When you’re not in a flare, eating a high-fiber diet can promote gut health and reduce flares. However, switching to easier-to-digest foods during a flare may help relieve symptoms.

Diverticulitis is a condition that affects the digestive tract. It’s an infection of the diverticula. These are small pockets that develop in the lining of the intestine.

Diverticula develop when weak spots in the intestinal wall give way under pressure, causing sections to bulge out. The presence of diverticula is called diverticulosis. It’s when they become inflamed or infected that it is considered diverticulitis.

Diverticulosis is more common in older adults. Around 58 percent of people over age 60 have diverticulosis, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diverticulitis is not as common: Less than 5 percent of people with diverticulosis will develop diverticulitis.

Diverticulitis may lead to health problems or complications, including:

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

Doctors used to recommend a low fiber, clear liquid diet during diverticulitis flare-ups.

However, some experts no longer believe that you have to avoid certain foods when you have diverticulosis or diverticulitis.

That said, management of diverticulitis depends on the person. Some people may find that avoiding certain food helps.

Some doctors still recommend a clear liquid diet during mild flare-ups. Once symptoms improve, they may recommend moving on to a low fiber diet until symptoms disappear, then building up to a high fiber diet.

The following sections look at the research behind different foods you might want to avoid with diverticulosis or diverticulitis.

High FODMAP foods

Following a low FODMAP diet has benefits for some people with irritable bowel syndrome (IBS). It may also help some people with diverticulitis.

FODMAPs are types of carbohydrate. It stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.

Some researchers suggest that a low FODMAP diet could prevent high pressure in the colon, which, in theory, could help people avoid or correct diverticulitis.

In this diet, people avoid foods that are high in FODMAPS. This includes foods such as:

  • 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
  • legumes
  • foods high in trans fats
  • soy
  • cabbage
  • Brussels sprouts
  • onions and garlic

Red and processed meat

According to a 2018 research article, eating a diet high in red and processed meats could increase your risk of developing diverticulitis. A diet high in fruits, vegetables, and whole grains may decrease the risk.

Foods high in sugar and fat

The standard Western diet is often high in fat and sugar and low in fiber. Because of this, it may increase a person’s risk of developing diverticulitis.

A 2017 study involving more than 46,000 male participants suggests that avoiding the following foods may help prevent diverticulitis or reduce its symptoms:

  • red meat
  • refined grains
  • full fat dairy
  • fried food
Summary

According to some research, avoiding red meat and foods high in FODMAPs, sugar, and fat can help prevent diverticulitis flare-ups.

The effect of fiber on diverticulitis can vary from person to person. In the past, doctors recommended that people with diverticulitis follow a low fiber diet or a clear liquid diet. Today, some doctors have moved away from this advice.

Dietary fiber can reduce the symptoms of diverticular disease and improve bowel function, according to research from 2018. Researchers stated this is because fiber can improve colon health by allowing better gut movement and stool bulk.

Some studies suggest that low fiber diets can even increase the risk of diverticulitis, along with high meat intake, low physical activity, and smoking.

  • 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

While some researchers have linked a high fiber diet to a reduced risk of diverticulitis, this may not be helpful for someone experiencing diverticulitis flare-ups.

Fiber adds bulk to the stool and may increase colon contractions, which can be painful during a flare-up. Your doctor might recommend avoiding fiber during an acute flare.

Each person is different. It’s always a good idea to consult a medical professional before making large diet changes.

When adding fiber to your diet, be sure to drink plenty of water to avoid constipation.

Summary

When you’re not having a diverticulitis flare-up, a high fiber diet can reduce the risk of flares and help keep the gut healthy.

In some cases, your doctor might suggest certain dietary changes to make diverticulitis 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.

Once symptoms improve, they may recommend sticking with a low fiber diet until symptoms disappear, then building up to a high fiber diet to prevent future flares.

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 foods that contain gluten 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 without skin or seeds
  • 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
  • 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 you’re on a clear liquid diet or not, it’s helpful to drink plenty of water every day. This helps keep you hydrated and supports your gastrointestinal health.

Be sure to talk with your doctor before making any dramatic dietary changes.

If you’re following a clear liquid diet, after your condition improves, your doctor may recommend slowly adding low fiber foods back into your diet, building up to a high fiber diet.

Summary

During a diverticulitis flare, a low fiber or clear liquid diet can help ease symptoms for some people.

Even though doctors may recommend avoiding high fiber foods during a flare, the NIDDK recommends regularly consuming a high fiber diet to reduce the risk of acute diverticulitis.

Since fiber can soften your body’s waste material, softer stool passes through your intestines and colon more quickly and easily.

This reduces the pressure in your digestive system, which helps prevent the formation of diverticula.

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

According to a 2016 study, gut bacteria play a role in diverticular disease. Though more research is needed, future studies are likely to support modulating gut bacteria through a high fiber diet and probiotic supplementation.

Summary

Research suggests that eating a high fiber diet can help prevent diverticulitis flares.

In general, if you have diverticulosis but you’re not having an episode of diverticulitis, 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 have diverticulitis, talk with your doctor about your food needs and food restrictions. It’s important to discuss how food may heal or aggravate your condition.

If you need additional guidance, ask your doctor to refer you to a dietitian. Seek out a healthcare professional who has experience working with people who have diverticulitis if you can.

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 condition.