The most effective way to avoid diverticulitis is eating a high-fiber diet, staying physically active, and maintaining a healthy weight. These three factors alone account for a large share of preventable risk. About 50% of diverticulitis risk is genetic, according to the American Gastroenterological Association, but the other half is shaped by habits you can change.
Eat More Fiber (and How Much Matters)
Fiber is the single most studied dietary factor in diverticulitis prevention, and the evidence is clear: more fiber means less risk, in a dose-dependent way. A large meta-analysis of prospective studies found that people eating 30 grams of fiber per day had a 41% lower risk of diverticular disease compared to those eating only about 7.5 grams. At 40 grams per day, the reduction reached 58%.
Most adults in the U.S. eat around 15 grams of fiber daily, roughly half the recommended amount. Closing that gap doesn’t require a dramatic overhaul. Adding a cup of lentils (about 15 grams), a pear (6 grams), or a bowl of oatmeal (4 grams) to your existing meals makes a real difference over time. If you’re not used to eating much fiber, increase gradually over a few weeks to avoid bloating and gas. Your gut bacteria need time to adjust.
Drink plenty of water as you increase your fiber intake. Fiber absorbs water as it moves through your digestive system, and without enough fluid, it can actually slow things down rather than help.
Cut Back on Red Meat
A large prospective study following men over decades found that those who ate the most red meat had a 58% higher risk of diverticulitis compared to those who ate the least. Each additional daily serving of red meat raised the risk by about 18%. The association held after adjusting for fiber intake, exercise, and other lifestyle factors, suggesting red meat contributes independently to risk.
You don’t need to eliminate red meat entirely. Replacing even one or two servings per week with poultry, fish, or plant-based protein shifts your risk profile in the right direction.
Stay Active, Especially With Vigorous Exercise
Regular physical activity reduces diverticulitis risk, and intensity matters. Men who engaged in roughly three hours per week of vigorous activity (like running) had a 34% lower risk of diverticulitis and a 39% lower risk of diverticular bleeding compared to men who didn’t exercise vigorously. The benefit comes on top of whatever protection diet provides.
Vigorous exercise stimulates the colon’s natural contractions, helping move waste through more efficiently. It also reduces systemic inflammation, which plays a role in turning harmless diverticula (small pouches in the colon wall) into inflamed, painful ones. If running isn’t your thing, cycling, swimming laps, or brisk hiking all count as vigorous activity.
Maintain a Healthy Weight
Carrying excess weight, particularly around the midsection, raises diverticulitis risk substantially. Men with a BMI of 30 or higher had a 78% greater risk of diverticulitis compared to those with a BMI under 21. Waist circumference told a similar story: men with a waist over 40 inches had a 56% higher risk than those with waists under 34 inches.
Abdominal fat is especially relevant because it produces inflammatory compounds that affect the colon directly. Even modest weight loss, if you’re currently overweight, can reduce that inflammatory burden.
Be Cautious With Common Pain Relievers
Regular use of over-the-counter anti-inflammatory pain relievers is an overlooked risk factor. Taking ibuprofen, naproxen, or similar medications two or more times per week raised diverticulitis risk by 72% in one large study. Regular aspirin use increased it by 25%. Using both together pushed the risk up 65% for diverticulitis and doubled the risk of diverticular bleeding.
These medications can weaken the protective lining of the colon, making existing diverticula more vulnerable to inflammation and perforation. The AGA specifically recommends that people with a history of diverticulitis avoid regular NSAID use (twice a week or more), with an exception for low-dose aspirin prescribed for heart disease prevention. If you rely on these drugs for chronic pain, it’s worth exploring alternatives like acetaminophen, which doesn’t carry the same colon-related risks.
Stop Smoking
Current smokers have about a 46% higher risk of developing diverticular disease compared to nonsmokers. Smoking impairs blood flow to the colon wall and promotes chronic inflammation, both of which make diverticula more likely to become infected. Quitting reduces this risk over time.
Keep Your Vitamin D Levels Up
Lower vitamin D levels are consistently linked to higher rates of diverticulitis, and the relationship is striking. People in the highest fifth of vitamin D blood levels had roughly half the risk of being hospitalized for diverticulitis compared to those in the lowest fifth. The sharpest drop in risk occurred as levels rose from low to moderate, around 25 to 30 nanograms per milliliter, with smaller additional benefits above that range.
People who were hospitalized for diverticulitis had average vitamin D levels of about 25 ng/mL, while those with uncomplicated, symptom-free diverticula averaged 29 ng/mL. The most severe cases, those requiring emergency surgery, averaged just 23 ng/mL. Getting regular sun exposure, eating vitamin D-rich foods like fatty fish and fortified dairy, or taking a supplement if you’re deficient are all reasonable strategies.
Ignore the Nuts and Seeds Myth
For decades, people with diverticula were told to avoid nuts, seeds, popcorn, and foods with small particles like strawberries and sesame seeds. The theory was that these tiny pieces could lodge inside a diverticulum and trigger inflammation. There is no evidence this is true. The Mayo Clinic states plainly that there’s no proof these foods cause diverticulitis, and some of them (particularly nuts and seeds) are excellent sources of fiber that may actually be protective.
If you’ve been avoiding these foods out of caution, you can safely add them back into your diet.
Putting It All Together
The AGA’s prevention recommendations boil down to five things: eat a high-quality, fiber-rich diet, keep your BMI in a normal range, exercise regularly, don’t smoke, and avoid frequent NSAID use. Each of these factors independently reduces risk, and they compound when combined. Since about half of diverticulitis risk is genetic, some people will develop it regardless of lifestyle. But for the modifiable half, these changes represent the strongest available protection.