“Diverticulosis happens when the lining of the colon pokes through the muscles on the outside of the colon, causing these pockets that look like indentations,” explains Lisa Strate, section head of gastroenterology at Harborview Medical Center at the University of Washington.

And while diverticulosis is common, it’s mostly inconsequential.

“At least 50 percent of us will get it as we age,” says Strate. “But diverticulosis itself is asymptomatic. Fewer than five in 100 patients will ever have a problem.”

What is diverticulitis?

Diverticulitis is a different animal. “That’s where one or a couple of the pockets get inflamed,” Strate explains. And diverticulitis can result in pain in the lower abdomen, constipation, or diarrhea.

Who’s at risk for diverticulitis? “It is estimated that approximately 50 percent of a person’s risk is genetic,” notes Strate.

But lifestyle factors also matter. “People who aren’t physically active, those with obesity, smokers, or those who take non-steroidal anti-inflammatory drugs are all more likely to get diverticulitis,” says Strate.

Do certain foods lead to diverticulitis?

“We’ve found that people who eat a Western diet—which is high in red meat, refined grains, and high-fat dairy—are much more likely to get diverticulitis than people who eat a diet that’s rich in fruits, vegetables, and whole grains and low in red meat,” says Strate.

If you do have diverticulitis, one thing you don’t have to worry about: avoiding nuts, seeds, and popcorn.

“That seems to be a bit of folklore,” says Strate. “When you look at the colons of people with diverticulosis, there are little balls of stool that get stuck in the pockets. It was assumed that nuts, seeds, and popcorn were likely to get stuck and cause trauma that led to diverticulitis.”

To find out, Strate followed roughly 47,000 men for 18 years. “We actually found that the risk for diverticulitis was lower—not higher—in those who ate a lot of nuts and popcorn.”

That kind of study can’t prove that eating nuts or popcorn lowers risk. Something else about people who eat those foods may explain their lower risk.

“We hope that in the near future there will be randomized trials that more rigorously test how diet impacts the likelihood of developing diverticulitis,” says Strate. Stay tuned.