Do you have diverticular disease, or diverticulitis? Learn more about the best diet for diverticulitis, including the role of fibre and supplements, as well as what to do if you’re in a diverticulitis flare, from a gut health dietitian with over a decade of experience and author of Good For Your Gut.

Bestselling author of gut health cookbook, Good For Your Gut, and gut health dietitian with over a decade of experience, Desiree Nielsen RD dishes up evidence-based advice on the best diet for diverticulitis and diverticular disease.

Diverticular disease doesn’t get a lot of attention in gut wellness – we spend a LOT more time talking about low FODMAP diets! – probably because it tends to affect our older population (which is kinda ageist TBH). 

It is true that your risk of diverticular disease jumps after age 55: perhaps 50% of Americans over 60 have diverticular disease. But real talk: diverticular disease is also on the rise in those over 40, making it one of the most common digestive conditions out there! And it doesn’t just come out of nowhere. 

As a gut health dietitian, I think we need to talk more about it, especially because after working with clients one-on-one for over a decade, I saw that people either A) aren’t getting the advice they need to improve symptoms and reduce risk of flares or B) getting bad advice, like not eating nuts or skipping fiber entirely. Gut health nutrition is filled with misinformation, and I’m here to bust it.

FYI: this post was originally intended as part of my gut health book Good For Your Gut, but it got cut because the book was running long. So I have updated it to share here with you…use this handy table of contents to jump ahead to the information you need.

What is diverticular disease (diverticulosis)?

Diverticular disease is the development of outpouchings (called diverticula) in the intestine; they’re essentially tiny hernias in the colon wall. It is thought that the gut wall can pouch when pressure is consistently too high – yep, I’m looking at you, low fibre, slow motility and irregular elimination AKA constipation. Diverticuli are common in parts of the colon – like the sigmoid colon – that are less stretchy and a bit weaker. But we’re still not sure if we know all we need to know. That’s gut health for you!

People can actually have diverticular disease without ever having any symptoms or negative health outcomes. However, if those pouches become infected, you’ve got diverticulitis and it can be intense. Others develop chronic symptoms that overlap with irritable bowel syndrome a little bit, called symptomatic uncomplicated diverticular disease, or SUDD.

What is diverticulitis? 

Diverticulitis is when your diverticuli get infected and inflamed. A flare of diverticulitis can range from mild to so bad it can land you in emergency…so don’t wait to go to your doc if you think something is up with your gut. When it happens, micro-perforations allow the translocation of gut bacteria (AKA actual leaky gut) across the gut wall and spark an infection response. And a flare may be the first time you learn that you have diverticula, unless they’ve been spotted in a colonoscopy beforehand. 

Symptoms of diverticulitis include:

  • changes in bowel habits
  • abdominal pain, typically on the left side, may be severe
  • nausea and vomiting
  • abdominal tenderness

How to eat with diverticular disease

What is the best diet for diverticulitis? I hate to break it to you, but there is a serious lack of gold-standard nutritional information to care for diverticular disease and diverticulitis. And what you eat when you are in a diverticulitis flare versus what you eat to prevent diverticulitis are two entirely different beasts

So some of this information comes from the scientific literature, and some of it is based on over 15 years of practice-based experience as we care for people with diverticular disease.

First things first: we have got to stop telling people that they cannot eat nuts and seeds with diverticular disease!! 

It’s my biggest pet peeve, because it’s pretty common that folks with diverticular disease are told either to avoid nuts, seeds and corn – or eat a completely low fibre diet. But it’s not the smart bet. And it’s not evidence-based

Nuts and seeds are incredibly healthy and full of fibre that will help keep your gut in tip top shape to help you avoid a flare; in one trial, nuts and popcorn were associated with decreased risk of diverticulitis

If that advice makes you nervous, I can offer two things:

  1. Be sure to chew your food exceedingly well. It should be mush before you swallow. The more you chew, the better you break down cell walls so they are fully digested. 
  2. There are a couple of seeds that are really hard to chew: namely tiny ones like sesame, flax and chia seeds. They are so tiny that it is hard to get at them – but you don’t have to avoid them. Just eat them ground! You’ll harness more of their nutrition that way too.

In terms of dietary pattern, we know that the standard high sugar, high fat, low fibre diet is associated with increased risk of diverticulitis – as is high red meat intake. If you eat red meat, I recommend not eating it more than once a week for overall health.

High fiber diet for diverticulosis

Not surprisingly, high fibre diets appear to have a protective effect. If you have diverticular disease and are trying to stay symptom-free and healthy, it’s all about high fibre plant foods like the plant-based recipes I share here, and the Protect recipes in Good For Your Gut.

High fibre foods include legumes like lentils, whole grains like wheat berries, vegetables like broccoli, fruits like berries, as well as nuts and seeds. If you’re wanting to start with a gentle fibre, you can try taking psyllium as it is usually well tolerated.

It’s really important to slowly work up your intake of high fibre foods, perhaps 5 grams of fibre at a time: you can’t go from low fibre to high fibre overnight! You have to build up your tolerance to fibre, kind of like you have to work your way up from lifting a 3 pound weight to a 20 pound weight.

You also need to drink a TON of water as you increase your fibre. Fibre needs water to do its job properly. Ignore this advice and fibre can make you feel ten times worse.

If you’re not feeling so great, particularly if you have IBS-like symptoms, you’ll need to customize your nutrition, ideally with a registered dietitian. Perhaps there are individual foods that cause symptoms – or you notice that if you eat in a certain way, things get worse. A low FODMAP approach may help for a short term as you are trying to get symptoms under control – I have plenty of low FODMAP recipes here and in the book!

What to eat in a diverticulitis flare

With diverticular disease, we eat to maintain gut health and reduce risk of diverticulitis. But if you find yourself in a flare, all bets are off. You eat A) what you can keep down and B) what will reduce the pain. 

In a flare, the most important thing you can do is to follow your doctor or clinical dietitian’s advice. Like sure, read this blog, but talk to them before doing/starting anything. 

Your practitioner may have you on a clear fluid- or liquid-only diet to help reduce pain and inflammation for a few days. When our clients are transitioning from these kind of regimes, we start first with lower fibre (and perhaps low FODMAP) foods such as white pasta, tofu and bananas. 

Then, we work on regaining tolerance with a lot of blended and easily digestible options that such as oatmeal, smoothies, juices, well-cooked vegetables and blended vegetable soups. Finally, we slowly work up to a high fibre diet as tolerated for long term care.

You have to listen to your body here – if it hurts, don’t eat it.

Supplements for diverticular disease

There are really only two supplements are worth talking about, because the evidence base is scrawny at best. The first is probiotics: one review suggested a positive trend for improvement but it’s a total crapshoot on whether one of the products you find on the shelf will help. The American Gastroenterological Association recommends not taking them and I don’t see any reason for probiotics to be a first line of defense here.

A clearer picture emerges for vitamin D as there is an association between low vitamin D levels and diverticulitis – but association doesn’t always mean one causes the other. However, because we all need vitamin D for general health anyways, I strongly recommend taking it daily. Ideally, you would have your doctor test your levels and customize a dose for you. In the absence of that guidance, taking 1000 IU of vitamin D3 in the brightest six months of the year and 2000IU of vitamin D3 in the darker months is a safe dose for adults.

Nerd Stuff: The Gut-Brain Connection in Diverticular Disease

Diverticular disease and diverticulitis have long been thought of as a rather cut and dried physical issue but honestly, there is stuff we don’t understand about how diverticuli even form. We don’t have a lot of information about gut-brain involvement in the development of diverticuli; however, in SUDD or post to diverticulitis states there are some interesting findings to chew on.

After an episode of diverticulitis, there is a significant risk of IBS-like symptoms developing – in one study, IBS was five times higher in those with previous diverticulitis than those without. I’ve seen this in our private practice: the amount of food sensitivity reactions, pain and erratic bowel movements can be very difficult to manage.

In the same study, mood disorders were twice as likely in those with previous diverticulitis so it begs the question, what’s going on with the brain-gut connection here?

Chronic low grade inflammatory states are associated with diverticulitis (but not necessarily diverticular disease) in the research and the enteric nervous system, with its effect on the musculature of the colon and motility, may play a role here. In SUDD, it is thought that visceral hypersensitivity may contribute to pain sensations – just like in IBS. Since anti-inflammatory medications such as NSAIDs can increase risk of diverticular disease, the inflammatory connection makes sense too. 

In the emerging evidence on the gut microbiota, there a lot of conflicting results. Some trials suggest that asymptomatic diverticular disease is not associated with changes in the gut microbiome; however, diverticulitis might be. So at this point, it looks like diverticular disease is a bit more physical in nature; however, the gut-brain-microbiome axis might be involved in turning those diverticuli into diverticulitis or SUDD. Time will tell!


  1. Strate, Lisa L, and Arden M Morris. “Epidemiology, Pathophysiology, and Treatment of Diverticulitis.” Gastroenterology vol. 156,5 (2019): 1282-1298.e1. doi:10.1053/j.gastro.2018.12.033
  2. Rezapour, Mona et al. “Diverticular Disease: An Update on Pathogenesis and Management.” Gut and liver vol. 12,2 (2018): 125-132. doi:10.5009/gnl16552
  3. McSweeney, William, and Havish Srinath. “Diverticular disease practice points.” Australian Family Physician 46.11 (2017): 829.
  4. Ticinesi, Andrea, et al. “Diverticular Disease: a Gut Microbiota Perspective.” Journal of Gastrointestinal & Liver Diseases28.3 (2019).
  5. Lahner, Edith, et al. “Probiotics in the Treatment of Diverticular Disease. A Systematic.” J Gastrointestin Liver Dis 25.1 (2016): 79-86.
  6. Tursi, Antonio, and Walter Elisei. “Role of Inflammation in the Pathogenesis of Diverticular Disease.” Mediators of inflammation vol. 2019 8328490. 14 Mar. 2019, doi:10.1155/2019/8328490

Note: these were my original references for this text. Any new references have been hyperlinked!