Written and medically reviewed by Rich LaFountain, PhD
According to a recent study, only 6.8% of Americans are in good metabolic health — a worrisome statistic. But what does it really mean? And how can you not only assess your metabolic health, but actively improve it?
Metabolic Health Is More Than a Lack of Disease
Thus far, scientists and clinicians haven’t agreed upon a singular meaning for “metabolic health.” As a result, they generally define it as the absence of risk factors for cardiovascular disease and diabetes (collectively named “metabolic syndrome”).
The problem with this approach is that it keeps us focused on avoiding metabolic disease rather than achieving metabolic health. Success orientation is altogether different from failure avoidance, and we believe that nobody reaches their true potential through avoiding failure. Therefore, metabolic health is not adequately defined by absence or temporary avoidance of metabolic syndrome. It needs a unique definition and set of criteria that we can aim for.
Re-Defining Metabolic Health
While they may not have given us a singular definition of metabolic health, scientists and clinicians have given us a plethora of reliable data surrounding metabolic health metrics. Blood glucose, lipid profile, waist circumference, body composition, resting heart rate, and blood pressure are just a few of the many metrics that matter to your metabolic health.
After synthesizing the literature, we have identified five objective metabolic health criteria you can use to monitor and promote your metabolic health year after year.
#1. Keep Glucose Levels Steady
Your body’s cells rely heavily on glucose as a fuel source for energy production. Some cells, like red blood cells, rely almost exclusively on glucose. Therefore, the way that your body manages glucose is a major contributor to your overall metabolic health.
There are several blood tests that you can request to learn more about how your body manages glucose. Your fasting blood glucose (FBG) can be seen as a baseline, revealing how your body maintains glucose when you have not eaten for several hours. After an overnight fast, your fasting blood glucose levels should be 70–100 mg/dl.
Another test you can request is glycated hemoglobin (HbA1c), which reveals your average blood glucose across the past 6–8 weeks. As a general rule, the lower your HbA1c, the better your metabolic health is likely to be. The optimal HbA1c range is 4.0% – 5.5%.
Take Action: To maintain healthy blood glucose levels, focus on getting good sleep, exercising regularly, and avoiding processed high-carbohydrate foods.
#2. Measure More Than Just “Good” and “Bad” Cholesterol
Like carbohydrates, lipids (a.k.a. fats and oils) are a primary energy source for your body. They also contribute to cell structure, hormone levels, and temperature regulation. That said, too much of certain kinds of lipid particles can contribute to poor metabolic health. Some of these are tested as part of a basic lipid panel, but there are other tests you should consider requesting when you go for an annual checkup.
A standard lipid panel will provide you with high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). Each of these gives you information about how your body interacts with and transports fat around in your body. HDL-C facilitates transport of cholesterol from blood to the liver, where it can be put to good use rather than clogging up blood vessels. The higher your HDL-C the better, so shoot for >50mg/dL. Historically, LDL-C has been used as a key biomarker for cardiovascular disease risk. The optimal LDL-C is <100 mg/dL.
Triglycerides are packaged into lipoproteins like HDL-C or LDL-C in order to be transported in the blood. Keeping your blood triglyceride levels low reduces inflammation and neutralizes a major contributor to metabolic disease risk. Ideally, when you’ve fasted overnight, your TG in your blood is <100 mg/dl.
In addition to the normal lipid panel, two specific tests you should consider requesting are LDL particle size (LDL-P) and apolipoprotein B (ApoB). We now know it is specifically the small LDL particles that have the greatest potential to damage your blood vessels and lead to heart attacks. Therefore, you want to keep LDL-P below 1,000 nmol/L. Meanwhile, ApoB is a specific marker that allows you to measure the total unhealthy lipoproteins (VLDL, IDL, LDL and Lp[a]) circulating in your blood. Ideally your ApoB concentration should be as low as 60–65 mg/dl for improved disease protection and longevity.
Take Action: To achieve a healthy lipid profile, exercise consistently, regularly consume marine-based omega-3 fatty acids, and emphasize fiber in your diet.
#3. Improve Your Body Composition
Body size, weight, and body composition have been linked to metabolic health for over 200 years. Therefore, there are many options available for taking these measurements and making sense of them. BMI is the most popular body weight metric, but validated indices that incorporate height, weight, and waist circumference like Relative Fat Mass (RFM) and Optimal Anthropometric Index (OAI) may give a more accurate assessment of metabolic health status.
National Health and Nutrition Examination Survey data demonstrates that maintaining waist circumference within a specific range based upon your biological sex (27.5–35 inches for women and 31.5–39 inches for men) protects against metabolic disease. Similarly, maintaining a healthy body composition — i.e., the ratio of lean muscle to fat — promotes metabolic health and longevity. The optimal body fat percentage to support metabolic health is 20–30% for women and 12–20% for men.
Take Action: To improve your body composition and reduce fat, especially around your waist, exercise and nutrition provide a one-two punch. Any increase in physical activity — including chores or leisurely walking, but especially resistance exercise — will help maintain a healthy body weight and improve body composition, as will prioritizing daily protein intake and eating a healthful diet of high-quality, minimally processed foods.
#4. Lower Heart Rate and Blood Pressure
A low resting heart rate (RHR) is one of the best indicators of overall healthy metabolic function and lifestyle. Research suggests that reducing your resting heart rate from 70 to 60 beats per minute can extend your life by 10 years or more. (A metabolically healthy RHR is <64 beats per minute.) The good news is that you can easily monitor this metric thanks to smartwatches and other tools that keep track of cardiopulmonary function.
A slightly less convenient-to-measure indicator of metabolic health is low blood pressure. Keeping your resting blood pressure lower than 120/80 mm of Hg (provided you do not experience feeling light-headed or dizzy) helps to prevent disease, even if you are otherwise healthy or at low risk.
Take Action: To keep your resting heart rate low, focus on maintaining high aerobic fitness, sustaining a healthy body weight, and hydrating adequately. A healthy diet and virtually any exercise are also highly beneficial.
#5. Strengthen Your Mitochondria AND Your Muscles
One of the best things you can do to support metabolic health is to train your body and your mitochondria to efficiently use oxygen and produce fuel for exercise (a.k.a. improve cardiorespiratory fitness). You do this by . . . exercising!
The primary metric associated with cardiorespiratory fitness is VO2max, which can be measured using lab equipment or estimated using several validated methods, one of which involves only a known distance and a stopwatch. Optimal metabolic health and longevity are associated with a VO2max at or above the 75th percentile for your demographic group.
Healthy functional (i.e., skeletal) muscle is another incredible asset for assessing, improving, and preserving metabolic health. To assess your functional muscle, you can estimate your maximal strength with common gym movements such as squat and bench press. (Be careful to ensure safe practices if you test with weight-lifting equipment.)
Take Action: To improve your VO2max, research suggests a mixture of moderate and vigorous exercise at least three days. (In three months, you could see a 30% improvement!) To build and maintain healthy functional muscle, strength train 2–3 times a week.
While all of these metrics are important, remember: Metabolic health is not binary, it’s a continuum. You should strive to maintain as many healthy metrics as you can, but don’t panic if you’re not meeting the intended target on each metric, or if some of the numbers shift over time. The goal is progress over perfection.
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