When many of us think of fat, we picture folds and rolls that jiggle. The fat that the health and beauty industries market toward is that which is under the skin, otherwise known as subcutaneous fat. It’s the same fat that puckers through weak connective tissue grids creating what we call cellulite. While this fat is concerning from both an aesthetic and health oriented perspective, there is a far more insidious kind of fat not always visible on the outside who is responsible for a host of diseases in the long term. This fat is not assessed by volume like those caliper pinching tools used to tell you your overall body fat %, but by location. This is your deeper fat reserve – your visceral fat.
Visceral fat (also known as brown fat or metabolic fat) gets its name because of where you find it – nestled deep in the abdominal cavity surrounding organs (i.e. viscera) like the liver, intestines, pancreas and kidneys. It’s there as an energy back up for your vital organs as well as to cushion and protect them. Your body is hardwired to maintain this fat, unless there is a deficit (i.e. starvation or intense exercise). In fact, even when not starving, this fat produces substances that affect insulin levels and communicate with the liver to influence blood fat content ensuring that the vital organs always get fed. In a famine, this fat will be the first to go before your body resorts to breaking down surface fat, muscles and organs for fuel. Now, imagine that you have more than what you need of this highly active fat? It pumps out pro-inflammatory cells into your blood stream, since it has a tight relationship with a major blood vessel to the liver and heart. These cells cause insulin resistance which is the precursor to Type II diabetes as well as promote the development of heart disease, atherosclerosis (hardening of the arteries) and cancer of the bowel. Research even suggests that visceral fat increases production of the stress hormone, cortisol, and reduces levels of feel-good endorphins, leaving you feeling low on so many levels.
Being that it is so metabolically active, plentiful visceral fat is not the easiest to get rid of. This is also why people who have excess are now being termed metabolically obese regardless of whether they look lean or large. The tell tale sign of this excess in most people is the gut. While the gut is more prevalent in men who tend to have more fat stores in their belly region due to their hormones, menopausal women can also display this type of distention. Waist circumference will give you an inkling as to whether visceral fat is high; 35 inches or more in women and 40 inches and above for men. Another factor that affects visceral fat accumulation beyond gender and hormones is heredity/ethnic background. If people in your family tend to be apple shaped, meaning that more of their fat resides in the upper body, chances are your visceral fat is going to be higher. Following patterns amongst ethnic groups, it was found that excess visceral fat pops up in white men, African American women, Asian Indian and Japanese men and women most often. In addition, certain environmental factors play a role such as smoking and the consumption of compounds in food that mimic estrogen. Known as xenoestrogen or “foreign estrogen” they enter the body through the eating of plants and meats that have been exposed to or naturally contain these compounds and wreak havoc on hormonal levels which mess with visceral fat accumulation. However, many people suffer from metabolic obesity, as I noted earlier, without any outward sign of a large tummy. In fact, they might look pretty lean to the naked eye and register BMI’s that are in normal range. The only way they find out their visceral fat is high is through an MRI or CT like scan, where the fat’s location can be clearly seen, as demonstrated in the below image. Of course, this is a costly test that is not always accessible or covered by insurance.