Surprising Facts About Your Stomach

When you swallow food, it enters your esophagus. That’s a stretchy tube about 10 inches long that connects the back of the throat to the stomach. It’s narrow, but the muscles in its walls slowly squeeze food down and through. This is called peristalsis. It normally takes just a couple of seconds for each bite.

Digestion begins in the mouth. Chewing and exposure to saliva is the first step in breaking down food. Food and drinks mix with gastric juices. This creates a mixture called chyme. That’s dumped into the small intestine, where most of the digestion takes place. From there, food is dissolved, nutrients are absorbed into the body, and waste is sent to the colon.

No exercise can change the size of your actual stomach. When it’s empty, it’s only about as big as a fist. Planks, sit-ups, and crunches can tone your abdominal muscles, which lie between your stomach and your skin. But even that may not give you visible results. To really "lose your belly," you need to shed the layer of fat that sits on top of your ab muscles. Any kind of workout that gets your heart rate up and burns calories will help. So will eating fewer calories.

One in 6 Americans gets sick every year from contaminated food. Norovirus, also called the stomach flu, causes swelling in the stomach and intestines. That leads to pain, nausea, diarrhea, and vomiting. Some foods -- like oysters, fruits, and vegetables -- can be contaminated naturally. They can also be tainted by an infected person, like a restaurant cook or server. Harmful bacteria, like E. coli, salmonella, and listeria, are also common sources of food poisoning.

Soluble fiber is found in oat bran, peas, beans, and most fruits. Bacteria in your large intestine break it down and digest it. In about one-third of people, it creates methane gas. That can make you burp, fart, or feel bloated. Insoluble fiber is found in wheat bran and some vegetables. It’s not digested by the body. It passes through the intestines unchanged, so it makes little gas.

Ever finish your morning cup of joe only to find yourself running to the bathroom? If so, it's not just you. According to the American Chemical Society, coffee has this effect on about 30% of people. It's not the caffeine. Scientists believe a compound in the drink causes the stomach to make extra gastric acid. That can cause it to dump its contents into the intestines earlier than it normally would. Coffee has also been shown to increase digestive hormones in the intestines, which help move waste along.

Gastroesophageal reflux disease (GERD) happens when the stomach's contents flow backward into the esophagus. If you’re overweight, dropping some pounds can relieve some of the pressure on your stomach. If you get acid reflux when you lie down at night, raise the head of your bed. Gravity can help keep stomach acid down. One study found that eating four to five small meals a day relieved symptoms better than three large ones. If these things don't help, talk to your doctor about treatment options.

They pass through your stomach and small intestine much faster than protein or fat. Simple carbs, like fruit juice and table sugar, travel fastest, followed by complex carbs like those found in whole wheat bread and vegetables. Your body has to break down protein before it can digest it. Fat takes the longest to process, but it supplies the body with more than twice the calories as either protein or carbs.

They may irritate your stomach if you have an ulcer, but there’s no research to prove they cause it. A reason you might want to avoid soda: Soft drinks, both regular and diet, have been linked to increased belly fat. Usually, ulcers form because of an infection with the bacteria Helicobacter pylori (H. pylori) or because of damage from long-term use of drugs like aspirin and ibuprofen.