- Many healthy foods are feared in ulcerative colitis, but with proper prep, they’re often safe to eat.
- Cooking, blending and portion control can help reduce symptoms from common trigger foods.
- Individual tolerance varies, so working with a health care professional can guide safe choices.
Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that causes inflammation and ulcers in the lining of the colon. This can lead to symptoms such as diarrhea, abdominal pain, urgency, fatigue and unintended weight loss. Because food can sometimes worsen discomfort during flare-ups, many people with UC believe there are “bad” foods they need to avoid to keep symptoms under control—even when those foods are otherwise considered healthy choices.
In reality, many people with UC can tolerate a much wider variety of foods than they expect. “We know that having lots of color, diversity and even fiber in the diet is important for reducing the overall risk of flare-ups and disease activity in IBD,” says registered dietitian Ashley H. Hurst, M.S., RD, LD.
That said, there is no one-size-fits-all approach—trigger foods are highly individual, and what may bother one person may be well tolerated by another. To learn which commonly feared “bad” foods may actually fit into a balanced eating pattern for UC, we spoke with registered dietitians who specialize in digestive disorders.
1. Leafy Greens & Vegetables
Leafy greens and other vegetables are often considered “bad” for UC because of their fiber content, yet experts say they don’t necessarily need to be off-limits. Unless there’s a specific medical reason to avoid certain foods, the American Gastroenterological Association recommends a Mediterranean-style eating pattern for people with IBD—one that emphasizes fruits, vegetables and other minimally processed plant foods.
Research suggests that both the type of fiber and how vegetables are prepared can influence symptom tolerance. Soluble fiber—found in foods like carrots, sweet potatoes, zucchini and squash—tends to be better tolerated than insoluble fiber for many people with UC.
Preparation can also make a difference. Cooking, blending or softening vegetables higher in insoluble fiber—like leafy greens—may make them easier to digest. For example, cooking spinach in soups or casseroles, or blending leafy greens into a smoothie, may improve tolerance, suggests Hurst.
Beyond symptom management, vegetables provide essential vitamins, minerals and beneficial plant compounds. Evidence also suggests that eating a wide variety of plants supports a more diverse gut microbiome, which is linked to better gut health and lower inflammation.
2. Beans & Legumes
While beans and legumes are often avoided during active flare-ups, research and gut-health experts encourage including them during remission, when symptoms are minimal or absent.
“Legumes are a nutrient-dense whole food, and one of the best sources of fiber,” says Avery Zenker, RD. The soluble fiber in beans dissolves in water and forms a gel-like substance in the gut, where bacteria break it down into short-chain fatty acids (SCFAs)—compounds that support the colon’s lining and overall gut health. These by-products may also help reduce inflammation in people with IBD.
Soluble fiber can further support digestion by helping normalize bowel movements, easing both constipation and diarrhea. However, introducing too much fiber at once may cause side effects such as gas and bloating. Starting with small portions and gradually increasing intake can help improve tolerance over time.
“Similar to how when we go to the gym, we aren’t expecting to get stronger in the first week, your gut microbiome is the same way. It takes time, consistency and strategy,” explains Hurst.
3. High-Fiber Grains
Whole grains are often avoided by people with UC because of their fiber content, yet research suggests certain types—particularly those rich in soluble fiber—may support gut health when symptoms are stable.
“Oats may be especially beneficial for UC due to their high content of beta-glucan, a type of soluble fiber,” says Zenker.
In a small clinical study of people with UC in remission, eating oat bran increased levels of butyrate—a key short-chain fatty acid linked to a stronger gut lining—without triggering flare-ups or worsening digestive symptoms. However, longer-term research is needed to determine whether it can improve disease outcomes.
Along with oats, other whole grains like barley and quinoa may also fit into a balanced eating pattern for many people with UC during remission. Starting with smaller portions and choosing well-cooked grains can make them easier to digest while allowing tolerance to build gradually.
4. Nuts & Seeds
Nuts and seeds are core part of the Mediterranean-style eating pattern, which experts increasingly recommend for people with IBD in remission due its focus on whole, plant-based foods and healthy fats. While research on nuts and seeds specifically in UC is limited, they’re included within broader plant-forward dietary patterns that have been linked to improved gut microbiome diversity and markers of gut health in people with the condition.
Zenker notes that options such as flaxseed, chia seeds, hemp seeds and walnuts may be especially beneficial, as they provide omega-3 fatty acids, which have been shown to help reduce inflammation.
For some people with UC, choosing ground seeds, nut butters or finely chopped nuts can make these foods easier to tolerate while still providing nutritional benefits. As with other high-fiber foods, starting with small portions and gradually increasing intake can help improve tolerance over time.
5. Fermented Dairy
Although many people with UC limit dairy because they believe it worsens symptoms, research doesn’t strongly support eliminating it across the board. A systematic review of milk and dairy intake in patients with IBD found no clear evidence that dairy products influence disease activity or progression, especially in those without lactose intolerance.
Fermented dairy products, in particular, may offer potential benefits for gut health in people with UC. “Fermented dairy products like yogurt and kefir may actually be beneficial for some people,” says Zenker.
These foods contain live probiotic cultures and fermentation-derived compounds such as short-chain fatty acids and bioactive peptides that support a more diverse gut microbiome and help maintain a strong intestinal barrier. Together, these components may promote a healthier gut environment and ease digestive discomfort for some individuals with UC. Though, more research is still needed.
To assess personal tolerance, consider starting with small portions and choosing plain, unsweetened varieties, which also align with Mediterranean-style eating patterns that emphasize limiting added sugars.
Our Expert Take
When it comes to ulcerative colitis, there’s no single “right” way to eat, and long-term avoidance of entire food groups isn’t supported by research. Instead, experts emphasize a balanced diet rich in whole, nutrient-dense foods—such as those highlighted in the Mediterranean diet—while paying attention to individual triggers, since tolerance can vary widely from person to person.
Many foods once considered off-limits can often be reintroduced during remission and may even support the gut microbiome and long-term digestive health. Working with a registered dietitian who specializes in digestive disorders can provide individualized guidance and help you expand your diet safely over time, making it easier to move beyond restrictive eating and enjoy a broader range of nourishing foods.
