Metabolic Health: The Five Markers That Actually Matter

A landmark study published in Metabolic Syndrome and Related Disorders in 2019 found that only 12.2% of American adults met all five criteria for optimal metabolic health — without the use of medication. This is a striking figure, and it reflects a broader pattern seen across high-income countries: metabolic dysfunction is common, often silent, and frequently underestimated because it does not always manifest as obvious illness.

Understanding metabolic health requires moving beyond the single metric of body weight. The five markers that clinicians and researchers use to define metabolic health collectively capture how well the body manages energy, regulates blood sugar, and maintains cardiovascular function.

The Five Key Markers

Why Fasting Blood Glucose Matters Most

Fasting blood glucose is arguably the single most informative metabolic marker for most adults. It reflects the body's baseline insulin sensitivity — the ability of cells to respond to insulin and absorb glucose from the bloodstream. Chronically elevated fasting glucose, even within the 'normal' range of 5.0–5.5 mmol/L, is associated with progressive insulin resistance and increased risk of metabolic dysfunction over time.

The trajectory matters as much as the absolute value. A fasting glucose of 5.4 mmol/L that has risen from 4.8 mmol/L over three years is more clinically significant than a stable reading of 5.5 mmol/L. This is why annual monitoring is more informative than a single data point.

Visceral Fat: The Hidden Driver

Waist circumference is a proxy for visceral adiposity — fat stored around the abdominal organs rather than subcutaneously. Visceral fat is metabolically active in a way that subcutaneous fat is not: it secretes pro-inflammatory cytokines, impairs insulin signalling, and contributes to dyslipidaemia. Two individuals with identical body weight can have dramatically different metabolic risk profiles depending on their fat distribution.

The Mitochondrial Connection

All five metabolic markers are influenced, to varying degrees, by mitochondrial function. Insulin resistance, for example, is strongly associated with impaired mitochondrial oxidative capacity in skeletal muscle — the inability of mitochondria to efficiently metabolise fatty acids leads to the accumulation of lipid intermediates that interfere with insulin signalling. Similarly, elevated triglycerides often reflect impaired mitochondrial fatty acid oxidation in the liver.

This is why strategies that support mitochondrial function — exercise, particularly aerobic and resistance training, adequate sleep, and targeted nutritional support — tend to improve multiple metabolic markers simultaneously rather than acting on a single pathway.

Practical Steps

The most evidence-based interventions for improving metabolic health markers are not novel: consistent aerobic exercise (150+ minutes per week of moderate intensity), resistance training (2–3 sessions per week), a diet low in refined carbohydrates and ultra-processed foods, adequate sleep (7–9 hours), and stress management. These interventions work through multiple mechanisms simultaneously and have decades of clinical evidence behind them.

Supplements can play a supporting role within this framework, particularly for adults who are already engaging with the lifestyle foundations and want to add targeted metabolic support. However, no supplement replaces the foundational interventions — and any clinician or product that suggests otherwise should be treated with scepticism.