I coined that phrase. Dontcha love it? What I’m talking about is the increasingly common “beer belly” on men of a certain age -- men who look nine months pregnant before the baby has “dropped:” A high, hard abdomen, which is actually your peritoneal cavity filled with visceral fat around your organs. Your jacket button doesn’t button any more. You can’t hug without first bumping into the huggee. I know. I was “there” once, before I lost 170 pounds.
I first came across the noun form “omentum” about 2005 in, “You on a Diet,” a book by a Canadian doctor, Michael Roizen, popularized by Oprah and a PBS series. The omentum is a sheet of fat that is covered by the peritoneum. The greater omentum is attached to the bottom edge of the stomach, and hangs down in front of the intestines. The other edge attaches to the transverse colon. The lesser omentum is attached to the top edge of the stomach, and extends to the undersurface of the liver. In humans, especially men who make bad food choices, the omentum is a mass of fat around and especially in front of the stomach, liver, spleen, pancreas, kidneys and intestines.
This “visceral fat, also known as organ fat or intra-abdominal fat, is located inside the peritoneal cavity, packed in between internal organs and torso. It is differentiated from subcutaneous fat which is underneath the skin, and intra-muscular fat which is interspersed in skeletal muscle. Other distinctly different types of body fat include bone marrow fat and epicardial fat, which is deposited around the heart and found to be a metabolically active organ.
The common understanding of obesity is a net energy imbalance. The fundamental cause of obesity, however, is a metabolic disorder of fat regulation. There is a growing consensus that, in humans, central obesity is related to the excessive consumption of fructose. It is also associated with elevated levels of the hormone insulin. In a large study (NHANES III), excessive waist circumference appears to be more of a risk factor for metabolic syndrome than BMI (Body Mass Index). The Central Obesity Index (CBI) is another measure more predictive of increased risk than BMI.
Central obesity is associated with a statistically higher risk of heart disease, hypertension, insulin resistance, and Type II diabetes. Belly fat is a symptom of Metabolic Syndrome. (Scroll down to see Retrospective #9). Central obesity is also associated with glucose intolerance and dyslipidemia (“high cholesterol”), as well as a group of diseases that are either inherited or due to secondary causes (Cushing’s syndrome, PCOS, and treatment for AIDS).
Central obesity is known to predispose individuals for insulin resistance and Type 2 diabetes. Discoveries in recent decades have revealed that abdominal fat is especially active hormonally, secreting a group of hormones called adipokines that may possibly impair glucose tolerance. Central obesity seems to be the foremost type of fat deposit contributing to rising levels of serum resistin, one such hormone. Conversely, serum resistin levels have been found to decline with weight loss, especially decreased central obesity. Central obesity is metabolically very unhealthy!
Of course, there are sex differences in fat accumulation. Female sex hormones cause fat to be stored in the buttocks, hips and thighs. Men are more likely to have fat stored in the belly. When a woman reaches menopause and estrogen production declines, fat migrates from the buttocks, hips and thighs to the waist and belly.
So, what can be done about “omental adiposity”? Low fat and restricted calorie diets have not proven to be an effective long-term intervention. Most people regain the weight that was lost and many regain still more. Spot exercises, such as sit-ups, crunches and other abdominal exercises are useful in building abdominal muscles, but they have little, if any, effect on the adipose tissue located there. And, just for the record, there is little evidence that beer drinkers are more prone to abdominal adiposity than non-drinkers or drinkers of wine or spirits.The best way to lose and keep off excess omental weight – the “pot belly” – is a diet that provides satiety (a high fat diet), that digests slowly and restores skeletal muscle (moderate protein), and that allows you to burn body fat for energy. That diet is a low carbohydrate diet. See Retrospective #11 (scroll down), or, on Facebook, search my Time Line. After the body burns the “sugars” (glucose) in carbs for energy, it turns to fat for energy, both dietary and body fat. I know. I’ve regained some of the 170 pounds that I lost, but I have lost my “beer belly” forever.