Diverticulitis, a condition marked by inflammation or infection of small pouches in the colon wall, often prompts questions about dietary triggers. Dr. Christina Warner, a colorectal surgeon at Houston Methodist, explains, “Diverticulitis begins as a condition called diverticulosis, which happens when sac-like protrusions, also referred to as pouches, form in the wall of the colon. Diverticulosis by itself doesn’t cause symptoms or require treatment. In fact, most people don’t even know they have it.”
Diverticulosis is usually found during routine colonoscopies and does not typically cause symptoms unless one of the pouches becomes inflamed or infected, leading to diverticulitis.
Many people believe that avoiding foods such as nuts, seeds, corn, tomatoes, cucumbers, popcorn, peanuts, and almonds can prevent flare-ups. However, Dr. Warner notes, “Many people who’ve experienced diverticulitis before will say they already know to avoid foods like nuts, seeds, corn, tomatoes, cucumbers, popcorn, peanuts and almonds. This comes from an old theory that small food particles can get trapped in these pouches, leading to problems. But there’s actually no solid evidence to support that claim.”
Instead, she points out that a low-fiber diet may be a more significant factor in triggering diverticulitis. Without enough fiber, the colon’s ability to move waste is impaired, which can result in hard stool and increase the risk of blockage and inflammation. “You can imagine what might happen if a hard piece of stool traveling through the colon were to get stuck in one of these pouches,” says Dr. Warner. “Ventilation becomes blocked, causing mucus and air to build up and eventually leading to inflammation, infection or, in more severe cases, even perforation of the colon lining.”
Research also indicates that the gut microbiome could influence the likelihood of developing diverticulitis. Diet has a significant impact on the gut microbiome’s health, and a poor microbiome may make flare-ups more likely.
When managing a diverticulitis flare-up, Dr. Warner recommends reducing strain on the colon and minimizing inflammation through dietary changes. “Your aim is to reduce the strain on your colon and minimize inflammation,” she explains. “During an attack, we often recommend a liquid diet — or a soft-food diet at the very least. As symptoms are improving, low-fiber foods can slowly be reintroduced.”
She also advises limiting certain gut irritants such as caffeine, alcohol, carbonated beverages, dairy (for those who are lactose intolerant), fatty or spicy foods, red meat, processed meat, and ultra-processed foods. “A more simplified diet means your colon doesn’t have to work as hard, so it can heal,” adds Dr. Warner.
After recovery from a flare-up, prevention focuses on adopting a high-fiber diet and maintaining adequate fluid intake to keep bowel movements regular and reduce the risk of hard stool formation. This involves consuming vegetables, fruits, whole grains, beans, and legumes while reducing red and processed meats. “Beef, pork and lamb can all be pro-inflammatory,” says Dr. Warner. “And processed meats — jerky, sausage, bacon, hot dogs, brisket, smoked turkey and even lunch meats, like ham — contain preservatives that can also contribute to inflammation in the colon.”
Lifestyle changes also play a role in prevention. Smoking cessation and regular physical activity can help lower the risk of recurrence. “Smoking is linked to a higher risk of recurrence, so quitting can make a big difference,” says Dr. Warner. “Staying active and losing weight can also help prevent a future flare-up. If you need help implementing any of these changes, visiting your primary care provider is a good first step.”
