Triglycerides Explained:
The Plain-English Range Guide

What they are

Triglycerides are fat in transit

A triglyceride is the form in which the body stores and transports most of its fat. The molecule is made of one glycerol backbone with three fatty acids attached, hence the name. When you eat fat, most of it is packaged into triglycerides inside intestinal cells and shipped through the bloodstream as chylomicrons to be either burned for energy or stored. When you eat more carbohydrate than the body needs in the moment, the liver converts the excess into triglycerides through a process called de novo lipogenesis and exports them into circulation packaged in very-low-density lipoprotein, or VLDL.^[1]

This is the first thing that surprises most people about triglycerides. The number on a lipid panel reflects fat in transit through the blood, but a large fraction of that fat was assembled by the liver out of carbohydrate, not eaten as fat in the first place. Fructose is the clearest example, because it is metabolized almost entirely in the liver and is a particularly potent driver of de novo lipogenesis. In a controlled ten-week study, overweight adults who drank fructose-sweetened beverages supplying a quarter of their energy increased de novo lipogenesis, developed dyslipidemia, and lost insulin sensitivity, while those drinking glucose-sweetened beverages did not, even though both groups gained similar weight.^[4] This is why a diet high in refined carbohydrate and added sugar reliably elevates fasting triglycerides even in the absence of meaningful fat consumption, and why the low-fat era, which replaced fat with refined starch and sugar, so often produced rising triglycerides rather than falling ones.

The numbers, in plain English

What the normal range actually says

A standard fasting lipid panel categorizes triglycerides into roughly these bands (units are mg/dL, as used in the United States):

• Normal: below 150 mg/dL
• Borderline high: 150 to 199 mg/dL
• High: 200 to 499 mg/dL
• Very high: 500 mg/dL and above

Outside the United States, the same panel is usually reported in mmol/L. The conversion factor is 0.0113. So 150 mg/dL is approximately 1.7 mmol/L. The bands are otherwise identical.

There is an important nuance the "normal" label hides. A triglyceride number under 150 mg/dL is the official cutoff for "normal," but the metabolic literature has converged on a much more demanding optimal range. A fasting triglyceride below 100 mg/dL (about 1.1 mmol/L) is the genuine optimum.^[1] Numbers between 100 and 150 are technically normal but increasingly recognized as a sign of early insulin resistance: in overweight adults, a fasting triglyceride at or above roughly 130 mg/dL is one of the single most useful lipid-panel markers for identifying insulin resistance.^[5] Numbers between 75 and 100 are characteristic of metabolically healthy populations. Numbers below 75 are common in plant-based eaters, in regular fasters, and in trained endurance athletes.

This matters because a person told their triglycerides are "normal" at 140 mg/dL may be reassured at the moment they should be informed. The lab range is a population threshold for clinical concern, not a target for health.

Why this number is so informative

Triglycerides as a metabolic mirror

Of all the lines on a standard lipid panel, fasting triglycerides are the most responsive to short-term metabolic changes and the most informative about insulin sensitivity. Total cholesterol moves slowly and is heavily influenced by genetics. LDL cholesterol is informative but takes months to shift meaningfully. HDL is slow to respond. Triglycerides, by contrast, can change measurably within weeks of an eating-pattern shift, and they track how well the body is handling carbohydrate, fat storage, and overall metabolic load.

The ratio of triglycerides to HDL cholesterol is particularly useful as a proxy for insulin resistance. In overweight adults, a triglyceride-to-HDL-cholesterol ratio at or above 3.0 (using mg/dL) identifies insulin resistance about as well as the full set of metabolic-syndrome criteria, while a low ratio is a strong sign of preserved metabolic flexibility.^[5] The ratio is calculable from any standard lipid panel and is one of the most overlooked metabolic signals in routine bloodwork.

This is also why a triglyceride number is rarely abnormal on its own. The Health Protocol reads it inside a cluster: the NHLBI and the American Heart Association both note that abdominal obesity, elevated triglycerides, lower HDL cholesterol, raised blood pressure, and higher fasting glucose tend to travel together as metabolic syndrome, a pattern now estimated to affect roughly a quarter of adults worldwide.^[2] The point, in the book's framing, is not to moralize body size but to recognize that central fat accumulation often signals a terrain in which insulin demand, inflammatory signaling, and cardiometabolic risk are moving in the wrong direction together. A rising triglyceride is one of the earliest readable lines in that shared drift.

What raises them, in order of impact

The inputs that move the number up

Triglycerides rise reliably in response to:

• Refined carbohydrate and added sugar, particularly fructose, which is processed almost entirely by the liver and drives de novo lipogenesis directly.^[4]
• Alcohol, which the liver prioritizes for processing and which suppresses fat oxidation. Even modest regular alcohol use produces measurable triglyceride elevation in most people.
• Recent eating. A triglyceride number drawn within hours of a fat-containing meal can be temporarily elevated by 50 to 100 percent, which is why standard lipid panels are drawn fasting (10 to 12 hours). Nonfasting values are not merely noise, however: in large population cohorts, elevated nonfasting triglycerides independently predict heart attack, ischemic heart disease, and death, which is part of why nonfasting panels are increasingly accepted in practice.^[6]
• Insulin resistance and visceral adiposity, which together raise the rate at which the liver releases triglycerides into circulation.
• Sedentary behavior, which reduces skeletal muscle's uptake and oxidation of circulating fat.
• Untreated hypothyroidism, certain medications (beta blockers, thiazide diuretics, oral estrogens, some antiretrovirals), and pregnancy.

What lowers them, in order of impact

The inputs that move the number down

Triglycerides fall reliably in response to:

• Reducing refined carbohydrate and added sugar. This is the single highest-leverage dietary change for elevated triglycerides. Many people see 30 to 50 percent drops within weeks of this change alone.
• Plant-based eating patterns, which combine low refined-carbohydrate density with high fiber that slows fat absorption and improves insulin sensitivity. Randomized trials find vegetarian and vegan patterns lower total and LDL cholesterol and apolipoprotein B, and improve markers of insulin sensitivity.^[T2][10]
• Time-restricted eating, which extends the daily fasting window during which the liver clears circulating fat. A twelve-week trial of ten-hour time-restricted eating in people with metabolic syndrome reduced weight, blood pressure, and atherogenic lipids.^[3]
• Daily moderate movement, especially after meals, which improves muscle uptake of triglycerides for oxidation.
• Reducing or eliminating alcohol. Often produces a 20 to 40 percent triglyceride drop in heavy drinkers within weeks of cessation.
• Omega-3 intake, particularly EPA and DHA from fatty fish or algal oil, which has a direct lowering effect at higher doses. A 2019 American Heart Association science advisory concluded that 4 grams per day of prescription omega-3 lowers triglycerides by roughly 20 to 30 percent, and by more than 30 percent in severe cases, without raising LDL cholesterol.^[9]
• Treating underlying insulin resistance or thyroid dysfunction when present.

When triglycerides are very high

The clinical concern threshold

Between the optimal range and the very high range sits the question most people actually face: does a moderately elevated triglyceride matter for the heart? The American Heart Association's scientific statement on triglycerides and cardiovascular disease treats fasting triglycerides as an independent marker of cardiovascular risk and sets the optimal level below 100 mg/dL.^[1] Pooled across twenty-nine Western prospective studies covering more than ten thousand coronary events, higher triglycerides were independently associated with coronary heart disease after adjustment for other risk factors.^[7] Genetic and Mendelian-randomization studies have since moved the case from association toward causation: the triglyceride-rich remnant lipoproteins the liver exports appear to contribute directly to atherosclerotic cardiovascular disease rather than merely mark it.^[8] This is the larger reason a triglyceride is worth reading carefully well before it reaches any clinical threshold.

Triglycerides above 500 mg/dL are a separate clinical category. At this level the risk of acute pancreatitis rises significantly, and aggressive intervention is warranted. People in this range should be working with a clinician. The first-line interventions remain dietary (sharp reduction of refined carbohydrate, alcohol elimination, weight loss) but may be supplemented with pharmacological options, including high-dose prescription omega-3, fibrates, and niacin in selected cases, depending on the clinical picture.^[9]

For the much more common situation of triglycerides between 150 and 300 mg/dL, the framework is the same one developed throughout The Health Protocol. The number is a signal, not a disease. It is responding to the inputs the body is receiving. Change the inputs and the number changes, and the cardiovascular risk it reflects tends to change with it, especially under the kind of whole-food, plant-forward pattern with the strongest convergent evidence for coronary protection.^[T1]

Where this lives in The Health Protocol

Mapped to the book

Triglycerides are part of the larger biomarker conversation in Chapters V and VI of The Health Protocol, which cover metabolic health and the cardiovascular consequences of metabolic dysfunction. The dietary patterns that move triglycerides are developed throughout Module 2 (Nourishment by Design) and the metabolic logic is the spine of Module 3 of the seminar (Metabolic Coherence).

The point is not to moralize body size. It is to recognize that central fat accumulation often signals a terrain in which insulin demand, inflammatory signaling, and cardiometabolic risk are moving in the wrong direction together.

The Health Protocol · Chapter V · p. 96