You figure that a few sips of port wine—often served at restaurants as a digestif—won't take up any more room in your stomach. The problem is that port and sherry contain fructose, which can be difficult for your system to absorb, explains Cynthia Yoshida, MD, a Virginia-based gastroenterologist and the author of No More Digestive Problems
. This sugar passes through the small intestine and into the colon, where bacteria break it down and release gas as a by-product. The port won't help with digestion, and, Yoshida says, it can also make you feel gassy and extra bloated.