Glossary

Metabolic Health Glossary

What insulin resistance, HbA1c, ApoB, GLP-1 and the rest of the words on your lab report actually mean: clear definitions from Dr. Leonardo Vergara.

Half of a consultation goes on translation. Here, in plain language, are the words that turn up on a lab report, in a package insert, or in a headline about Ozempic. There are no reference ranges and no cut-off numbers: those belong to your lab and to the doctor reading them. This is general education, not medical advice and not a diagnosis.

The essentials

7 terms

The handful of words that show up in almost every conversation about metabolism.

Metabolism

The whole set of processes your body uses to turn what you eat into energy and into the materials it repairs itself with.

It is not one switch set to fast or slow: it is thousands of reactions that respond to what you eat, how you move, how you sleep and how much stress you carry. That is why it can be influenced, even though it cannot be commanded.

Metabolic health

Your body handling blood sugar, blood fats, blood pressure and inflammation well, without having to strain.

It is judged by several markers together rather than any one of them, and it is not read on a scale: there are lean people with poor metabolic health and heavier people with good metabolic health. It is the ground almost everything else is played on.

Insulin

The hormone the pancreas makes so that glucose in the blood can get into your cells.

It is also a storage signal: while it is high, the body stores rather than releases. It is not the villain of the story — you cannot live without it — but its pattern across the day says far more than one isolated value.

Insulin resistance

When cells respond less well to insulin, so the pancreas has to make more of it to get the same effect.

It usually settles in years before fasting glucose ever moves, which is exactly why it goes unnoticed. It is also among the most modifiable things there are: movement, sleep, protein, fibre and body weight all push it in the right direction.

Blood glucose

Also: blood sugar

The sugar travelling in your bloodstream that your cells use as immediate fuel.

It rises and falls all day; what matters is not one isolated spike but how high it goes, how long it takes to come back, and how often that happens. Food order, fibre, protein and a walk after eating all soften the curve.

Prediabetes

A stage where blood sugar sits higher than expected but does not yet meet the criteria for type 2 diabetes.

The word is frightening, and in a way it should be: it is a warning that still comes with time attached. It is also the stage where habit change pays off most — and the diagnosis is made by a professional with tests, never by a web page.

Metabolic syndrome

A cluster of findings that tend to travel together: waist, blood pressure, triglycerides, HDL and glucose.

It is not a single disease but a pattern, and that is exactly its value: it forces you to look at the whole picture instead of chasing one loose number. The exact criteria are applied by your doctor, because they vary by guideline and population.

In the lab report

8 terms

What those acronyms actually measure. The ranges belong to your lab, and the reading to your doctor.

HbA1c

Also: glycated haemoglobin, haemoglobin A1c

A rough average of your blood sugar over the last few months, not of this morning.

That is why it cannot be fixed with two careful days before the blood draw. It can be distorted by anaemia and other red-cell conditions, so it is read alongside the rest of the panel and your history, never on its own.

Fasting glucose

Blood sugar measured after several hours without eating, usually first thing in the morning.

It is the most common test and also the slowest to raise a flag: it can stay in range while insulin has already been working overtime for years. Useful, but better in company than alone.

HOMA-IR

An index calculated from fasting glucose and fasting insulin to estimate insulin resistance.

Its value is that it requires measuring insulin at all, which many routine check-ups skip. It is an estimate, not a diagnosis, and the cut-offs differ between labs and populations: ask your doctor before you ask a search engine.

Triglycerides

The form in which the body transports and stores fat; measured in the same panel as cholesterol.

They respond strongly to excess sugar, alcohol and calories, and also to what you ate the night before — which is why they are drawn fasting. Their ratio to HDL is one of the most cited hints about how insulin is doing.

HDL cholesterol

The cholesterol fraction involved in carrying cholesterol from the tissues back to the liver.

Calling it “the good one” oversimplifies: raising it with supplements has not shown the benefit that was hoped for, and what matters is the full panel. It remains, even so, a useful piece of the metabolic puzzle.

ApoB

Also: apolipoprotein B

A protein carried one copy per particle, so measuring it counts how many atherogenic particles are circulating.

A growing number of guidelines treat it as a more informative measure of cardiovascular risk than LDL cholesterol alone, especially in people with high triglycerides. It is not always ordered routinely — it is worth asking about.

hs-CRP

Also: high-sensitivity C-reactive protein

A marker of low-grade inflammation — the kind you do not feel but that accumulates.

It also rises with recent infections, injuries and other acute causes, so a single value says little: it is interpreted in context and, if needed, repeated. Sleep, movement and body composition all influence it.

Biomarkers

Measurable signals of how the body is working: blood tests, blood pressure, body composition, physical capacity.

Their usefulness is in the trend, not the snapshot: a value changes meaning depending on where it was coming from. More tests is not the same as better information; a few well-chosen ones repeated over time are worth more.

In the body

7 terms

Where all of this actually happens: liver, muscle, fat, hormones and the internal clock.

Visceral fat

The fat that surrounds the organs inside the abdomen, different from the fat you can pinch under the skin.

It is metabolically active: it releases substances that take part in inflammation and insulin resistance. It is also among the first to respond when food and movement change, even if the scale is slow to show it.

Fatty liver

Also: hepatic steatosis, metabolic dysfunction-associated steatotic liver disease (MASLD)

A build-up of fat inside the liver, often with no symptom to give it away.

It is usually found by accident on an ultrasound or in altered liver enzymes, and it frequently travels with insulin resistance. In many people it improves when the metabolic ground improves; the follow-up is directed by your doctor.

Muscle mass

The tissue that moves your body and is also the main destination for the glucose in circulation.

That is why losing muscle worsens sugar handling even as weight falls: storage capacity goes with it. Protecting it during any weight-loss process — with enough protein and strength training — is a priority, not an extra.

Sarcopenia

The progressive loss of muscle mass and strength that comes with age and inactivity.

It advances quietly for decades and is noticed late, when getting up from a chair becomes work. It is one of the few ageing processes where strength training shows benefit at any age.

Chronic inflammation

Also: low-grade inflammation

A low-intensity immune response that, instead of switching off once its job is done, stays on.

It does not hurt the way a wound does, and that is precisely the difficulty. Too little sleep, sitting all day, sustained stress and excess visceral fat feed it; the opposite tends to bring it down.

Cortisol

A hormone that helps you wake up, mobilise energy and respond to a threat.

The problem is not having it but being unable to bring it down: when the threat never ends, that daily rhythm blurs and drags sleep, appetite and blood sugar with it. Rest is not a reward — it is part of the treatment.

Circadian rhythm

The roughly twenty-four-hour internal clock that organises sleep, hormones and how you handle energy.

Light is its main synchroniser: natural light early, dimness at night. Eating very late and sleeping at shifting hours knock it out of phase — and glucose tolerance shifts with it.

GLP-1s and medication

5 terms

The vocabulary of the most-asked topic. None of it replaces the person who prescribes for you.

GLP-1

Also: glucagon-like peptide-1, GLP-1 receptor agonists

A hormone the gut releases when you eat, involved in fullness and in the insulin response; it also names a family of medicines that imitate it.

The medicines in this family are real tools, with indications, contraindications and medical follow-up. They are neither a shortcut nor a moral failure: they are treatment, and they work better on a base of food, strength and sleep.

Semaglutide

The active ingredient in several GLP-1 medicines; the brand name changes with the indication and the country.

Knowing the active ingredient prevents confusion: two boxes with different names can hold the same thing, and two people “on the same drug” can be on different indications. What is prescribed, at what dose and for how long is decided by the clinician who treats you.

Tirzepatide

Another active ingredient in the same territory, acting on two hormone pathways instead of one.

A different mechanism does not automatically mean “better for you”: side-effect profile, availability, coverage and your clinical history weigh just as much. This is a conversation with your doctor, not a comparison of headlines.

Gastric emptying

The speed at which the stomach passes its contents on to the intestine.

GLP-1s slow it down, and that is part of why they satisfy. It also explains why large portions, eating fast or a lot of fat at once sit worse on these medicines: that is not a failure, it is the mechanism doing its job.

Food noise

The constant thinking about food that takes up mental space even when there is no physical hunger.

It is not a shortage of willpower: it is signalling that will not switch off. Many people who start a GLP-1 describe its silence as the most striking change, ahead of anything on the scale.

Habits and longevity

10 terms

The daily levers, and the two words this work is built on.

Intermittent fasting

Organising food into a window of hours, rather than changing what is eaten.

For some people it simplifies life and cuts grazing; for others it drives hunger and a night-time binge. It is not compulsory, and it does not suit anyone with a history of disordered eating, anyone pregnant, or anyone on medication that lowers blood sugar without discussing it with their doctor first.

Glycemic index

A scale that ranks carbohydrate foods by how fast they raise glucose when eaten alone.

“When eaten alone” is the small print: almost nobody eats that way. Adding protein, fat or fibre to the same meal changes the response more than the food's own index does.

Fibre

The part of plant foods we do not digest, and which feeds the bacteria in the gut.

It slows sugar absorption, increases fullness and improves transit. It is also the nutrient most people fall short on, and it rises better with real food than with a supplement.

Protein

The nutrient the body builds and repairs tissue with, starting with muscle.

It is also the most satiating macronutrient, so putting it first on the plate tends to order the rest of the meal without counting anything. How much each person needs depends on age, weight, activity and kidney function: that is a clinical conversation.

Strength training

Work against resistance — weight, machine, band or your own body — that asks the muscle for more than usual.

It is not cosmetic: it is the most direct way to keep muscle, bone and independence as the years pass. Starting late is still worth it, and starting gently with good technique beats starting hard and stopping.

VO₂ max

The maximum amount of oxygen your body can use during effort: a measure of aerobic capacity.

It is one of the most studied fitness markers in relation to long-term health, and it responds to training at any age. Watches estimate it; a lab measures it.

Longevity

How many years are lived. It is half the question.

The other half is what condition those years are lived in. It is built with ordinary decisions sustained over time — sleep, movement, food, connection — far more than with extraordinary interventions.

Healthspan

The years lived with independence, energy and function — not merely with a pulse.

It is the half usually missing from the longevity conversation. Strength, balance, aerobic capacity and metabolic health hold it up the most, and every one of them can be trained.

Zero Sugar

Dr. Vergara's approach to eating: take added sugar out of the centre of the plate and put real food back there.

It leans on quality protein, healthy fats, hydration and vegetables: not a list of bans but a shift in the centre of gravity. It is also the base of the RESET 30 programme.

Amor Consciente

Conscious love for the one body and the one life you were given: caring for yourself as an act of love, not of punishment.

It is the movement this work is named after, and the frame everything else in this glossary is read through: lasting discipline is born of affection, not of shame. A body that is hated is rarely cared for very long.

No definition on this page can diagnose you or justify changing a medication on your own. If something you read here fits what is happening to you, that is a good reason to book an appointment — not to open another tab.

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