Yes, belly fat matters for your heart, and it matters more than the number on the scale suggests. Fat stored deep in the abdomen, around the liver and intestines, is called visceral fat. It is tied to heart disease more closely than body weight alone.
That is why two people with the same body mass index (BMI) can have very different heart risk. It is also why a normal weight does not always mean a low risk.
Key takeaways
- Visceral fat sits deep in the belly around the organs and is linked to heart disease separately from BMI.
- A tape measure around the waist picks up information that the scale and BMI miss.
- People at a normal weight with a large waist can carry more risk than heavier people whose fat sits elsewhere.
- Waist size is a clue and not a diagnosis: blood pressure, cholesterol and blood sugar show what the fat is doing.
What visceral fat is
The fat you can pinch under your skin is subcutaneous fat. Visceral fat lies deeper, packed around the organs inside your abdomen. You cannot see it or pinch it.
A related idea is ectopic fat. This is fat stored in places that are not built to hold it, such as the liver and the area around the heart.
A joint position statement from the International Atherosclerosis Society and an international working group on visceral obesity reviewed 30 years of studies. It concluded that visceral fat, measured accurately by CT or MRI, is an independent risk marker for cardiovascular and metabolic illness and death.1 It added that fat in the liver and around the heart might contribute to risk as well.
Why BMI misses it
BMI compares your weight with your height. It cannot tell muscle from fat, and it says nothing about where fat is stored.
An American Heart Association scientific statement describes abdominal obesity, measured by waist circumference, as a cardiovascular risk marker that is independent of BMI. The same statement says imaging studies support excess visceral fat as an independent indicator of poor cardiovascular outcomes.2
The INTERHEART study shows the gap clearly. It compared about 12,500 people who had a heart attack with about 14,600 who had not, across 52 countries. Waist-to-hip ratio showed a strong, graded link with heart attack, while the link with BMI was no longer significant once other risk factors were taken into account.3
| Measure | What it tells you | What it misses |
|---|---|---|
| BMI | Weight relative to height | Where fat is stored, and how much is muscle |
| Waist circumference | A practical estimate of abdominal fat | Cannot separate deep fat from fat under the skin |
| Waist-to-hip ratio | How fat is distributed between waist and hips | Same limit as waist size, and harder to measure consistently |
| CT or MRI | A direct measure of visceral fat | Not a routine test for this purpose |
Normal weight, higher risk
You do not need to be overweight to carry too much visceral fat. Researchers call this pattern normal-weight central obesity.
A study of 15,184 US adults from a national health survey looked at what it means. People with a normal BMI but central obesity, defined by waist-to-hip ratio, had the worst long-term survival of any group. A man with a normal BMI and central obesity had an 87% higher risk of death than a man with a similar BMI and no central obesity, and for women the figure was 48%.4
Direct imaging points the same way. In the Framingham Heart Study, 3,086 adults had their visceral fat measured by CT and were followed for about five years. More visceral fat was linked with more cardiovascular events, even after accounting for BMI and standard risk factors.5
Both studies are observational. They show that central fat and worse outcomes travel together. They cannot prove that one causes the other, and the Framingham analysis rested on a small number of events.
How belly fat is tied to the heart
Visceral fat rarely shows up alone. It tends to come with a cluster of changes that each raise heart risk:
- Higher blood pressure
- Higher triglycerides and lower HDL cholesterol
- Higher blood sugar and insulin resistance
- Fat in the liver, covered in our guide to fatty liver and heart risk
- Low-grade inflammation
The American Heart Association statement notes that obesity contributes directly to abnormal blood fats, type 2 diabetes, high blood pressure and sleep disorders. These are the routes by which a large waist most often turns into artery disease.
Measuring your waist
A consensus statement from two international expert groups argues that BMI alone is not enough to assess the risk that comes with excess body fat. It recommends that waist circumference be measured routinely, like a vital sign.6
The measurement is simple: a tape around the bare abdomen, taken at the same landmark each time, after a normal breath out. Your clinician can show you the method they use.
We have not listed a single cutoff here on purpose. The same expert groups say that waist thresholds still need refining by age, sex and ethnicity, so ask your clinician which cut point applies to you. The trend in your own measurement over time is often more useful than one reading.
Can it change?
Yes. The consensus statement describes evidence that clinically relevant reductions in waist circumference can be achieved with routine moderate-intensity exercise, dietary changes or both.6
It is worth being precise about what that buys. The American Heart Association statement says lifestyle change and weight loss improve metabolic syndrome, inflammation and blood vessel function. It also says that, as of 2021, clinical trials of medical weight loss had not shown a reduction in coronary artery disease rates.2 Our guide to weight loss and heart risk covers the newer evidence.
Your next step
If your waist has grown, or you carry weight around the middle, the sensible move is to find out what it is doing to your numbers. Our guide to triglycerides and heart risk explains one of the blood markers that most often shifts with abdominal fat.
You can also answer the three quick questions in the screener on the Cardio Res-Q program page. Excess weight and insulin resistance are both on the list of risk factors the program screens for.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Can you have too much visceral fat at a normal weight?
Yes. In a large US survey study, adults with a normal BMI and a high waist-to-hip ratio had worse long-term survival than adults who were overweight or obese by BMI alone. A normal weight is good news, but it does not rule out fat stored around the organs.
Is waist size a better measure than BMI?
They work best together. Expert groups describe waist circumference as adding independent information to BMI, not replacing it. BMI tells you about overall size, and waist size tells you more about where the fat is.
How can I find out how much visceral fat I have?
CT and MRI measure it directly, but they are not routine tests for this purpose. In everyday practice, waist measurement is the practical stand-in, read alongside blood pressure, blood fats and blood sugar. Experts have noted the need for simpler clinical tools to track visceral fat over time.
Related reading
This article is for general education and is not medical advice. Decisions about testing and medication should be made with your clinician. If you have chest pain or other symptoms of a heart attack, call 911.
