Fewer Than 1 in 15 American Adults Are Metabolically Healthy

Most people judge their health by how they feel and what the scale says. Metabolic health is harder to see. It lives in blood vessels, the liver and the pancreas, and it can deteriorate for a decade or more before it produces a symptom. By the time someone is diagnosed with type 2 diabetes or has a first heart attack, the underlying process has usually been running for years.

A 2022 study from researchers at Tufts University put a number on how widespread the problem is, and the number is small in the worst way.

The 6.8 percent finding

The team analyzed data from more than 55,000 adults in the National Health and Nutrition Examination Survey between 1999 and 2018. They defined optimal cardiometabolic health using five components, which were body fat measured by body mass index and waist size, blood sugar, blood lipids, blood pressure, and the absence of clinical cardiovascular disease.

As published in the Journal of the American College of Cardiology¹, only 6.8 percent of US adults met the optimal mark on all five in 2017 to 2018. That was down from 1999 to 2000. The biggest slides were in body fat and blood sugar. The share of adults with optimal glucose levels fell from about 59 percent to about 37 percent. Blood lipids actually improved over the period, a likely reflection of wider statin use.

The disparities were stark. Optimal cardiometabolic health was rarer among men than women, rarer among older adults than younger ones, and rarer among people with less education.

The share of adults with optimal blood sugar fell from about 59 percent to about 37 percent in two decades.

The study used a strict definition. Plenty of people outside the 6.8 percent are not in danger. But the finding is a useful corrective to the assumption that feeling fine means being fine.

Five numbers worth knowing

The good news is that the core markers are inexpensive to measure. A widely used framework for metabolic syndrome², agreed on by several international health organizations in 2009, uses five criteria. Having three or more signals elevated risk.

The first is waist circumference. For many US adults, the commonly cited thresholds are 40 inches for men and 35 inches for women, measured at the top of the hip bone. Fat stored around the organs is more metabolically active and more dangerous than fat stored elsewhere, and the tape measure catches what body mass index can miss.

The second is triglycerides, with 150 milligrams per deciliter or higher counting as elevated. The third is HDL cholesterol, with less than 40 in men or less than 50 in women counting as low.

The fourth is blood pressure. The metabolic syndrome criteria flag 130 over 85 or higher, while the 2017 American College of Cardiology and American Heart Association guideline³ defines stage 1 hypertension as starting at 130 over 80. Home readings taken over several days are often more accurate than a single office measurement.

The fifth is fasting glucose of 100 milligrams per deciliter or higher. Many clinicians also check hemoglobin A1C, which reflects average blood sugar over roughly three months. An A1C of 5.7 to 6.4 percent is in the prediabetes range. According to the Centers for Disease Control and Prevention⁴, a large share of American adults have prediabetes, and most of them do not know it.

Why it is worth catching early

Metabolic dysfunction is not a single disease. It raises the odds of heart disease, stroke, type 2 diabetes, fatty liver disease, kidney disease and some cancers. The upside is that the earlier it is caught, the more responsive it tends to be.

The interventions with the most evidence are familiar for a reason. Regular physical activity improves insulin sensitivity within days and cardiorespiratory fitness over months. A diet built around minimally processed foods and plenty of fiber improves glucose and lipids. Losing even 5 to 10 percent of body weight can meaningfully improve blood pressure, triglycerides and blood sugar. Sleep matters too, because short sleep worsens insulin resistance.

For people who need more help, medications including statins, blood pressure drugs, metformin and GLP-1 receptor agonists can change the trajectory substantially.

Start with a baseline

If you have not had these numbers checked in the last year, that is the first step. Ask for a lipid panel, fasting glucose or A1C, a blood pressure reading and a waist measurement at your next visit. Some clinicians add markers such as fasting insulin, liver enzymes or lipoprotein(a) to round out the picture.

The point is not to chase perfect numbers. It is to know which direction you are heading while there is still plenty of time to change course.