How big can the human stomach expand?

An adult's empty stomach is as large as a 0.5 liter can of soda and can expand to the size of a 2 liter bottle, some even up to 4 liters.

After enjoying a big meal, the eater will feel his stomach is bigger and his pants are tighter than before. So how much can the stomach expand?

An adult's empty stomach is like a folded bag about the size of a 0.5-liter can of soda, and during a meal it can grow to the size of a 2-liter plastic bottle, according to Arthur Beyder, associate professor of medicine and physiology at the Mayo Clinic.

'It will expand four times or more , ' says Beyder. For most adults, this means the stomach can hold 1 to 2 liters of food and liquid, depending on age and body size. In extreme cases, such as in competitive eaters, the stomach can expand to hold 4 liters.

The stomach can expand four times when full. (Photo: New York Post).

A 2018 study in the journal Gastroenterology documented the case of a compulsive eater who ended up in the emergency room after overeating to the point where his stomach expanded, compressing his pancreas and pushing his intestines to one side. After five days in the hospital, the person was able to pass gas and have a bowel movement, meaning he was fit to be discharged.

Overeating also happens frequently during parties, when stressed, or when distracted by watching TV, says Benjamin Levy, MD, a gastroenterologist at the University of Chicago Medicine. 'They get distracted, and before they know it, they've overeaten,' he says.

Hunger is stimulated by the hormone ghrelin. This hormone is secreted primarily by the stomach , but also by the brain, small intestine, and pancreas, according to the Cleveland Clinic. Ghrelin is released when the stomach is empty to alert the brain that it's time to eat.

When a person begins to eat, food travels down the esophagus and into the stomach. Folds called rugae allow the stomach to expand to accommodate the food and liquid. As the food enters, the stomach secretes hydrochloric acid and digestive enzymes. This organ also begins to contract, breaking the food into smaller pieces so that nutrients can be absorbed later, in the small intestine.

The stomach is made of smooth muscle, which can tighten and maintain contractions for long periods of time, even after it has relaxed. This allows the stomach to make room for more food.

'It's almost like a rubber band, you pull it and it snaps back ,' says Beyder. This is called muscle tone , which helps control how much your stomach stretches. Stomach stretch is transmitted to your brain via the vagus nerve, which runs from your large intestine to your brain, according to the Cleveland Clinic. This is just one of the ways your brain communicates how full your stomach is.

There are also hormonal changes that signal the brain when to stop eating. The hormone ghrelin decreases, while other hormones signal fullness to the brain and reduce appetite. If a person overeats, they may ignore these signals, or eat so quickly that the hormones do not have time to signal the brain.

The trick is to eat slowly, Levy says. 'Sit there and talk for 15 minutes before going back for more food ,' he says. Although the stomach is designed to expand and hold a lot of food, people feel better if they don't overeat, Levy says.

But if you're too full, there are a few things you can do to ease the discomfort . First, don't lie down, which can cause acid reflux. Instead, Levy recommends walking. This helps stimulate digestion and moves food through the digestive system.