 Researchers in Sweden found that smoking might cause an increase in visceral fat. That's the worst kind of fat. It's not visible, but rather it's deep under your skin, enveloping your organs and resulting in a lot of inflammation, which can lead to a host of chronic diseases. When you make the decision to quit smoking, keep in mind that your body reaps the rewards almost instantaneously. I'm Dr. Sanjay Gupta, helping you live a better life.