Ask the Experts

Body Fat: The Good, the Bad, and the Ugly
Jillian Michaels

You know that junk you have in the trunk — that extra padding you hate on your hips and butt? You may not like the way it looks, but it's not necessarily bad for you. The fat surrounding your gut, though, is a different story — in fact, it can be deadly.

Let's start with the "good" fat — the fatty layer just beneath your skin in the lower half of your body. It's called subcutaneous fat, and it's not necessarily the worst thing to have. Subcutaneous fat gives rise to two beneficial metabolic hormones: leptin, the hormone that tells your body to hang onto or let go of weight, and adiponectin, a hormone that lowers your blood sugar. A Harvard study found that subcutaneous fat might help improve sensitivity to insulin and prevent diabetes.

The fat in your stomach area, on the other hand, is bad news. Known as visceral fat, it's hidden deep down, so even if you don't have a protruding belly (a signal for some that they have it), you could still harbor this "bad" kind of fat. Visceral fat lies far beneath your skin, where it surrounds your organs and sets off a harmful hormonal firestorm. Having this metabolically horrific fat slows your metabolism, lowers growth hormone, raises cortisol, creates insulin resistance, and increases your risk of all kinds of diseases, including diabetes, heart disease, high blood pressure, and fatty liver disease.

You increase your risk of having visceral fat when you're overweight, so how can you lose it? Diet and exercise! Taking care of yourself will reduce visceral fat and lower your risk of all the health problems associated with it.