UCSD doctor brings erudite air to Rancho Santa Fe Senior Center discussion of digestion


There was an attentive silence as Terrie Litwin, executive director of the Rancho Santa Fe Senior Center, introduced Dr. Joseph Weiss to the senior center guests. That silence soon erupted into laughter as Weiss — an award-winning speaker — educated and entertained the audience through his effervescent presentation on flatulence.

Titled “To Air Is Human,” Weiss’s March 25 program covered many aspects of digestion, observing that “People burp, belch, have bloating and pass gas and no one ever talks about it in an intelligent way.”

Weiss, a clinical professor of gastroenterology at UC San Diego, set out to change all that as he shared his topic with humor and wisdom, using comedic illustrations and off-beat anecdotes that included poking fun at British royalty, the Dalai Lama and Benjamin Franklin.

Stating that he has an interest in things that are “a little eccentric and a little different,” Weiss — whose undergraduate majors included medieval English literature and astrophysics — joked that his interests “are extremely wide but run about an inch deep.”

By giving a schematic tour of the digestive tract, Weiss explained in layman terms the whole process of digestion and how gas is produced.

“Digestion is much like going through a disassembly line,” he explained. “You take things in your mouth, and your body takes them apart so it can extract the nutrients you need.”

Food enters the stomach where hydrochloric acid breaks it down. It then passes into the small intestine, which helps neutralize the food using sodium bicarbonate secreted by the pancreas. This is where liters of carbon dioxide are created, bloating the gut, an effect experienced by everyone. “After a heavy meal, you may have to loosen your belt as you feel like you have gone up a size or two,” said Weiss.

The colon, with massive surface area through its villi and tissue folds, moves the waste out as feces, “which is not an English word,” noted Weiss as an aside.

“The proper English word for excrement is ‘shyt’ and has been used for hundreds of years, so you can use it without embarrassment,” he quipped.

Well-known is that the end of digestion for humans is “poop,” but the story does not end there, said Weiss. “For some animals, it’s their next meal, and they love it!”

Foods and habits that humans should avoid — as they create more gas than the normal 11.5 farts a day for the average adult — include chewing gum or hard candies, smoking cigarettes, chewing tobacco, eating ice cream, bread and apples (each made mostly of air), and drinking through a straw, which each result in more air being swallowed.

Some foods relax the lower esophagus sphincter muscle, which produces heartburn and acid reflux along with an increase in gas. These include alcohol, caffeine, tobacco, chocolate, fried foods, fatty foods and peppermint.

“There is a reason why restaurants offer you a mint on your way out,” joked Weiss.

Along with the levity, Weiss also touched on the serious topic of the importance of colonoscopies for detecting polyps — precursors to colon cancer — and the breakthrough science that has invented early detection methods that are non-invasive.

Weiss’s erudite yet humorous facts can be found in his books, “To Air Is Human: Everything You Ever Wanted to Know About Intestinal Gas”; “Artsy Fartsy,” a cultural history of the fart; “You Don’t Know Sh*t!” which looks in depth at human waste. Coming soon is “How Do You Doo? Everyone Has to Poo!” a guide to toilet training.

Weiss has been invited to present another program at the senior center on June 3 titled “Gut Instincts: Genes, Microbes and the Brain.”

There is new scientific understanding that the gut actually is a “second brain” and plays a vital role in physical and mental health. Weiss will explain how our genes, the microbes that live in and on our body, the gut nervous system and brain are all intimately intertwined and influence each other.

Visit to learn more about Weiss or to buy his books.