A healthy omentum is slightly transparent, almost lacy looking. An unhealthy omentum can be 3x, 4x, or even larger, than the healthy organ. Fat cells extend the organ to make it seem a globular, weighty mass. A person doesn't have to be extremely overweight to have an overly large omentum.
Healthy omentum held by Oprah. The unhealthy omentum held by Dr. Oz is from a man who was only 30 lbs overweight!
The omentum is a fat organ connected to your stomach. Its general purpose is to catch and store fat. When stored in your stomach your body has easy access to the fat. It also stores hormones, including cortisol - also known as a "stress hormone". I guess that is part of the reason stress and belly fat are often connected.
For people with high stress, diet and exercise alone do not often work to reduce the size of a person's omentum. Often stress relievers such as meditation or yoga are advised.
If you did happen to catch Dr. Oz's spiel about the omentum you may be thinking that it serves no real purpose. However the presentation was a bit oversimplified. The omentum has more to do with our bodies than simply store fat.
Sometimes described as a "fatty apron" the omentum helps to cushion and protect our organs. It also has nutrients and growth-stimulating chemicals as well as stem cells. And the omentum has germ-fighting cells that migrate to places of infection within the abdomen. It will adhere to places of infection, effectively sealing them off.
So yes your omentum is a valuable part of your body. However an over sized, fatty omentum is not healthy. As well as looking unsightly (ie creating a "beer belly" bulge) it can lead to diabetes, hardening of the arteries and high blood pressure. Even more disturbing is that it can push other organs out of place as it expands.
This was of personal concern to me. I tend to carry most of my weight in my belly. My legs aren't fat, my butt isn't fat, my arms are okay. I have noticed my face is quite a bit fuller than it used to be but my real "fat stores" are my stomach and my breasts. I guess I need to add yoga to my 'get healthy plan'!