Metabolic Health: Why You Must Care and How to Measure It

Are you metabolically healthy? If not, you’re not alone. Only around 12% of Americans have achieved metabolic health.¹ What does metabolic health mean and why do we all need to start caring more about it? How do you measure metabolic health?

Let’s start by looking at the word metabolism. A lot of people misconceive the word metabolism and think it’s related to their weight, or maybe how much belly fat they have, or how much fat mass they have.

However, the truth is the concept of metabolism is so much deeper and broader. Metabolism is the aggregate of all of the biochemical processes that are occurring in the body that includes the metabolic hormones, things like insulin, cortisol, leptin, testosterone, and growth hormone. These hormones really drive so many factors when it comes to metabolic health and it determines how you feel today, and equally important, how you’re going to age over the next few decades, including your risk of chronic diseases such as pre-diabetes, diabetes, heart disease, stroke and even cancer.

How to Measure Metabolic Health

A weight that is in the normal range on the Body Mass Index (BMI) doesn’t necessarily correlate with optimal metabolic health because BMI doesn’t factor in body fat composition or muscle mass. While being overweight or obese is often a factor when assessing metabolic health, we need to look under the hood, so to speak, and perform several tests. 

Below are some of the basic tests to determine how to measure your metabolic health. I commonly use continuous glucose monitoring to make a lot of this comprehensive testing easier.

Fasting Glucose

This tells us how the body performs vis-à-vis insulin and glucose pathways in the absence of food.
Target levels: 70 to 85 mg/dL, or even 65-85 mg/dL in my patients in ketosis

Post-prandial Glucose (within 2 hours)

There are many roads to metabolic dysfunction. Not all prediabetics have high fasting glucose, so we want to look at the full dynamic range.
Target levels: The mainstream range cut off is < 140 mg/dL at 2 hours. I like 115 mg/dL.

Hemoglobin A1C

This test shows the three-month average of your glucose levels. The downside of this test is that it is not a linear reflection. Therefore, it can be falsely low for people who have hypoglycemia at night, something I see in a lot of perimenopausal and menopausal women.
Target levels: the American Diabetes Association (ADA) would say <5.6% but I like <5.2%. In some prediabetics, I’m aiming for <5%, but there are limitations to the test so we need to look at the total picture.

Insulin

Insulin can change years before glucose levels indicate diabetes.² Generally, post-prandial insulin changes first when metabolism starts to get out of balance. In many of my patients, I use a 2-hour glucose challenge test, where we check insulin and glucose at fasting, 30 minutes, 60 minutes, 90 minutes following a 75-gram load.
Target levels: Fasting insulin uIU/mL 4–6
After a 75-gram load, I like insulin to be <40 at 30 minutes, <30 at 60 minutes, and <20 at 90 minutes.

HOMA-IR (Homeostatic Model Assessment for Insulin Resistance)

Target Levels: <1 indicates insulin sensitive state

Thyroid Panel

Most doctors only check TSH and sometimes free T4, when they run a thyroid test. However, it’s important to add free T3, reverse T3, and thyroid antibodies (thyroid peroxidase antibodies and anti-thyroglobulin antibodies).
Target levels:
TSH (serum)mIU/L 0.3-2.5
Free T3 (serum) pg/mL 2.8-4.4
Free T4 (serum) ng/dL 0.9-1.7
Thyroid peroxidase TPO (serum) IU/mL < 9 (depends on lab)
Anti-thyroglobulin (serum) IU/mL < 4 (depends on lab)

Advanced Lipid Panel

This is not the old school version of total cholesterol, LDL, HDL, and triglycerides, but lipoprotein fractionation NMR with lipids (includes LDL-P, small LDL-P, LDL size, HDL-P, large HDL-P, HDL size, large VLDL-P, VLDL size), lipo(a), hsCRP, myeloperoxidase, oxidized LDL, HDL function, etc.

However, most doctors don’t order such an advanced panel for their patients. So while I may disregard the mainstream guidelines for some biomarker measurements, such as LDL, I share a few of my optimal ranges here:

• HDL cholesterol
  We are in transition with HDL and realizing the number matters less than the function, so I check HDL function in my patients with Cleveland Heart Lab (available at Quest)
  I target HDL function not an absolute number but low HDL is still a criteria of metabolic syndrome. For more details on why this is an important biomarker to measure, read an article I co-authored with Dr. Mark Houston.³
• LDL cholesterol
  I measure ApoB and NMR Lipoprotein fractionation which I consider more important and a deeper view of lipoprotein metabolism.
  Target levels: I want ApoB < 70 mg/dL in most of my patients but each person needs to be risk stratified.
• Triglycerides
  These reflects a type of fat in the blood and may reflect caloric excess
  Target levels: <150 mg/dL, and I aim lower in my patients in whom we’re optimizing metabolic health, i.e., <100 or even <50

hsCRP 

This is a clinical biomarker of general and cardiac-related inflammation.
Target levels: <1 is common in precision medicine, I aim for <0.5 mg/L in most of my healthy patients who are not elite athletes

As I cover in my new book, WOMEN, FOOD, AND HORMONES, these are the basic tests of your metabolic health. Additionally, I will also test hormones, like free and total testosterone. There are dozens of hormones that affect metabolism, from cortisol to leptin to ghrelin to growth hormone to adiponectin, but the above tests are a good place to start for you to assess your metabolic health.

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1. J. Araújo, et al., “Prevalence of Optimal Metabolic Health in American Adults: National Health and Nutrition Examination Survey 2009–2016,” Metabolic Syndrome and Related Disorders 17, no. 1 (2019): 46–52.
2. A.G. Tabák, et al., “Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study.” Lancet 373, no. 9682 (2009):2215-21.
3. M. Houston, S. Gottfried, “Beyond HDL: New Insights into HDL Cholesterol Function in Cardiovascular Disease” Metagenics Institute, 2020. https://www.metagenicsinstitute.com/blogs/hdl-cholesterol-function/ accessed November 7, 2021.