Diverticulitis Diet: What to Eat During and After a Flare

Why does diet matter in diverticulitis?

Diverticulitis is inflammation of small pouches (diverticula) in the colon wall. During a flare, the colon is irritated and inflamed — passing bulky or hard stool through that segment can worsen pain and delay healing. A temporary diet that reduces stool volume and mechanical demand on the gut allows the inflammation to settle.

Long-term, the Dietary Guidelines for Americans recommends 14 grams of fiber per 1,000 calories consumed (roughly 28 grams per day for a 2,000-calorie diet). A diet low in fiber is associated with the development of diverticular disease, and high-fiber eating is recommended to reduce the risk of future flares 2Ref 2National Institute of Diabetes and Digestive and Kidney Diseases (2021).Eating, Diet, and Nutrition for Diverticular Disease.High-fiber diet recommendations (14 g per 1,000 calories per Dietary Guidelines for Americans) for preventing future diverticulitis flares; high-fiber food examples.

What to eat during an acute diverticulitis flare

Phase 1: Clear liquids (first 1–2 days, or as directed by your clinician)

Clear liquids are transparent, leave virtually no residue in the bowel, and provide fluids and electrolytes 1Ref 1Qaseem A, Etxeandia-Ikobaltzeta I, Lin JS, Fitterman N, Shamliyan T, Wilt TJ (2022).Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis: A Clinical Guideline From the American College of Physicians.Dietary management during diverticulitis flares including liquid diet progression; nuts and seeds restriction not supported by evidence: - Water, clear broth, and bouillon - Plain gelatin (Jello) without added fruit - Popsicles without fruit pieces - Apple juice, white grape juice, or cranberry juice (strained, no pulp) - Sports drinks and oral rehydration solutions - Clear tea or coffee without milk or cream

This phase is typically brief — 1 to 2 days if symptoms are mild. Your clinician will guide the transition.

Phase 2: Low-fiber / low-residue diet (as symptoms improve)

This phase reduces the amount of undigested material traveling through the colon 1Ref 1Qaseem A, Etxeandia-Ikobaltzeta I, Lin JS, Fitterman N, Shamliyan T, Wilt TJ (2022).Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis: A Clinical Guideline From the American College of Physicians.Dietary management during diverticulitis flares including liquid diet progression; nuts and seeds restriction not supported by evidence: - White bread, white rice, plain pasta, and crackers - Eggs, poached chicken, and canned fish - Smooth nut butters (small amounts) - Canned or cooked fruits without skins or seeds (peeled canned peaches, applesauce) - Well-cooked vegetables without skins (peeled zucchini, cooked carrots, green beans) - Low-fat dairy (if tolerated)

Avoid during this phase: raw vegetables, whole grains, high-fiber bread, nuts, seeds, beans, and high-fat or spicy foods.

Transitioning back to a normal diet

As pain, fever, and tenderness resolve — usually over one to two weeks — foods can gradually be reintroduced. Most clinicians advise a slow, staged return to your regular diet rather than jumping directly back to all foods at once 1Ref 1Qaseem A, Etxeandia-Ikobaltzeta I, Lin JS, Fitterman N, Shamliyan T, Wilt TJ (2022).Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis: A Clinical Guideline From the American College of Physicians.Dietary management during diverticulitis flares including liquid diet progression; nuts and seeds restriction not supported by evidence.

Notice which foods cause discomfort during reintroduction. Some people find that certain raw or high-fiber foods remain difficult even after recovery — this is worth discussing with your clinician.

What to eat long-term to prevent future flares

Once fully recovered, a higher-fiber diet is the cornerstone of long-term prevention 2Ref 2National Institute of Diabetes and Digestive and Kidney Diseases (2021).Eating, Diet, and Nutrition for Diverticular Disease.High-fiber diet recommendations (14 g per 1,000 calories per Dietary Guidelines for Americans) for preventing future diverticulitis flares; high-fiber food examples:

• Vegetables: broccoli, leafy greens, carrots, peas, artichokes
• Fruits: apples, pears, berries, prunes, oranges
• Whole grains: oats, whole wheat bread and pasta, barley, brown rice
• Legumes: lentils, chickpeas, black beans, kidney beans

Adults need roughly 25 to 38 grams of fiber per day, depending on age and sex. Most Americans fall well short of this target. Increasing fiber gradually and drinking plenty of water helps prevent the constipation and straining that may contribute to diverticular disease progression.

A note on nuts, seeds, and popcorn For years, people with diverticular disease were advised to avoid nuts, seeds, and popcorn. Current evidence does not support this restriction, and these foods are not prohibited. Discuss with your clinician if you are uncertain 1Ref 1Qaseem A, Etxeandia-Ikobaltzeta I, Lin JS, Fitterman N, Shamliyan T, Wilt TJ (2022).Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis: A Clinical Guideline From the American College of Physicians.Dietary management during diverticulitis flares including liquid diet progression; nuts and seeds restriction not supported by evidence.

Other dietary and lifestyle factors

• Hydration: Fiber absorbs water; drinking enough fluid (at least 6 to 8 glasses per day) prevents fiber from worsening constipation 2Ref 2National Institute of Diabetes and Digestive and Kidney Diseases (2021).Eating, Diet, and Nutrition for Diverticular Disease.High-fiber diet recommendations (14 g per 1,000 calories per Dietary Guidelines for Americans) for preventing future diverticulitis flares; high-fiber food examples.
• Red meat and processed meat: Some evidence links frequent consumption with higher risk of diverticular disease 3Ref 3National Institute of Diabetes and Digestive and Kidney Diseases (2021).Diverticular Disease.Association of low-fiber and high red-meat diet with increased diverticular disease risk; background on diverticulosis and diverticulitis.
• Physical activity: Regular exercise supports healthy bowel function and is generally recommended for colon health.
• NSAIDs: Regular ibuprofen and naproxen use has been associated with diverticulitis risk — discuss alternatives with your clinician if you use them frequently.