Every year, millions of people receive their routine blood work, scan down the results, and focus on a single number: their LDL cholesterol. If it is high, they worry. If it is normal, they feel reassured. And according to Dr. Robert Lustig — neuroendocrinologist, metabolic health researcher, and author of Metabolical — both of them may be drawing entirely the wrong conclusions from an entirely inadequate test.
The Problem With Your Standard LDL Test
The LDL number on your standard lipid panel is not actually measured. It is calculated — derived from the Friedewald equation: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5). Lustig argues this calculated number is, at best, a crude approximation — because it treats LDL as a single uniform substance. It is not.
Large Buoyant LDL vs. Small Dense LDL
Large, buoyant LDL particles (Pattern A) are big, light, and largely benign. They do not readily penetrate the arterial wall, resist oxidation, and are not strongly associated with cardiovascular disease. Small, dense LDL particles (Pattern B) are small enough to penetrate the arterial wall, oxidize easily, trigger inflammation, and are the particles most strongly associated with atherosclerosis. The standard test cannot distinguish between these two.
What creates small dense LDL? Not saturated fat. The primary driver is excess fructose and refined carbohydrates. Lustig’s most pointed argument: the villain in the cardiovascular story is sugar — not saturated fat.
The LDL Test Lustig Says Should Be Standard
NMR LipoProfile
The NMR LipoProfile uses magnetic resonance technology to directly measure the number and size of lipoprotein particles. It produces LDL-P (the actual number of LDL particles), LDL particle size (Pattern A vs. B), HDL-P, and VLDL particle analysis — a substantially more informative picture than any standard lipid panel.
Apolipoprotein B (ApoB)
ApoB is the structural protein that coats every LDL, VLDL, and IDL particle — exactly one per particle. Measuring ApoB gives the total number of atherogenic particles with direct accuracy. Multiple large studies have demonstrated that ApoB is a stronger predictor of cardiovascular events than LDL cholesterol. It is a single blood test, not expensive, and almost never ordered as part of routine care.
The Lab Tests That Actually Reflect Metabolic Health
Fasting Insulin
Lustig calls fasting insulin one of the single most important and most underordered tests in medicine. Fasting glucose can remain normal for years while insulin is quietly rising. Lustig considers a fasting insulin above 7–10 μIU/mL indicative of early insulin resistance — even when fasting glucose is completely normal.
HOMA-IR
HOMA-IR = (Fasting Insulin × Fasting Glucose) ÷ 405. A score above 2.0 suggests insulin resistance. Above 2.9 indicates significant metabolic dysfunction. Because it requires fasting insulin, HOMA-IR is almost never calculated in routine clinical practice — yet Lustig considers it one of the most informative single numbers in metabolic medicine.
Triglyceride-to-HDL Ratio
Already calculable from every standard lipid panel — yet most clinicians never compute it. A ratio of 3.0 or above (in US mg/dL units) strongly suggests insulin resistance and Pattern B LDL. A ratio below 2.0 suggests metabolic health. In Canadian units (mmol/L), a ratio above 1.3 is considered concerning.
Published for educational purposes by CI Mavericks. This article does not constitute medical advice. Please consult a qualified healthcare professional regarding your individual health needs.