Diverticulitis is a type of disease that affects your digestive tract. It’s a serious medical condition that causes inflamed pouches in the lining of your intestine. These pouches are called diverticula. They develop when weak spots in your intestinal wall give way under pressure, causing sections to bulge out.

In most cases, the pouches occur in the large intestine, which is also called your colon. Diverticula often exist without infection or inflammation. This condition is called diverticulosis, a less serious condition than diverticulitis. Diverticulosis becomes more common as you age, occurring in about half of Americans over age 60.

With diverticulitis, these diverticula are inflamed or infected, or they may tear. Diverticulitis may lead to serious health problems or complications, including:

  • nausea
  • fever
  • severe abdominal pain
  • bloody bowel movements
  • abscess, or an inflamed pocket of tissue
  • fistula

Your diet can affect your symptoms of diverticulitis. Read on to learn about certain foods you might want to avoid, and how your diet should vary when you’re having symptoms and when you’re not.

Because the exact root cause of diverticulitis isn’t yet known, there’s no list of foods that are known to ease symptoms of this condition. Also, the National Institutes of Health states that you don’t need to avoid certain foods if you have diverticulitis.

However, you may want to consider keeping certain foods to a minimum. Talk to your doctor about whether you should avoid the following foods or reduce the amounts you consume.

High-FODMAP foods

Research has found that a diet that limits foods that are high in FODMAPs — fermentable oligosaccharides, disaccharides, monosaccharides, and polyols — can benefit people with irritable bowel syndrome. Researchers have suggested people with diverticulitis may also benefit from this diet.

Some examples of foods high in FODMAPs include:

  • certain fruits, such as apples, pears, and plums
  • dairy foods, such as milk, yogurt, and ice cream
  • fermented foods, such as sauerkraut or kimchi
  • beans
  • cabbage
  • Brussels sprouts
  • onions and garlic

High-fiber foods

Foods that are high in fiber may be helpful for people with diverticulosis who aren’t having an acute flare up and may even help prevent diverticulitis in the first place.

A 2017 systematic review of studies on diverticulosis and the occurrence of acute diverticulitis showed a “reduction of abdominal symptoms and the prevention of acute diverticulitis” with the intake of fiber.

However, every individual is different, and your specific fiber needs will vary based on your condition and symptoms. If you’re having pain or other symptoms, your doctor may suggest that you limit your intake of these foods for a while.

Fiber adds bulk to stool and may increase peristalsis or colon contractions. This may be painful and uncomfortable if you’re having a flare up.

Avoiding high-fiber foods, particularly if you’re inflamed, may ease symptoms and give your system a temporary rest. In addition, whether including higher or lower amounts of fiber, you should also drink plenty of water.

Fiber-rich foods you might want to limit or avoid, especially during a flare up, include:

  • beans and legumes such as navy beans, chickpeas, lentils, and kidney beans
  • whole grains such as brown rice, quinoa, oats, amaranth, spelt, and bulgur
  • vegetables
  • fruits

Foods high in sugar and fat

A standard diet high in fat and sugar and low in fiber may be linked with an increased incidence of diverticulitis. Research suggests that avoiding the following foods may help prevent diverticulitis or reduce its symptoms:

  • red meat
  • refined grains
  • full-fat dairy
  • fried foods

Other foods to avoid

In the past, doctors recommended that people with diverticulitis avoid eating nuts, popcorn, and most seeds. It was thought that the tiny particles from these foods might get lodged in the pouches and lead to an infection.

More recently, most doctors have moved away from this advice. Modern research has shown no evidence linking those foods with increased diverticular issues.

Some research has also suggested that people with diverticulitis avoid alcohol.

Treatment and disease management approaches for diverticulitis vary from person to person. However, your doctor will likely suggest that you adopt certain dietary changes to make the condition easier to tolerate and less likely to worsen over time.

If you’re having an acute attack of diverticulitis, your doctor may suggest either a low-fiber diet or a clear liquid diet to help relieve your symptoms. They may recommend following one of these diets until you’ve recovered.

Low-fiber foods

Low-fiber foods to consider eating if you have symptoms of diverticulitis include:

  • white rice, white bread, or white pasta, but avoid gluten-containing foods if you’re intolerant
  • dry, low-fiber cereals
  • processed fruits such as applesauce or canned peaches
  • cooked animal proteins such as fish, poultry, or eggs
  • olive oil or other oils
  • yellow squash, zucchini, or pumpkin: peeled, seeds removed, and cooked
  • cooked spinach, beets, carrots, or asparagus
  • potatoes with no skin
  • fruit and vegetable juices

Clear liquid diet

A clear liquid diet is a more restrictive approach to relieving diverticulitis symptoms. Your doctor may prescribe it for a short period of time. A clear liquid diet usually consists of:

  • water
  • ice chips
  • ice pops with frozen fruit puree or pieces of finely chopped fruit
  • soup broth or stock
  • gelatin, such as Jell-O
  • tea or coffee without any creams, flavors, or sweeteners
  • clear electrolyte drinks

Other dietary considerations

Whether on a clear liquid diet or not, it’s generally helpful to drink at least eight cups of fluid daily. This helps keep you hydrated and supports your gastrointestinal health.

Be sure to talk with your doctor before making any dramatic dietary changes. After your condition improves, your doctor may recommend slowly adding low-fiber foods back into your diet. Once you no longer have symptoms of diverticulitis, your doctor may suggest that you resume a balanced diet.

Even though avoiding high-fiber foods can help relieve symptoms of diverticulitis, research has shown that regularly consuming a high-fiber diet with lots of vegetables, fruits, and whole grains may reduce the risk for acute diverticulitis.

Since fiber can soften your body’s waste material, softer stool passes through your intestines and colon more quickly and easily. This, in turn, reduces the pressure in your digestive system, which helps prevent the formation of diverticula, as well as the development of diverticulitis.

A high-fiber diet is often one of the first things a doctor will recommend if you have diverticulosis or you’ve recovered from diverticulitis.

If you’re not already consuming high-fiber foods, be sure to start slow when adding them to your diet. One study found that those who consumed at least 25 grams of fiber per day had a 41 percent lower risk for developing diverticular disease, compared with those who only consumed 14 grams.

For people without diverticular issues, eating a diet that’s rich in fiber helps promote a healthy digestive system.

Research also shows that gut bacteria play a role in diverticular disease. Though more research is needed, future studies are likely to support the modulation of gut bacteria through a high-fiber diet and probiotic supplementation.

If you’ve been given a diagnosis of diverticulitis, talk with your doctor about your food needs and food restrictions. It’s important to discuss how food may heal and possibly aggravate your condition.

In general, if you have diverticulosis but you’re not having a diverticulitis episode, a diet high in fiber will help prevent future flare-ups. Depending on the severity of an acute diverticulitis flare-up, a diet low in fiber or a clear liquid diet may be beneficial to reduce symptoms.

If you need additional guidance, ask your doctor to refer you to a dietitian. Specifically, seek out a healthcare professional who has experience working with people who have diverticulitis. They can help you find ways to enjoy the high-fiber foods you need in your diet.

In addition, stay in communication with your doctor about your condition. While diverticulitis may remain dormant for long periods of time, keep in mind that it’s a chronic, lifelong condition.

If you start to notice your symptoms increasing, have a plan of action ready from your doctor that can reduce pain and discomfort and help you manage your condition.