with the onset of Type 2 diabetes, this is more reason to be very conscientious of dietary sugar consumption. Diabetes is, after all, the 7th leading cause of death in the US, according to the CDC [16].
Insulin and Glucagon
With an overview of diabetes and blood glucose levels, let’s talk about insulin and glucagon.
As a broad overview, insulin is an anabolic hormone that plays an important role in key metabolic processes, including gluconeogenesis, glycolysis, glycogenesis, glycogenolysis, lipogenesis, and lipolysis [17]. A good summary is that “Insulin’s overall role is to control energy conservation and utilization during feeding and fasting states” [17]. Pretty important stuff.
When we consume carbohydrates, blood sugar levels will increase. In response, the pancreas secretes insulin to signal the cells of the body to absorb the blood glucose for energy or storage [1]. So, yes, if not required for immediate energy use or to replenish glycogen in the muscles or liver, sugars can be stored as fat. Interestingly, insulin receptors have been observed to decrease in obesity and increase in starvation [10]. This becomes important when talking about insulin sensitivity and resistance.
But first, glucagon is another hormone produced by the pancreas [1]. In the case of low blood glucose levels, glucagon stimulates the liver to release stored glucose via gluconeogenesis and glycogenolysis, occurring in the liver and muscles [10].
In essence, insulin helps to lower blood glucose levels by removing glucose from the blood, and glucagon helps to raise blood glucose levels by releasing stored glucose into the blood.
So now, a quick explanation on insulin sensitivity and insulin resistance. Insulin sensitivity is healthy – you want to be insulin sensitive. This means your body is highly responsive to changing blood glucose levels and able to produce and secrete insulin when blood glucose levels rise, particularly after eating carb-rich meals.
Insulin-resistance, on the other hand, is associated with Type 2 diabetes. In this case, insulin does not respond to rising blood sugar levels effectively. Since insulin is limited or insufficient, not enough glucose is removed from the blood and absorbed into cells.
Recall that Type 1 Diabetics cannot produce insulin, so this is why they will have to regularly inject insulin. Without injections, their bodies are unable to absorb blood glucose into the cells. Type 2 Diabetes, meanwhile, is largely treated with lifestyle interventions, including weight loss, exercise, blood sugar monitoring, and dietary interventions. With a healthier lifestyle, insulin sensitivity may improve.
Personal Experience
Alright, at this point, I would quickly like to talk about my own self-experimentation.
I wanted to observe my own blood glucose levels given their importance for health and longevity. Fortunately, I was able to get my hands on a continuous glucose monitor and two regular monitors that require blood from a finger prick. After just over a week of evaluating my own blood glucose levels, here are my observations.
First, I must note that there is definitely an element of uncertainty with these testing devices. My continuous monitor was an older model and may have up to 20% uncertainty. The other two monitors, being fingerpricks, are only capable of showing point-in-time measurements. Constant testing is expensive and undesirable, so there are limitations in my readings.
My continuous monitor usually read lower than the others, so again, there is some uncertainty. For example, on three different occasions, I measured with all three devices at the exact same times, and these were the results:
May 29th, 8:31am, 13 hours fasted, post-workout:
- Continuous Monitor (Freestyle Libre): 4.0 mmol/L
- One Touch: 5.1 mmol/L
- Contour Next One: 5.1 mmol/L
May 29th, 4:02pm, 2 hours post-meal:
- Continuous Monitor (Freestyle Libre): 4.1 mmol/L
- One Touch: 4.7 mmol/L
- Contour Next One: 4.4 mmol/L
May 30th, 8:43am, 14 hours fasted, post-workout:
- Continuous Monitor (Freestyle Libre): 4.9 mmol/L
- One Touch: 5.2 mmol/L
- Contour Next One: 5.3 mmol/L
As you can see, there are some consistencies and positive trends, but it is impossible to know with certainty what my blood glucose levels were.
Next, I was surprised at how little variance I observed. The difference between fasted states (14+ hours) and immediately following carb-heavy meals was rather minimal. Of course, that indicates a good insulin response, so that is encouraging.
My typical levels ranged between 3.6-5.5 mmol/L (or about 65-100 mg/dl), which is within the optimal ranges. Of course, fasted states were lower than postprandial states.
Amazingly, despite testing different foods to see how much of a spike I could induce – by eating white breads and handfuls of chocolates, the highest I ever observed was 6.2 mmol/L (about 110 mg/dl), but it flattened very quickly. Also interesting, is that this specific meal included cherries, cheese, eggs, beef liver, salmon, MCT oil, milk, whey protein powder, and collagen peptides.
I also noticed small spikes during high intensity exercise, which was always done in a fasted state (typically about 12+ hours fasted followed by an hour long workout at moderate to high intensity).
Intuitively, this makes sense because exercise elicits the release of glucose from the liver to fuel muscles, meanwhile hormonal responses such as cortisol spikes may also play a role.
Given this experiment, I feel more assured that I have optimal blood glucose levels for hormonal and cognitive performance, as well as general health and longevity.
So What can you do
First, I must disclaim that I am not a doctor, and this is not medical advice. You are advised to seek out professional medical advice for any concerns, questions, or testing strategies.
To summarize the mechanisms discussed, dietary carbohydrate intake impacts blood glucose levels. As sugar is absorbed, blood glucose levels will rise. On the other end, insulin removes glucose from the blood by distributing it throughout the body. If blood glucose levels are too low, glucagon will promote the release of stored glucose into the blood. Together, these keep blood glucose in balance for optimal levels.
As for recommendations, I do think this is a valuable practice for everyone to monitor their blood glucose levels, even if just a few sample tests. Whether you believe you are at risk for diabetes or not, blood glucose levels and insulin sensitivity are very important and the ability to observe prediabetic levels early can be very valuable in preventing Type 2 Diabetes.
If you are interested in self-testing, it can easily be done, although it can be expensive in some cases. Continuous monitors can often be over $100 and may be good for up to two weeks. Most blood glucose monitors, which use testing strips and finger pricks, cost $40-50 and usually include 10 strips. Additional testing strips are generally between 50 cents and $2 each, so they can be expensive over time.
You can find these devices in any pharmacy or online, such as Amazon. I would recommend talking to a physician or pharmacist for advice.
But without monitoring, everyone should pay attention to any possible symptoms. If you have had underlying symptoms that are generally unexplained, maybe it is worth considering if blood glucose levels are a factor.
Secondly, I recommend that everyone takes time to evaluate their diet and be cognizant of sugar consumption, particularly added sugars and foods with a high glycemic index. Merely educating yourself on the potential impact of dietary choices is a very powerful practice.
Obvious recommendations include obtaining a healthy weight, exercising regularly, and potentially experimenting with a lower-carb diet. But if you still want to enjoy those pastas and potatoes, try cooling them after cooking to increase resistant starches and decrease their glycemic index!
To close off, NBA star Derrick Rose once said “Everyone has their poison, and mine is sugar” [18].
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References
[1] Holesh JE, Aslam S, Martin A. Physiology, Carbohydrates. [Updated 2020 Aug 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459280/
[2] Hantzidiamantis PJ, Lappin SL. Physiology, Glucose. [Updated 2020 Sep 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545201/
[3] Bjarnadottir, A. & Warwick, K. W. (2020, June 26). 56 Different Names for Sugar (Some are tricky). Healthline. Retrieved from https://www.healthline.com/nutrition/56-different-names-for-sugar#1.-Sugar/sucrose
[4] Birt, D. F., Boylston, T., Hendrich, S., Jane, J. L., Hollis, J., Li, L., McClelland, J., Moore, S., Phillips, G. J., Rowling, M., Schalinske, K., Scott, M. P., & Whitley, E. M. (2013). Resistant starch: promise for improving human health. Advances in nutrition (Bethesda, Md.), 4(6), 587–601. https://doi.org/10.3945/an.113.004325
[5] White J. R., Jr (2018). Sugar. Clinical diabetes : a publication of the American Diabetes Association, 36(1), 74–76. https://doi.org/10.2337/cd17-0084
[6] Stanhope K. L. (2016). Sugar consumption, metabolic disease and obesity: The state of the controversy. Critical reviews in clinical laboratory sciences, 53(1), 52–67. https://doi.org/10.3109/10408363.2015.1084990
[7] Freeman, C. R., Zehra, A., Ramirez, V., Wiers, C. E., Volkow, N. D., & Wang, G. J. (2018). Impact of sugar on the body, brain, and behavior. Frontiers in bioscience (Landmark edition), 23, 2255–2266. https://www.bioscience.org/2018/v23/af/4704/fulltext.htm
[8] Glycemic index for 60+ foods. (2020, January 6). Harvard Health Publishing. Retrieved from https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods
[9] Gololici, M. (n.d.). Glycemic index chart. Healthiack. Retrieved from https://healthiack.com/health/glycemic-index-chart
[10] Gurung P, Jialal I. Plasma Glucose. [Updated 2020 Sep 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541081/
[11] Mathew P, Thoppil D. Hypoglycemia. [Updated 2021 Jan 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534841/
[12] Hypoglycemia. (2021). Mayo Clinic. Retrieved from https://www.mayoclinic.org/diseases-conditions/hypoglycemia/symptoms-causes/syc-20373685
[13] Hyperglycemia. (2021). Mayo Clinic. Retrieved from https://www.mayoclinic.org/diseases-conditions/hyperglycemia/symptoms-causes/syc-20373631
[14]Blood sugar level ranges. (2019, January 15). Diabetes.co. Retrieved from https://www.diabetes.co.uk/diabetes_care/blood-sugar-level-ranges.html
[15] Nakrani MN, Wineland RH, Anjum F. Physiology, Glucose Metabolism. [Updated 2020 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560599/
[16] Leading causes of death. (2021, March 1). Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm
[17] Vargas E, Joy NV, Carrillo Sepulveda MA. Biochemistry, Insulin Metabolic Effects. [Updated 2021 Feb 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525983/
[18] Rose, D. (n.d.). Derrick Rose Quotes. Brainyquote. Retrieved from https://www.brainyquote.com/quotes/derrick_rose_541438#:~:text=Derrick%20Rose%20Quotes&text=Everybody’s%20got%20their%20poison%2C%20and%20mine%20is%20sugar.
