I have patients who weigh 200 pounds and are metabolically healthier than patients who weigh 150. I have patients with "obese" BMIs who run marathons and have perfect lipid panels. And I have patients with "normal" BMIs who are pre-diabetic, hypertensive, and inflamed.
Weight is not health. BMI is not health. Here's what actually determines metabolic health — and why we need to stop conflating the two.
The Five Pillars of Metabolic Health
In my practice, I evaluate five domains:
- Glycemic control: Fasting glucose, HbA1c, insulin levels. This is the foundation. Elevated insulin is the first sign of metabolic dysfunction, often years before diabetes.
- Lipid profile: Not just total cholesterol. LDL particle number, HDL function, triglycerides, and the triglyceride/HDL ratio. A TG/HDL ratio >3 is strongly predictive of insulin resistance.
- Blood pressure: Hypertension is often the first clinically obvious sign of metabolic syndrome. But it's usually the last domino to fall.
- Inflammatory markers: CRP, ferritin, uric acid. Chronic low-grade inflammation drives atherosclerosis, fatty liver, and neurodegeneration.
- Body composition: BMI, waist circumference, body fat percentage, muscle mass. Not just weight, but where weight is distributed and what tissues it's composed of.
A patient can be "overweight" by BMI but metabolically healthy if all five domains are optimal. Conversely, a "normal" BMI patient can be metabolically unhealthy if even one domain is compromised.
The Obesity Paradox
There's a phenomenon in cardiovascular research called the "obesity paradox" — overweight and mildly obese patients sometimes have better outcomes than normal-weight patients after cardiac events. The reasons are debated: maybe overweight patients have more metabolic reserve. Maybe they're diagnosed earlier because of more frequent medical contact. Maybe the normal-weight patients had undiagnosed sarcopenia.
I don't think it's a paradox. I think it's evidence that weight is a crude proxy for health. The real story is in the metabolic data.
What Patients Can Do
You don't need a $500 metabolic panel to assess your health. Start with what you can measure:
- Fasting glucose: Available at any pharmacy. Should be <100 mg/dL.
- Blood pressure: Home monitors are $30. Should be <120/80.
- Waist circumference: A tape measure costs $2. Should be <40" (men) or <35" (women), or <35"/31" for Asians.
- How you feel: Energy, sleep, mood, digestion. These are data too.
The calculators on this site are starting points. They screen for risk. But metabolic health is a multidimensional concept that no single number — not BMI, not weight, not body fat percentage — can capture.
— Dr. David Chen
Dr. Chen is a board-certified Internal Medicine physician. This article reflects clinical observations and personal experience. For medical advice, consult your healthcare provider.