What is an Omentum?

Tricia Christensen
Tricia Christensen

The omentum is probably not a word most are familiar with, until 2007 when Oprah Winfrey invited Dr. Mehmet Oz to discuss the nature of excess body fat. For her television viewers, Dr. Oz introduced the concept, even showing both a healthy and an overly fat omentum to people to showcase the biological importance of this organ.

Beer belly is a common term used to describe an especially large omentum.
Beer belly is a common term used to describe an especially large omentum.

The Oprah segment took a somewhat simplified yet medically correct approach to explaining the omentum. Actually, this fold of tissue is split into two segments called the greater and lesser omentum. The greater is a mass that sits in front of the stomach, and the lesser covers the liver. Both become easy repositories for fat storage. When the greater omentum is especially large, the abdomen may appear stiff and distended bringing to mind the term beer belly.

The risk of diabetes rises with a fatty omentum.
The risk of diabetes rises with a fatty omentum.

The omentum easily stores fat, since it is readily accessible to the body. When people lose weight, it shrinks, helping to reduce risks for a number of conditions. Dr. Oz contends that the great concern with a fatty omentum is that it starts inflammatory processes, which can lead to diabetes, high blood pressure, and hardening of the arteries. Essentially the bigger it is, the more you are at risk for a variety of difficult illnesses.

The omentum easily stores fat.
The omentum easily stores fat.

This fold of tissue also receives and stores hormones like cortisol, called a stress hormone. High stress can stimulate its growth. People who are under a great deal of stress may find that reducing the size of this organ is very difficult, and they are often advised not simply to diet, but also to reduce stress through a variety of therapies, relaxation techniques, and lifestyle changes. Stress and tummy fat are inexorably connected.

The greater omentum is a mass that sits in front of the stomach, and can become an easy repository for fat storage.
The greater omentum is a mass that sits in front of the stomach, and can become an easy repository for fat storage.

The healthy omentum may still not be a pretty sight, unless viewing human anatomy thrills you. It is slightly yellow, somewhat similar in appearance to an uneven omelet. It should be nearly transparent, and have a lacy look.

A large and unhealthy omentum can be three to four times or even more the size of the healthy organ. Fat cells extend the area to make it appear like a weighty, globular mass. Even a person who is not significantly overweight can have a significantly large omentum as Dr. Oz demonstrated on Oprah’s show. A memorable screen shot is that of Oprah holding up the healthy one while Dr. Oz holds up one from a deceased man who was only about 30 pounds (13.61 kg) overweight. The contrast is striking.

Dr. Oz further gives measurements for what a healthy omentum size should be. The easiest way to measure is to measure from completely around the body, crossing over the belly button in the front. For women, this measurement should not exceed 32 inches (0.82 m). A healthy measurement for men is 35 inches (0.89 m). If the omentum measures larger than these figures, weight loss can help reduce risk of disease and promote overall better health and longevity.

Researchers believe there is a strong correlation between stress and fat storage.
Researchers believe there is a strong correlation between stress and fat storage.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


I had ovarian cancer, stage 4. My uterus and ovaries were removed and there were cancer cells all over the omentum so it had to be removed. What happens to the fat when there is no omentum? I can't seem to get a straight forward answer anywhere.


@lamaestra: every medical student knows what the omentum is and its significance/role/function, so certainly every doctor knows. It's certainly not a made up word. They've been telling us for years that belly fat is more dangerous and prone to cause health complications than the fat that goes to your hips or buttocks or other areas. Even if you've never heard of the omentum you may have heard that belly fat = bad news.


I heard about the greater omentum (and saw pictures) in my high school Anatomy and Physiology class in 1978. I was very impressed by the teacher saying adamantly that it was something you didn't want to let get fat because it was nearly impossible to get the fat out of/off of again. I've always remembered that, so the info was out there some place, even then!


for the past several weeks, I have had right abdominal pain off and on, until finally was acute. All scans and tests were negative. Exploratory surgery showed part of the omentum had twisted and died and attached to my gall bladder. The surgery removed "dead" portion. Could I have died if not found?


I had what was suppose to be exploratory surgery for chronic abdominal pain and awoke to find that I had two feet of colon removed and a softball size of omentum. That was in 2007 and to this day I have chronic pain and have tried a multitude of drugs, therapies and remedies,without any relief. I had never heard of the omentum in my life and still don't understand its function.


I had surgery in 1995. Due to infection I lost my sternum. The doctors pulled my omentum up to provide some chest protection. something is pushing against my lung diaphragm and causing breathing problems. could this be the problem.


The number of organs, glans and such that the layman has not heard of far out weighs the number that they have heard of. Putting that fact aside.

Doctors and scientists are learning new things about the human body all the time, new relationships between organs, new roles that hormones play. There are still many mysteries or else diagnosis and treatment would not be so hit-and-miss.


I'm having a hysterectomy next week and they are removing my omentum as well. There is cancer in my ovaries and the omentum. Also, more on the peritoneal wall.

I'd never heard of the omentum before my diagnosis either. Judging by the pics, who'd want to know about it? Even the healthy one looks like a chicken's skin. Not to make light, but yuck!

All the other posters with cancer - you are in my thoughts.


If stress can cause the omentum to increase in size, could this possibly be a connection to the weight gain when someone stops smoking?


I was hospitalized recently for a severe pain in the right upper quadrant of the abdomen. The CT radiologist determined it to be an omental infarction. I've had had three similar pain previously dating back to 1968. Finally, I know what they were.


is there any sudden intense pain lasting just seconds-a feeling of tearing ?


I have Uterine Sarcoma Cancer. I had a complete hysterectomy in June of 2007. In May of 2008 I had another surgery to remove a tumor that was in my omentum. In March of this year, I once again had to have surgery. Another tumor in the omentum. They removed the omentum this time. I just pray to god that no tumors come back, because where will it be this time??


I heard of someone who had a bad car accident. She had surgery on her omentum and spleen, however, over time her omentum is dropping. Are there any exercises she can do to help this problem without surgery? Would pilates do anything for her?

Thank you for your consideration in answering this.


To the "Lamaestra's" of the world, *please* look something up before you accuse someone of being wrong or "making" something up. Dr. Oz *knows* what he is talking about.

Anyone with symptoms of (Ascities) fluid or enlarging of the abdomen should seek immediate consultation from a specialist. My Mother was 4 to 6 months with abdomen pains and then sudden enlargement of her tummy area. After MRI's, CAT scans and a colonoscopy she was then drained of the fluid that was gathered in her abdomen. In that fluid was found cancer cells. She was then diagnosed with stage 4 Ovarian Cancer. She had surgery @ Brighams & Womens in Boston with the removal of her Omentum, ovary and fallopian tubes. She is now receiving Chemotherapy. The Omentum is a very important organ to the abdomen.

Just remember that in this day of technology we are now hearing new words and information we never heard before. It doesn't mean everything you hear is true but seriously; is a well known doctor going to stand on a national television show like Oprah and lie to us...I don't think so. Plus, look it up or ask your doctor if it's true. Don't post something you have no idea what your talking about.


My omentum was removed because of possible uterine cancer that metastasized(i had tumors outside and inside my uterus). I did have cancer but in the lung. I have constant pain in the upper/lower quadrants of my midsection, could this be related to scar tissue from the removal of the omentum?

I had ultrasounds and a pet scan. They came out okay, but I still have pain and discomfort. Thank You, Marie


in the past doctors were not expected to tell folks about omentums and other important body factors more recently, people are taking control of their own bodies and are wanting to know exactly what is going on


Working with peritoneal dialysis patients on a daily basis makes a person acutely aware of the omentum as an organ that is both beneficial and sometimes troublesome.


Lamaestra! Dr. Qz made it up!! Duh - that's a pretty dumb and "dangerous" statement don'cha think?

I had never heard of it either - my first knowledge was today after a CT Scan. Thankfully my daughter had watched Dr. Oz and therefore, knew what the Dr. was talking about and could ask the proper questions. In the last two weeks my stomach has 'bloated' up with fluid - now I'm on the fast track to see some specialists.

Don't be so cavalier with your statements - this is serious!!



I don't understand - if the omentum is such a vital organ, why did none of us ever hear about it before Dr. Oz? I hate to be that cynical, but it seems a little like he made it up on the spot!


My father had thickening and hardening of his omentum (and build up of fluid in abdomen known as ascites) which we teased as his beer belly. Any unusual expanding of the abdomen causing discomfort should be brought to the attention of a doctor. This incidental finding during another test is the sole reason he found out he has metastatic cancer (at this time of unknown primary source). Please let your readers know this important fact....it's not just about weight loss!

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