Foundations of Metabolic Health
Lifestyle Health Wrap #19 part 1
For this wrap, I provide an introduction to metabolic health and many of the key concepts for understanding metabolic health. As usual, I also share five different research articles in the categories of diet, exercise, sleep, stress, and connection, and they are all related to metabolic health. But because I’ve decided to make this a two-part wrap, in this part I simply share the articles, and in the second part (now posted here) I’ll summarize the research like I usually do.
I hope you learn something, and please let me know if you notice any mistakes or have any feedback about this post.
What is Metabolic Health?
You’ve probably heard the phrase “metabolic health”, but what is it?
To understand the meaning of metabolic health, one must first understand the meaning of metabolism, which refers to the life-sustaining chemical reactions that occur in our bodies and all living things. Metabolism is all about energy; it’s about how the body breaks down food for energy, and how the body uses and stores energy. To have good metabolic health means to have well-functioning biological systems for breaking down food and effectively using and storing the nutrients from food. It’s all about a balance of energy intake and energy output, or what biologists call homeostasis, defined as “the tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes.” Homeostasis is not entirely about balancing energy intake and output, but that’s certainly an important aspect of it.
Thus, to understand metabolic health, one must understand that the body is in a constant state of flux with many different interacting systems and processes that aim to maintain a balance, and metabolism is the term used to describe quite a large portion of those systems and processes. The balancing act of metabolism is particularly obvious when considering the fact that metabolism is often subdivided into catabolism and anabolism.
Catabolism, or a catabolic process, refers to any process wherein large molecules are broken down into smaller parts, typically for energy. This includes the breakdown of carbohydrates from food, and glycogen stored in our muscles, into glucose that can then be transported to cells for energy. “Burning fat” for energy is also an example of catabolism. If you don’t eat enough protein, your body may start breaking down muscle to access amino acids that it needs for cellular repair and other processes, and that is another example of catabolism.
Anabolism refers to the building of larger molecules from smaller molecules, which is needed for growth, tissue repair, and the natural cycles of cellular turnover that occur throughout our bodies. When you get interested in working out and growing muscle, you start seeing the word “anabolic” being used everywhere (e.g., “anabolic steroids” and “anabolic supplements”) because gaining muscle mass is the prime example of an anabolic process.
Metabolic rate is used to refer to the rate at which our bodies use energy. The core component of metabolic rate is called basal metabolic rate (BMR), and this is the minimum amount of energy one’s body needs to function at rest. These metabolic rates are typically measured in calories per day. BMR accounts for most of the energy our bodies use (i.e., most of our metabolic rate) and the rest of our energy expenditure occurs through the energy needed to break down food and to move.
At this point you might be thinking, ok, I get metabolism, but what is metabolic health? Believe it or not, there is not really a consensus definition. Metabolic health researchers acknowledge this in this paper published in Nature and this paper from the Journal of Metabolic Syndrome and Related Disorders. But, there is a general consensus about what the key biomarkers to assess metabolic health are, which I cover in the next section…
Indicators of Metabolic Health
The key indicators for assessing metabolic health include blood sugar, triglycerides, cholesterol, blood pressure, and waist circumference. These key indicators of metabolic health come from the National Heart, Lung, and Blood Institute’s webpage about metabolic syndrome. When at least 3 of these biomarkers are not in a healthy range, one can get diagnosed with what is called metabolic syndrome.
Metabolic syndrome is a group of conditions that together raise your risk of coronary heart disease, diabetes, stroke, and other serious health problems. Metabolic syndrome is also called insulin resistance syndrome.
That page goes on to say that “you may have metabolic syndrome if you have three or more of the following conditions”: a large waistline, high blood pressure, high blood sugar levels, high blood triglycerides, and low HDL cholesterol.
Blood sugar: Glucose is your body's primary energy source. When you eat, your blood sugar rises; this signals your pancreas to release insulin, which enables your cells to take in glucose for energy or storage. High blood sugar (hyperglycemia) can lead to type 2 diabetes, nerve damage, and heart problems. Low blood sugar (hypoglycemia) can cause weakness, dizziness, and even seizures. Excess food consumption and high body fat, but also poor sleep, and sedentary behavior, can all contribute to the development of insulin resistance, which is when the body doesn’t respond appropriately to the release of insulin. Among other effects, insulin resistance, also referred to as poor insulin sensitivity, eventually results in elevated blood sugar levels because it is insulin that enables the clearance of blood sugar out of the circulatory system and into our cells for storage and use. Chronic insulin resistance becomes referred to as prediabetes, which if not treated with lifestyle changes (i.e., improving one’s diet, increasing physical activity, managing stress, and/or improving sleep) eventually results in type 2 diabetes.
To learn more about insulin resistance and type 2 diabetes, click those hyperlinks to go to some great pages about these things by the Cleveland Clinic.
Learn more: Long-term remission of type 2 diabetes through intense lifestyle modification program – A case series
Triglyceride Levels: Triglycerides are a type of fat stored in your body's fat cells (adipose tissues). High levels of circulating triglycerides can contribute to the buildup of plaque in your arteries, a process called atherosclerosis. This plaque narrows your arteries, making it harder for blood to flow through, increasing the risk of heart attack and stroke. Elevated triglycerides tend to be a result of excess food consumption. When you consume more calories than your body needs, it converts those extra calories into triglycerides. Moreover, insulin resistance, which can result from excess food consumption, can lead to excess production of triglycerides by the liver, leading to their buildup in the blood
Cholesterol: cholesterol is a necessary component of cell membranes and essential for the synthesis of hormones. Our bodies transport cholesterol in the bloodstream with the help of lipoproteins, particularly high-density lipoprotein (HDL) and low-density lipoprotein (LDL) (there are others though too). Having high levels of high-density lipoprotein cholesterol (HDL-C) is generally a positive marker of metabolic health, whereas high levels of LDL-C are generally not. HDL helps remove excess cholesterol from your bloodstream, transporting it to the liver for breakdown and removal from the body, reducing the risk of plaque buildup in your arteries. LDL lipoproteins transport cholesterol to cells throughout the body. If there's too much LDL cholesterol though, it can build up in your artery walls, forming plaque that leads to heart disease. Generally, it is the ratio of total cholesterol to HDL cholesterol that is considered the best indicator of healthy cholesterol levels, with a lower ratio, optimally about 3.5:1, being better than a high ratio (a lower ratio means a relatively high proportion of cholesterol in the blood is HDL-C). Research about HDL and LDL cholesterol is sometimes hotly debated and can get complicated. So just know that this is more complicated than I’ve described it here.
Blood Pressure: High blood pressure, also called hypertension, puts extra strain on your heart and blood vessels, increasing the risk of heart attack, stroke, and kidney disease. High blood pressure reflects metabolic health for several reasons. For one, it can reflect insulin resistance because insulin helps blood vessels relax and dilate to regulate blood flow. When cells become resistant to insulin, blood vessels don't respond as well, which can lead to constricted blood vessels and increased blood pressure. Moreover, blood pressure can be raised as a result of elevated stress hormones triggered by metabolic problems and chronic inflammation associated with metabolic dysfunction. Finally, carrying excess weight, especially around your abdomen, puts extra strain on your heart and blood vessels, which can lead to high blood pressure.
Waist Circumference: Excess abdominal fat (visceral fat) is a key indicator of poor metabolic health and it is a greater risk factor for heart disease than excess fat in other areas of the body. The build-up of excess abdominal fat can essentially result in all of the negative indicators covered above (i.e., the development of insulin resistance, elevated triglyceride levels, increased LDL-C levels, and high blood pressure).
We’re not doing alright
With increasingly high levels of obesity and diabetes, metabolic health has become a major focus of public health and healthcare because poor metabolic health is costing us and killing us. In the following study, researchers used nationally representative data from 2009-2016 and the most recent guidelines (in 2019) for optimal waist circumference, fasting glucose, blood pressure, triglycerides, and HDL cholesterol to create criteria for optimal metabolic health. Their analysis found that only 12% of Americans have optimal metabolic health. That means only about 1 in 9 people in the US have optimal metabolic health. This is not good.
Prevalence of Optimal Metabolic Health in American Adults: National Health and Nutrition Examination Survey 2009–2016 — Healthline summary
Podcast Rec
Finally, I’d like to share this Doctor Mike podcast featuring Dr. Jason Fung, which is what inspired me to focus this wrap on metabolic health. Their discussion about diet, diabetes, fasting, and insulin resistance is a fantastic way to learn more about these topics. Despite both being highly educated doctors, their discussion of research is relatively easy to understand. If you’re at all like me, I think you’ll enjoy and probably learn a lot from this podcast.
Or listen/watch on Spotify or listen on Apple Podcasts:
Spotify: Debating Dr. Jason Fung on Calories & Insulin
Apple Podcasts: Debating Dr. Jason Fung on Calories & Insulin
That’s the bulk of it for part 1 of wrap #19.
Below are the usual sections on diet, exercise, sleep, stress, and connection, which I will cover in part 2, in due time.
Stay Tuned for Part 2
Edit: now available to read here:
Metabolic Health Research
If you didn’t read part 1 of this wrap, I recommend it. Check it out here: Foundations of Metabolic Health.
DIET | EXERCISE | SLEEP | STRESS | CONNECTION
Diet
Cooking Well with Diabetes: A Healthy Cooking School for Diabetes Prevention and Management | June 14, 2024
N = 1574 adults from 59 predominantly rural Texas counties
Diet Education Intervention
Exercise
Physical activity in relation to metabolic health and obesity: The Feel4Diabetes study | June 19, 2024
N = 2848 men and women from families at risk of the development of diabetes
Prospective Cohort Study
Sleep
Ad libitum Weekend Recovery Sleep Fails to Prevent Metabolic Dysregulation during a Repeating Pattern of Insufficient Sleep and Weekend Recovery Sleep | March 18, 2019
N = 36 healthy, young adults
Randomized Controlled Trial
Stress
Improvement in symptoms of anxiety and depression in individuals with type 2 diabetes: retrospective analysis of an intensive lifestyle modification program | October 22, 2024
N = 1061 type 2 diabetic patients (177 prediabetic)
Retrospective Cohort Study
Connection
The Role of the Perceived Neighborhood Social Environment on Adolescent Sedentary Behavior and Physical Activity: Findings from Add Health | February 19, 2024
N = 6504 adolescents (aged 15.4 ± 0.03 years) who participated in the National Longitudinal Study of Adolescent Health
Retrospective Cohort Study
Disclaimers:
This newsletter provides health information and research for educational purposes only. It is not a substitute for professional medical advice. Consult a healthcare professional for guidance on your health-related decisions. We are not medical professionals.
Google’s AI service Google Gemini was used to assist with the writing of this article. There may be full sentences and/or clauses that were produced by Google Gemini.