The Ancient 'Omen' Hiding in Your Belly
Ancient Egyptian priests wanted to know what future waited for their dead...
And to do that, they needed a look at the deceased's belly fat.
During the mummification process, priests and embalmers would carefully pull back the skin to examine the apron-like layer of fatty tissue that hung over the intestines of the deceased. Namely, the priests believed the tissue carried a prophetic meaning. (And the fortune reading often depended on how much the deceased's family was willing to cough up.)
Today, we call this layer of fatty tissue the "omentum." The name is derived directly from this ancient practice of reading omens.
The omentum happens to be a major source of visceral fat. And it turns out, the amount of fat hidden deep inside your belly can lay out a course for your future health...
Not All Fat Is Created Equal
First, let's talk about fat...
If you look at a generic body mass index ("BMI") chart in a doctor's office, it gives you a single (though oversimplified) answer about your weight: a label categorizing you as underweight, normal, overweight, or obese. But your overall weight doesn't tell the whole story. That's because your body contains two main types of fat that behave differently.
The first type is called subcutaneous fat. It's the kind that sits right below your skin. You can physically pinch it on your arms, hips, thighs, and buttocks.
While no one loves carrying extra pounds – and the diet industry makes billions trying to get us to lose it – compared with visceral fat, subcutaneous fat is generally less harmful metabolically, especially in moderate amounts.
It makes up roughly 80% of total body fat in a healthy person. It also has an important purpose – specifically, protecting us. It does things like:
- Cushion our bones from falls
- Provide a reserve of energy
- Regulate body temperature
The second kind of fat is visceral fat. And this is the killer hiding below your belt...
This fat is your omentum, and it's located deep in your abdominal cavity. You can't always touch it or see it. You can even appear relatively thin on the outside but still hide dangerous levels of visceral fat on the inside, wrapped around vital organs like your liver, intestines, and pancreas.
Surgeons in the early 20th century called the omentum the "abdominal policeman." That's because it has the unique ability to migrate toward internal infections to protect the organs by wrapping itself around inflamed areas to seal off the infection while pumping out immune cells. But when we overfeed our bodies and lead sedentary lives, this protective layer expands and starts turning against us.
Visceral fat is known to trigger inflammation and cause insulin resistance. That's why excess visceral fat has been linked to cardiovascular problems like high blood pressure, high cholesterol, and heart disease, as well as metabolic problems like Type 2 diabetes, and fatty liver disease.
The Brain Connection
Now, we've known for a while that a thick waistline threatens your heart. But we're now discovering the connection between visceral fat and brain health.
Take, for instance, a new study published in March in the journal Nature Communications...
Researchers followed 533 adults aged 61 years on average for up to 16 years. Instead of looking at just general weight or standard waist measurements, they used advanced MRI scans to look deep inside the participants' bodies. By doing so, they could track the exact volumes of visceral fat and brain tissue over a long period of time.
Researchers found that participants who had higher levels of visceral belly fat experienced significantly faster brain atrophy, or shrinkage. And they also scored lower on cognitive tests.
Their brain ventricles, or the fluid-filled spaces in the brain that expand as the surrounding tissue dies off – grew at a highly accelerated rate.
According to the research team, impaired blood-sugar control appeared to be one of the main culprits. Insulin resistance from visceral fat leads to chronically high blood-glucose levels. Over time, this imbalance and constant barrage of inflammatory cytokines (or chemical signaling molecules used by the immune system) damage the delicate blood vessels in your brain that keep the tissue healthy.
But there is a bit of good news in this study...
The participants who successfully lost – and kept off – their visceral fat preserved their brain volume and maintained cognitive function years into the future. In other words, losing the belly fat put the brakes on brain aging.
What You Can Do Today
Your genetics has a hand in where your body tends to naturally store fat. That's not something you can control. But you do have control over the lifestyle and environmental factors that play a role in your visceral fat levels. Here's what you can do to protect your heart and your brain...
Measure your waist circumference. Instead of solely relying on the bathroom scale, get a tape measure and wrap it around your bare abdomen, just above your hip bones and below your ribcage. Keep the tape snug but don't pull it tight enough to compress the skin. Take the measurement when you exhale. For a simple rule of thumb, make sure that your waist circumference is less than half of your height. For instance, if you're 5'9" (69 inches) and your waist measures more than 35 inches, it's time to start taking action.
"Spot reduction" is a myth. You can't do just situps or crunches to banish deep organ fat. To burn this off, you need to start with consistent, moderate-intensity aerobic exercise. Try taking a brisk 30- to 45-minute walk five days a week to start oxidizing and burning off extra visceral fat for energy.
Try my favorite diet. Eating lots of ultra-processed foods is linked to having more visceral fat. So switch to my favorite way of eating: the Mediterranean way. It's rich in healthy fats and fiber from foods like fatty fish, leafy greens, legumes, nuts, and whole grains. Do what I do and replace butter and other oils with extra-virgin olive oil.
And get this: A November 2025 JAMA Network Open study followed 7,256 U.K. adults aged 49 on average for roughly seven years. Researchers found that the participants who more closely followed a Mediterranean-style diet or increased their physical activity gained less visceral fat and total body fat over time, compared with people whose habits didn't improve. What's more, the best results were seen in people who improved both habits.
Manage your stress and sleep. Being chronically stressed means your body is constantly pumping out cortisol, the "fight or flight" hormone that tells your body to hoard visceral fat in your belly. Those high cortisol levels also suppress production of the sleep hormone melatonin. And disrupted melatonin production and poor sleep can also contribute to visceral-fat accumulation.
What We're Reading...
- Did you miss it? The truth about your BMI.
- Something different: Happy Mother's Day to these nine bold, beautiful, and bizarre moms.
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
May 12, 2026