This glossary explores some of the most commonly used terms in metabolic health, drawing on the latest research in glucose management, insulin resistance, and preventative health interventions. If you’re interested in learning more, browse through our catalog of educational articles on a range of metabolic science topics.
A
A1C (also hemoglobin A1C or HbA1c)
A1C is a snapshot of your average blood sugar levels over the past three months. It works by measuring the percentage of your hemoglobin — a protein in red blood cells that carries oxygen — that is coated with sugar (glucose). The higher your A1C level, the worse your blood sugar control and the higher your risk of developing insulin resistance, prediabetes, and diabetes. While the A1C test can be a useful diagnostic tool, it has limitations. It doesn’t differentiate between high glucose levels caused by diet, exercise, sleep, stress, and other medical/lifestyle factors, and it doesn’t provide a clear picture of day-to-day (or even hour-to-hour) glucose variability. Continuous glucose monitoring, on the other hand, can better guide individuals in understanding their metabolic health and making adjustments in lifestyle or diet to stabilize glucose levels.
Try our A1C calculator here.
Androgen
Androgens are often referred to as “male hormones,” but they play critical roles in both men’s and women’s health. These hormones, which include testosterone, are primarily involved in the development of male traits and reproductive activity. In women, androgens are produced in the ovaries, adrenal glands, and fat cells and are crucial for bone strength and libido. Imbalances in androgen levels can lead to various health issues, such as polycystic ovary syndrome (PCOS) and decreased fertility in women or decreased muscle mass and low energy in men — all of which can lead to glucose dysregulation and metabolic health concerns.
Anti-inflammatory diet
Inflammation is your body’s response to injury or infection, but chronic inflammation is like an uncontrolled wildfire that can make your cells insulin-resistant, trigger weight gain, and lead to heart health problems. An anti-inflammatory diet is like the firefighter of your body's ecosystem, designed to reduce chronic inflammation and promote overall health. This diet emphasizes whole and unprocessed fruits, vegetables, nuts, whole grains, and healthy fats known to reduce inflammation in the body while avoiding pro-inflammatory foods like added sugar, refined grains, processed meat, and alcohol.
B
Basal metabolic rate (BMR)
Basal metabolic rate, or BMR, is the amount of energy or calories your body needs to maintain its basic functions — like breathing, circulation, and cell production — while at rest. It’s like the idle power requirement for your body to keep all its systems running before considering any additional activities. Factors such as age, sex, weight, and muscle mass can all influence your BMR, and understanding your BMR can empower you to better manage your weight and overall health, as it provides a baseline for how many calories you need to consume to support your lifestyle. That said, BMR does not account for other key factors — like glucose levels, glucose variability, and your body’s unique responses to diet and lifestyle — that play a significant role in metabolic health.
Body composition
Body composition goes beyond your body weight (the number on the scale) and covers the full spectrum of what your body is made of, including fat, muscle, bone, and water. Unlike body weight, which doesn't distinguish between fat and muscle, body composition can give you a clearer picture of your health and fitness level. For instance, two people may weigh the same but have different body compositions, with one having more muscle and less fat — which can have significant implications for insulin resistance and metabolic health (in general, the higher proportion of fat mass to lean mass, the worse your insulin resistance will be). Knowing your body composition can be empowering and allow you to tailor your diet and exercise regimen to achieve healthier body fat levels and improve overall wellness.
Biphasic glucose curve
Picture your body’s response to sugar as a two-act play — that’s the essence of the biphasic glucose curve. After you eat, your blood sugar levels rise, and your pancreas quickly releases insulin, leading to the first peak, which only lasts a few minutes. Then, after a decrease in glucose levels, , your body releases more insulin, leading to a second, smaller rise that lasts for a longer period of time. People who display biphasic curves tend to have better insulin sensitivity and greater metabolic health. So if you’re tracking your glucose levels with a CGM and notice a biphasic curve, don’t fret!
C
Calories in, calories out (CICO)
The concept of calories in, calories out (CICO) is based on the idea that weight management hinges on the balance between the calories you consume through food and drink and the calories your body expends for functions and activities. If you consume more calories than you expend, the excess is stored, often leading to weight gain. On the other hand, consuming fewer calories than your body needs can lead to weight loss. While useful in some contexts, CICO has limitations. It doesn’t factor in the quality of the calories and individual metabolic factors, which play a significant role in metabolism. Eating 200 calories of refined carbs (e.g., white bread) is not the same as eating 200 calories of vegetables and lean protein — both trigger significantly different glucose responses, which can impact your hunger levels and satiety.
Carbohydrate intolerance
Carbohydrate intolerance or sensitivity is a term used to describe a disrupted glucose and insulin response to eating carbs, typically after eating a keto diet. You can think of carbohydrate intolerance as a form of insulin resistance. It occurs because the keto diet makes your body more efficient at using fat as its primary fuel source, and less efficient at using carbs. Carb intolerance may involve uncomfortable symptoms such as bloating, gas, and abdominal pain. The good news is that it’s temporary. As you introduce carbs back into your diet, start low and increase your daily carb intake gradually. Start with small servings and high-fiber, low-glycemic index fruits, vegetables, and whole grains to minimize glucose spikes.
Cardiometabolic health
Cardiometabolic health is a comprehensive term that encompasses the health of your heart and metabolic systems. Think of it as the harmony between your cardiovascular system, which includes your heart and blood vessels, and how well your metabolism is working (clinically measured via high cholesterol, high fasting blood glucose, a large waistline, and high blood pressure). Poor metabolic health has a direct impact on your cardiometabolic health and vice versa. Optimal cardiometabolic health means a reduced risk of heart disease, stroke, diabetes, and other related conditions. Achieving and maintaining good cardiometabolic health involves a balanced diet, regular physical activity, managing stress, and avoiding smoking and drinking too much alcohol.
Circadian rhythm
Your circadian rhythm is essentially your body’s internal clock, running in the background to regulate cycles of sleepiness and alertness over a 24-hour period. Influenced by light and darkness, this natural time-keeping system helps dictate your sleep patterns and eating windows as well as critical processes like hormone release and glucose metabolism. Living according to your circadian rhythm can enhance sleep quality, energy levels, and overall metabolic health. Here are some tips to keep in mind: maintain a consistent sleep schedule, eat earlier in the day (and with some form of time-restricted eating built in), and get exposure to natural light early in the morning.
Continuous glucose monitoring (CGM)
Continuous glucose monitoring, or CGM, is like having a personal assistant constantly monitoring your blood sugar levels, providing real-time insights without the need for frequent finger-prick tests. This technology involves a small, painless sensor worn under the skin that measures glucose levels in the interstitial fluid — the fluid between your cells. It offers a detailed picture of how your glucose levels fluctuate throughout the day and night, empowering you with data to make informed decisions about diet, exercise, and lifestyle to manage or improve your metabolic health.
Cortisol
Cortisol, the “stress hormone,” plays a key role in your body’s stress response. Produced by the adrenal glands, it’s like your body’s built-in alarm system, preparing you to either stand your ground or take flight in challenging situations. While essential in short bursts for survival, chronic high levels of cortisol can lead to various metabolic health issues, such as weight gain, insulin resistance, high blood pressure, and a weakened immune system. Learning to manage stress through techniques like mindfulness, exercise, and adequate rest can help keep your cortisol levels balanced and promote overall well-being.
D
Dietary supplement
Dietary supplements are products intended to supplement the diet, containing one or more dietary ingredients, including vitamins, minerals, herbs, amino acids, and enzymes. They come in various forms, such as tablets, capsules, powders, and liquids. Some research has explored the effects of certain dietary supplements on glucose levels and insulin resistance, with promising results. While supplements can provide nutrients that might be missing from the diet, they’re not a silver bullet* and shouldn’t replace a metabolically balanced diet.
*Follow your healthcare provider’s advice if they request you take a supplement (e.g., you’re vegan and missing certain vitamins and minerals; you’re deficient in vitamin D) to fill any nutritional gaps or because you have a specific medical condition.
E
Estrogen
Estrogen is a key hormone in women’s health, playing a vital role in the development and regulation of the female reproductive system and secondary sexual characteristics. Though present in both sexes, estrogen levels are significantly higher in women, influencing menstrual cycle regulation, pregnancy, and menopause, along with bone density, skin health, and mood. Estrogen also promotes insulin sensitivity and glucose regulation, which is why insulin sensitivity is highest during the follicular phase of the menstrual cycle (estrogen levels peak). During the luteal phase, however, progesterone levels are high and estrogen levels are low, resulting in temporary insulin resistance. It’s best to avoid high-carb and high-sugar foods during the luteal phase.
F
Fasting glucose levels
See "glucose" entry below.
Fasting insulin levels
See "insulin" entry below.
Fertility
Fertility is the natural capability to produce offspring. In women, it involves a complex interplay of hormones leading to the release of an egg (ovulation), and in men, it involves the production of viable sperm. There are a number of variables that can affect fertility, including age, lifestyle, health conditions (like PCOS), and exposure to environmental toxins. Less well-known is that insulin resistance, a condition where your body’s cells stop responding properly to the hormone insulin, can trigger a cascade of events that promote infertility in both men and women. Improving insulin sensitivity through exercise, proper sleep, and stress management, as well as minimizing glucose spikes by prioritizing whole foods/minimizing sugar, may help you avoid infertility related to insulin resistance.
Fiber
Fiber is the unsung hero in your diet, playing critical roles in digestive health, blood sugar regulation, and heart health. Found in whole foods like fruits, vegetables, whole grains, and legumes, fiber comes in two types: soluble and insoluble. Soluble fiber dissolves in water to form a gel-like substance that helps lower blood glucose and cholesterol levels. Insoluble fiber, on the other hand, does not dissolve, adding bulk to your stool and helping prevent constipation. By fostering a healthy gut environment and offering a sense of fullness after meals. Fiber is a powerful ally in fostering a healthy gut microbiome, improving satiety, stabilizing glucose levels, and even promoting weight loss.
Food desert
A food desert is an area with limited access to affordable and nutritious food, particularly fresh fruits and vegetables. These areas are often found in urban and rural settings, where residents might have to travel long distances to find a supermarket or grocery store. Living in a food desert can promote diets heavy in processed convenience foods that are high in calories but low in nutritional value and fiber, contributing to health disparities such as obesity and diabetes.
Food as Medicine
Food as Medicine programs are rooted in the idea that dietary choices play a critical role in maintaining health and preventing disease. Though once a fringe concept, “food as medicine” now has significant clinical weight, with conventional healthcare systems providing programs that allow doctors to prescribe whole fruits, vegetables, and other nutrition interventions to people who are experiencing chronic disease or food insecurity. In the context of our ongoing metabolic health crisis, Food as Medicine programs could prevent an estimated 296,000 cases of cardiovascular disease (including heart attacks and strokes) and save an estimated $39.6 billion in healthcare spending.
Fructose
Fructose is a type of simple sugar found naturally in fruits, honey, and vegetables, and is also a component of table sugar (sucrose) and high-fructose corn syrup, used as sweeteners in many processed foods. While fructose in whole foods (e.g., fruits) comes with beneficial nutrients and fiber, its concentrated and refined forms in sweetened foods and beverages (high-fructose corn syrup, agave) can contribute to weight gain, insulin resistance, and liver disease if you consistently eat too much of it.
G
Ghrelin
Ghrelin is a hormone that acts like as body’s hunger signal. Produced mainly in the stomach, it tells your brain it’s time to eat. Secretion of this “hunger hormone” increases before meals and decreases after eating. Beyond its role in regulating appetite, ghrelin also plays a part in energy management and can even impact sleep and mood. Understanding ghrelin’s effects can help you better listen to your body’s cues for hunger and fullness, supporting healthier eating habits and overall well-being.
GLP-1 agonist
GLP-1 agonists (sold under names like Ozempic, Wegovy, Rybelsus) are drugs that mimic the action of the naturally occurring hormone GLP-1, which plays a crucial role in blood sugar regulation. GLP-1 increases insulin release in response to high blood sugar levels, slows down stomach emptying, promotes the health of your pancreatic beta cells (which secrete insulin), and reduces appetite. Used primarily in the treatment of type 2 diabetes, GLP-1 agonists are now popularly prescribed as a weight loss drug in non-diabetics. However, taking them without the proper lifestyle interventions (in the areas of diet, exercise, sleep, and stress) does not lead to long-term weight loss or weight loss after stopping the drug.
Glucose (also fasting glucose levels)
Glucose, a simple sugar, is your body’s preferred energy source. It powers the cells of your body, much like gasoline powers a car. Glucose is derived from the foods you eat and is crucial for your brain and muscles to function optimally. Normal fasting blood glucose levels — measured after an overnight fast — are typically between 70 and 100 mg/dL (3.9 and 5.5 mmol/L). Maintaining glucose levels within this range is vital for metabolic health, as consistently high levels can lead to insulin resistance and diabetes, while levels that are too low can cause hypoglycemia.
Glucose intolerance
Glucose intolerance is a condition in which the body struggles to process glucose effectively, leading to higher-than-normal blood sugar levels after eating. It’s often seen as a precursor to type 2 diabetes and indicates a risk for developing metabolic syndrome and cardiovascular disease. Managing glucose intolerance involves lifestyle changes such as adopting a balanced diet, regular physical activity, and maintaining a healthy weight to improve the body’s ability to use glucose efficiently and prevent the progression to diabetes.
Glucotype
“Glucotype” is a term coined by researchers to describe an individual’s unique blood glucose responses to different stimuli. It captures the idea that people can experience different patterns of glycemic response to the same foods, influenced by factors like genetics, lifestyle, and even the microbiome (gut bacteria/health). By understanding how your specific body reacts to different foods via continuous glucose monitoring, you can then make personalized dietary and lifestyle interventions to improve blood sugar control and reduce your risk of developing insulin resistance, diabetes, and metabolic syndrome.
Glycemic index
The glycemic index (GI) is a scale that ranks carbohydrates in foods according to how they affect blood glucose levels. In other words, it’s a guide to help you understand how quickly or slowly a food can cause your blood sugar to rise. Foods are scored on a scale from 0 to 100, with higher values indicating foods that cause a rapid spike in glucose levels. Choosing foods with a low to moderate GI can help manage blood sugar levels, contributing to better energy balance and reducing the risk of type 2 diabetes and heart disease. However, the glycemic index is limited in that it doesn’t tell you how much your blood sugar increases, so a food with a high GI may not actually spike your glucose levels into an unhealthy range (e.g., watermelon, which has a GI of 76 — high — but is mostly made up of water).
Glycemic load
Glycemic load (GL) takes the glycemic index concept one step further by considering the amount of carbohydrates in a serving of food along with the GI value. It provides a more complete picture of how a food can affect blood sugar levels. While the GI measures how quickly a carbohydrate turns into glucose, the GL measures how much glucose a serving of that food delivers. Understanding both the quality (GI) and quantity (GL) of carbohydrates consumed can offer a more nuanced approach to diet and blood sugar management. GL is calculated by multiplying the grams of carbohydrate per serving by the glycemic index, then dividing by 100. Foods can be categorized as low GL (0-10), moderate GL (11-19), or high GL (>20).
Glycogen
Glycogen is your body’s stored form of glucose — i.e., glucose that’s tucked away mainly in your liver and muscles for when you need a quick energy boost and there’s not enough glucose circulating in your bloodstream. Put another way, it’s like the body’s backup battery. When blood glucose levels drop, such as between meals or during exercise, glycogen is broken down into glucose and released into the bloodstream to maintain your energy levels. This storage-and-release system is crucial for managing energy levels efficiently, especially during physical activity or in between meals.
Glycomark test
The glycomark test is a specific blood test that provides information about blood sugar control over the short term. It measures the levels of 1,5-anhydroglucitol (1,5-AG) in the blood. This test is particularly useful for detecting recent episodes of hyperglycemia (high blood sugar) and glycemic variability in people with diabetes. Since 1,5-AG levels decrease when blood sugar spikes, the glycomark test can complement other measures like A1C tests to give a more complete picture of glucose control, ultimately guiding you in making preventative lifestyle and diet choices.
H
Healthspan
Healthspan is the portion of your life that you spend in good health, free from chronic diseases or disabilities that can limit your day-to-day activities. It goes beyond lifespan (the number of years you live) and emphasizes the quality of those lived years and your ability to enjoy a healthy life and continue doing the things you love into old age. Improving healthspan involves a combination of good nutrition, regular physical activity, stress management, good sleep, and preventive metabolic health practices aimed at extending the years you live in good health rather than just extending life itself.
Health halo
The health halo refers to the perception that a particular food, product, or diet is healthier than it actually is, often due to clever marketing, packaging, or an association with certain health trends. This effect can lead consumers to overestimate the nutritional benefits of a product, potentially leading to overconsumption or misguided choices that don’t align with their health goals. For example, foods labeled as “organic,” “natural,” or “gluten-free” might be perceived as inherently healthier, despite their actual nutritional content.
Hemoglobin A1C
See "A1C" entry above.
High-fructose corn syrup
High-fructose corn syrup (HFCS) is a sweetener made from corn starch that has been processed to convert its glucose into fructose. It’s a common ingredient in many processed foods and beverages because it’s inexpensive, sweet, and easy to blend. It’s often used under other names like glucose syrup, corn syrup, isoglucose, tapioca syrup, and crystalline fructose. Though research is inconclusive, HFCS has come under scrutiny for its role in accelerating the obesity epidemic and metabolic conditions like type 2 diabetes. Ultimately, HFCS, much like other refined added sugars that lack fiber, vitamins, and minerals, provides empty calories and can lead to weight gain and an increased risk of diabetes and heart disease when you consume too much of it.
Hyperglycemia
Hyperglycemia is the technical term for high blood sugar levels. It occurs when your body has too much glucose in the bloodstream. This is sometimes an acute result of eating a high-carb or high-sugar meal, but it can also mean that your cells aren’t properly responding to the hormone insulin, which lowers blood sugar levels (also known as insulin resistance). Other factors like dehydration, illness, exercise, PCOS, genetics, meal timing, and an unhealthy diet can all lead to hyperglycemia. Symptoms can include frequent urination, increased thirst, and fatigue. If left unchecked, hyperglycemia can lead to serious complications like diabetic ketoacidosis or chronic conditions affecting the heart, eyes, and nerves.
Hypoglycemia
Hypoglycemia, or low blood sugar, occurs when the glucose level in your blood drops below normal (70 mg/dL or 3.9 mmol/L). Common causes include certain diabetes medications, menopause, thyroid disorders, insulin resistance, PCOS, missing meals, or exercising more than usual without eating additional calories to provide extra glucose. Symptoms can range from hunger, sweating, and trembling to more serious effects like confusion, dizziness, and even loss of consciousness. If you wear a continuous glucose monitor to track your glucose levels, you may experience what's known as "compression hypoglycemia," an error caused by compression of the sensor.
I
Inflammation
Inflammation is your body's natural response to injury or infection, a protective measure designed to heal and restore. Picture it as the body's emergency repair crew rushing to the scene where harm has occurred. While acute inflammation is beneficial — think of the swelling and redness that comes with a cut — chronic inflammation can become a silent adversary, lurking beneath the surface. When the inflammatory response doesn't shut off, it can contribute to a host of chronic diseases, including heart disease, diabetes, and arthritis, making the management of inflammation through lifestyle choices like diet, exercise, and stress reduction crucial for long-term health.
Intermittent fasting (also time-restricted eating)
Intermittent fasting, or time-restricted eating, is a dietary approach that cycles between fixed periods of eating and fasting. This method can range from fasting for several hours each day (i.e., an 8-hour eating window and 16-hour fasting window) to fasting on certain days of the week (i.e., unrestricted caloric intake 5 days of the week followed by restricted caloric intake 2 days of the week). By limiting your eating to a specific window, you give your body a break from digesting food, which affects circadian rhythms and may lead to improved insulin sensitivity, cardiometabolic health, weight loss, and even longer lifespan/healthspan. Learn more about considerations of intermittent fasting if you're a woman, and how to safely exercise and intermittent fast.
Insulin (also fasting insulin levels)
Insulin is a hormone produced by your pancreas, acting as the key that allows glucose from the food you eat to enter your body’s cells to be used as energy. Without insulin, glucose stays in the bloodstream, leading to high blood sugar levels. When your cells become desensitized to the effects of insulin, you have a condition known as insulin resistance. While glucose testing has been widely researched, the interpretations of fasting insulin levels, which reflect how much insulin your body is producing in a resting state, are not definitive and there is not a robust medical consensus on diagnostic ranges.
Insulin resistance
Insulin resistance is when your cells become desensitized to the effects of the hormone insulin. In other words, they start ignoring the signal insulin sends out to let glucose into your cells. Think of it as a miscommunication where the cells have turned down the volume of insulin’s message, causing the pancreas to pump out even more insulin to be heard. This condition is a stepping stone to prediabetes and type 2 diabetes, as it can cause blood sugar levels to rise for unhealthy lengths of time. Some factors that contribute to insulin resistance include excess weight, inactivity, and a diet high in sugar and processed foods. Counteracting insulin resistance involves lifestyle changes like diet, exercise, and sometimes medication, aiming to retune the body’s response to insulin.
K
Keto diet
The keto (ketogenic) diet is a high-fat, low-carbohydrate eating plan designed to trigger a metabolic state known as ketosis. In ketosis, your body, running low on its usual fuel source — glucose from carbohydrates — starts burning fat for energy instead, producing molecules called ketones in the process. This diet has a number of metabolic health benefits: it can help stabilize glucose levels, reverse insulin resistance, and support weight loss. However, keto diets tend to be protein- and fat-heavy, so you’ll need to make sure you’re still eating a wide array of vegetables to ensure you’re getting enough fiber and micronutrients.
Ketones
Ketones, or ketone bodies, are chemicals made in your liver when there’s not enough insulin in your body to turn glucose into energy. Your body then starts burning fat instead, creating ketones as a by-product of this process. This is the basis of the ketogenic diet, which aims to induce a state of ketosis by restricting carbohydrate intake, forcing the body to use fat as its primary fuel source. While ketones can serve as an alternative energy source for many cells, especially in the brain, it’s important to monitor and manage ketone levels if you’re on a ketogenic diet, as well as making sure you’re eating enough fiber.
L
Leptin (and leptin resistance)
Leptin is often referred to as the “satiety hormone.” It helps regulate appetite so you don’t overeat. Produced by fat cells, leptin communicates with your brain — specifically the hypothalamus — to signal that you have enough energy stored in your fat cells and don’t need to eat more. However, if you continuously overeat, you may develop a condition known as leptin resistance, where your brain doesn’t receive this message effectively. This leads you to eat more than necessary, which can contribute to weight gain. Overcoming leptin resistance involves portion control and eating highly satiating foods rich in protein and fiber.
Lifespan
Lifespan represents the maximum number of years an individual can live. It’s the full length of an individual’s life from birth to death. While genetics play a key role in determining lifespan, environmental factors, lifestyle choices, and advances in healthcare and medicine have significantly contributed to extending the population’s average lifespan over time. While increased lifespan or longevity is often a metric of wellness, it doesn’t mean you’re actually spending those additional years in good health. That’s where healthspan comes in. Healthspan (see above) emphasizes the importance of spending your years free from chronic pain, disease, and discomfort, and with enough physical and mental energy to do the things you live.
Lipid panel
A lipid panel is a blood test that measures the levels of various fats in the bloodstream. It typically includes measurements of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides. This panel helps assess the risk of developing cardiovascular disease and can help guide decisions about interventions to reduce this risk. HDL cholesterol and triglycerides are also two of the clinical markers of metabolic health, so nderstanding your lipid panel results can be a key factor in managing cardiometabolic health.
M
Macronutrient
Macronutrients are the nutrients that your body needs in large amounts to provide energy and support overall health and function. They include carbohydrates, proteins, and fats, each playing a unique role in the body. Carbohydrates are the body’s main energy source (glucose), proteins are essential for growth and repair, and fats provide a concentrated source of energy and are vital for hormone production and nutrient absorption. Proteins, fats, and fiber are also critical for satiety and minimizing glucose spikes. Learn how to balance your macronutrients for a metabolically healthy plate here.
Mediterranean diet
The Mediterranean diet is inspired by the eating habits of the countries bordering the Mediterranean Sea. It’s naturally good for metabolic health since it’s rich in vegetables, fruits, whole grains, beans, nuts and seeds, and extra-virgin olive oil, with moderate consumption of fish, poultry, and dairy, and limited intake of red meat and sweets. Research indicates it may have cardiovascular benefits — including lowering your risk of heart disease, diabetes, and other chronic conditions — as well as benefits for your glucose levels and weight. Best of all, it’s centered around principles of healthy eating, rather than dietary rules and restrictions.
Menopause
Menopause marks the end of a woman’s menstrual cycle. More specifically, menopause occurs when you haven’t had a period for 12 consecutive months. It usually occurs in a woman’s late 40s to early 50s and is a natural biological process that signifies the end of fertility. Menopause comes with various physiological changes due to decreased levels of the hormones estrogen and progesterone, leading to symptoms like hot flashes, night sweats, mood changes, and changes in metabolic health. The decrease in estrogen, in particular, may also promote insulin resistance and lead to elevated glucose levels. All of these changes can lead to changes in body composition (more abdominal fat) and reduced muscle mass.
Metabolic age
Metabolic age is a comparative number that indicates your metabolic health compared to the average for your chronological age group. It’s determined by analyzing your basal metabolic rate (BMR) — the amount of energy (calories) your body burns at rest — and comparing it to the BMR average of your age group. If your metabolic age is lower than your chronological age, it suggests a healthier, more efficient metabolism. Conversely, a higher metabolic age might indicate the need for lifestyle changes to improve metabolic health. While useful, metabolic age leaves out important inputs like diet, exercise, sleep, and stress, all of which have a large impact on your metabolic health. As an alternative, consider metabolic healthspan.
Metabolic conditioning
Metabolic conditioning, often abbreviated as MetCon, is a moderate-to-high-intensity workout plan designed to improve metabolism efficiency. These workouts, typically 20 minutes or less, target specific energy systems (metabolic pathways) in the body, which can help strengthen them, improve endurance/stamina, and allow you to overcome a fitness plateau. While research is limited, MetCon workouts may also improve insulin sensitivity and body composition.
Metabolic flexibility
Metabolic flexibility is the ability of your body to seamlessly switch between burning different types of fuel — primarily carbohydrates and fats — based on availability and demand. This flexibility is crucial for maintaining energy balance and optimal health. High metabolic flexibility means your body can efficiently use whatever energy source is most available, which is beneficial for weight loss, body composition, brain health, exercise performance, and reducing the risk of metabolic diseases.
Metabolic health
Metabolic health describes how efficiently your body’s metabolism (i.e., how your body produces and uses energy to stay alive) is working. In a diagnostic context, it is measured via five markers: waist circumference, fasting blood glucose, systolic blood pressure, triglycerides, and HDL cholesterol. Having abnormal levels in three of these five categories means you have metabolic syndrome or insulin resistance syndrome, which increases your risk of developing diseases such as type 2 diabetes, heart disease, and stroke. However, this clinical definition of metabolic health doesn’t give us the complete picture of what it is. Metabolic health is a spectrum — there’s a wide gulf between being in good health and having metabolic syndrome. Using a CGM is a great way to understand where you are on this spectrum because CGMs let you see your glucose variability (i.e., a day-to-day picture of your health, as opposed to a broad snapshot).
Metabolic syndrome
Metabolic syndrome is defined as having abnormal levels in at least three of the five markers of metabolic health: waist circumference, fasting blood glucose, systolic blood pressure, triglycerides, and HDL cholesterol. Metabolic syndrome increases your risk of developing diseases such as type 2 diabetes, heart disease, and stroke, and affects a staggering 33% of Americans. Lifestyle interventions like diet, exercise, stress management, and sleep are key strategies in preventing or managing metabolic syndrome.
Metabolism
Metabolism encompasses all the chemical reactions in your body that convert food into energy and keep you alive. This complex system of biochemical processes is tightly controlled to ensure that your body maintains homeostasis (biological balance). Each of the three key macronutrients (carbs, proteins, and fats) is metabolized differently in the body, with the end goal of providing glucose to your cells to use as energy. Whereas the term metabolism refers to the sum of all of these processes and reactions, the efficiency of your metabolism is known as metabolic health (see above).
Microbiome
The microbiome refers to the complex community of microorganisms, including bacteria, viruses, fungi, and other microbes, that live on and inside the human body, primarily in the gut. These microscopic inhabitants play a crucial role in digestion, and immunity, and can influence mood and mental health. The diversity and balance of the microbiome are essential for overall health, with research linking a healthy gut microbiome to a reduced risk of chronic diseases such as obesity, diabetes, and heart disease. Diet, lifestyle, and probiotics are key factors that can influence the health and diversity of the microbiome.
Micronutrient
Micronutrients are vitamins and minerals your body needs in small amounts. Unlike macronutrients (carbohydrates, proteins, and fats) that provide energy, micronutrients support a wide range of bodily functions like enzyme and hormone production, immune function, cardiometabolic health, and bone health. Deficiencies or imbalances in micronutrients can lead to health problems and disease. Eating a varied and balanced diet — fruits, vegetables, complex carbohydrates, healthy fats, and quality proteins from animal and plant sources — should cover all your micronutrient needs, if you’re a healthy individual. If you’re vegan/vegetarian, pregnant, or have a gastrointestinal disease, you may need to supplement at the advice of your doctor.
O
Obesity
Obesity is a condition characterized by excessive body fat accumulation that can negatively impact your health. According to the World Obesity Federation, over half (i.e., the majority) of the global population will be overweight or obese by 2035, and about 25%, or almost 2 billion people, will be obese. Obesity is often measured by the body mass index (BMI), a calculation based on height and weight, though other methods — like waist circumference, waist-to-hip ratio, skinfold thicknesses, and bioelectrical impedance — are used as well in clinical settings. Obesity increases the risk of numerous metabolic health issues, including insulin resistance, glucose dysregulation, high blood pressure, heart disease, and type 2 diabetes. Addressing obesity involves a holistic approach that includes dietary changes, increased physical activity, lifestyle adjustments (specifically in the areas of stress and sleep), and sometimes medical or surgical interventions, aimed at reducing body fat and improving overall health.
P
Polycystic ovarian syndrome (PCOS)
Polycystic ovarian syndrome (PCOS) is a common hormonal disorder among women of reproductive age, marked by a combination of symptoms like irregular menstrual cycles, excess androgen levels (leading to acne and unwanted body or facial hair), and polycystic ovaries. The exact cause is unknown, but insulin resistance, inflammation, and hormonal imbalances play key roles. Managing PCOS often involves lifestyle changes such as diet, exercise, and weight management, in addition to medication aimed at regulating hormones and improving symptoms.
Postprandial glucose levels
Postprandial glucose levels refer to the concentration of glucose in the blood after eating. These levels provide insight into how effectively your body manages sugar from meals. Before a meal (in a fasting state), your glucose levels should ideally be between 70 and 100 mg/dL (3.9 and 5.6 mmol/L). Two hours after eating, your levels should ideally be less than 140 mg/dL (7.8 mmol/L). Chronic elevated postprandial glucose levels can indicate a risk for developing cardiovascular disease and type 2 diabetes. Eating a metabolically friendly diet is key to avoiding large postprandial spikes.
Processed food (also ultra-processed food)
Processed food has been altered from its natural state for safety reasons or convenience, but not all processed foods are unhealthy. For example, almond butter, nut milk, and frozen broccoli are all processed to some degree. Ultra-processed foods, on the other hand, are significantly changed, typically with added ingredients like sugar, salt, fat, and artificial colors or preservatives. These foods are often high in calories and low in nutrients and fiber, contributing to unhealthy dietary patterns that can lead to glucose dysregulation, obesity, and chronic diseases. Choosing minimally processed whole foods as much as possible and avoiding added sugar is a simple way to jumpstart your metabolic health journey.
R
Resistance training
Resistance training, also known as strength training or weight lifting, is a form of physical activity designed to improve muscular fitness by exercising a muscle or a muscle group against external resistance. This resistance can come from dumbbells, weight machines, resistance bands, or even your own body weight. Regular resistance training not only builds and tones muscles but also boosts metabolism, supports bone health, enhances posture, and can reduce the risk of injury. Lean muscle mass from resistance training also burns more calories at rest and improves glucose absorption from the blood, making it a key part of metabolic health and body composition.
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Sauna
A sauna is a small room or house designed for experiencing dry or wet heat sessions, which can promote sweating and relaxation. Traditionally used for centuries in various cultures, notably in Finland, saunas are associated with improved circulation and cardiovascular health, reduced inflammation, enhanced cognitive function, and improved release of toxins through sweating. Research also suggests that saunas may increase levels of heat shock proteins that improve insulin sensitivity, regulate glucose levels, and reduce muscle protein breakdown.
Seed oil
Seed oils are extracted from the seeds of plants and are commonly used in cooking and food preparation due to their affordability and neutral flavor. Examples include sunflower oil, canola oil, flaxseed oil, and grape seed oil. Despite popular claims, there seems to be little evidence to back up the claims that seed oils are toxic, cause inflammation, or are rancid. On the contrary, seed oils can be a good source of unsaturated fats, including omega-3 and omega-6 fatty acids, which are essential for heart health and reducing inflammation. However, the nutritional value and health effects of seed oils can vary depending on their processing/refinement and the balance of fatty acids they contain, so it’s a good idea to opt for high-quality, cold-pressed oils when possible and avoiding fully hydrogenated (or solid) seed oils like margarine to protect your heart health.
Sleep
Sleep is an essential, often underappreciated, component of overall health and well-being. It is a restorative process that affects nearly every tissue in our body, including brain health, heart health, metabolism, immune function, and mood. Getting adequate sleep (typically 7-9 hours for most adults) and quality sleep (consistent sleep/wake times, optimal temperature, minimal light) also affect your metabolic health. Not getting enough sleep or poor-quality sleep can increase insulin resistance, leading to hyperglycemia, fatigue, weight gain, dysregulated appetite, and more. For sleep hacks, check out our blog.
Stress
Stress is your body’s natural reaction to difficult situations. In short bursts, stress can be positive, such as when it helps you avoid danger or meet a deadline, or during high-intensity exercise, sauna sessions, and intermittent fasting. However, chronic or prolonged stress can have serious health consequences. This is because cortisol (see above), the stress hormone, promotes insulin resistance. When your cortisol levels stay high for a sustained period of time, your body will also be less insulin-sensitive. Research also shows that stress modifies your behavior, leading to increased appetite and cravings for sweet foods. Techniques such as breathwork, meditation, exercise, and community are key to managing your stress levels.
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Testosterone
Testosterone is a key hormone in both men and women. It plays a crucial role in muscle mass, fat distribution, bone density, and the production of red blood cells and sperm. It’s also connected to metabolic health. Women with metabolic syndrome tend to have higher levels of testosterone and other androgens, which can disrupt the menstrual cycle. On the other hand, men with metabolic syndrome have lower levels of testosterone and may experience problems with erectile dysfunction, fatigue, reduced libido, infertility, and decreased muscle mass.
Time-restricted eating
See "intermittent fasting" entry above.
Type 3 diabetes
Type 3 diabetes is an informal term sometimes used to describe Alzheimer’s disease. It suggests that type 2 diabetes, insulin resistance, and insulin-like growth factor dysfunction are linked to the function of the brain’s neurons, contributing to Alzheimer’s. While not officially recognized in medical terminology, the concept highlights the potential connection between metabolic health and neurodegenerative diseases, emphasizing the importance of maintaining overall metabolic health to support brain health, particularly as you age.
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Ultra-processed food
See "processed food" entry above.
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Walking
Walking is one of the most accessible and straightforward forms of physical activity. As a low-impact, moderate-intensity exercise, walking can improve cardiovascular health, aid in weight management, enhance mood, and increase energy levels. It requires no special equipment and can be easily integrated into daily life, making it an excellent way to increase physical activity. Going on a 30-minute walk within 15 minutes of eating a carbohydrate-heavy meal can also help minimize a large glucose spike, as well as improve your other markers of metabolic health.
Weight loss (weight loss plateau, stages of weight loss)
Weight loss is a process where you aim to reduce body fat, improve health, or both. It often involves a combination of diet and exercise. While the typical timeline of weight loss varies from person to person, it generally involves three stages: (1) rapid weight loss, (2) slow weight loss, and (3) weight loss plateau. This last stage occurs when progress seems to halt despite continuing with a diet and exercise regime. This plateau is a natural response as your body adapts to lower energy intake and increased efficiency — i.e., the number of calories you need to survive lowers and becomes more or less equal to the calorie deficit you’ve been maintaining. There are also many other reasons — including insulin resistance, leptin resistance, stress, meal timing, and others — that may be keeping you from losing weight.
