If you have ulcerative colitis (UC), you know the hallmark symptoms: persistent and frequent diarrhea, nausea, and stomach cramping and pain. But the effects of this type of inflammatory bowel disease (IBD) can have far-reaching effects on your health. 

In particular, weight loss and suppressed appetite are often a concern for those with UC. Certain symptoms like pain and nausea can prevent people with UC from eating properly, and the ulcers and diarrhea that result from the disease, along with medications used to manage them, can make it harder to absorb proper nutrients from food, says John Betteridge, M.D., an ulcerative colitis specialist at US Digestive Health, a gastroenterology practice based in Exton, PA.

Worried about ulcerative colitis-related weight loss, or wondering how to gain weight with colitis? Let’s take a closer look at what’s going on in your body with UC—and how experts say to handle it. 

Why Ulcerative Colitis Changes Your Appetite

Any time you’re sick, it’s possible for your appetite to take a hit as your immune system releases inflammatory proteins to combat the infection, which can also impact your appetite. But unlike, say, the flu, where your appetite will rebound when you recover, ulcerative colitis is a chronic condition—and so appetite changes can persist, says Dr. Betteridge. 

Plus, the very nature of ulcerative colitis makes changes in appetite more likely. “With UC, lack of appetite is much more common because these patients have inflamed or ‘sick’ colons that don’t function well,” says Dr. Betteridge. “There is a feedback loop to the brain and other digestive organs triggering a change in the hormonal and nervous system controls over hunger and satiety.” 

IBD, and the inflammation it causes, is thought to impact two hormones: leptin (which suppresses appetite) and ghrelin (which tells your brain when you’re hungry), reports the Cleveland Clinic. And research on nutrition and irritable bowel syndrome finds that increased leptin, in particular, is a major cause of reduced food intake in IBD patients. That means that ulcerative colitis not only affects a person’s ability to digest or desire food, but also their body’s ability to experience normal hunger cues.

Problems Caused by Loss of Appetite With UC

A consistent lack of appetite or avoidance of food can have a significant impact on someone’s weight and overall health. For example, not eating enough can contribute to nutritional deficiencies, or too-low levels of vital nutrients, says Kuanteya Reddy, M.D., the medical director of gastroenterology at Redlands Community Hospital in California. 

“Nutritional deficiencies are more common if you have significant ongoing inflammation. Additionally, anemia may result from blood loss and chronic ongoing inflammation,” says Dr. Reddy. “You may need to take extra iron, vitamins and other supplements to keep up with ongoing losses.” Your doctor may monitor your iron, vitamin, and nutrient levels with regular blood tests and prescribe supplements if needed, he adds.

Not eating enough could lead to other symptoms as well, like fatigue and changes to your skin, hair, and nails (like thinning hair, brittle nails, and dry, patchy skin), according to the Mayo Clinic. If left unaddressed, it’s also not uncommon for moodiness, irritability, or difficulty concentrating on normal, daily tasks or conversations to occur.

Appetite Changes and Weight With Ulcerative Colitis

Not surprisingly, a decrease in appetite is associated with weight loss—which can be a major issue in people with UC. In one often-cited study on IBD and weight loss, researchers tracked the body mass index (BMI) of 494 people with either Crohn’s disease or UC. Overall, 51% of people with ulcerative colitis experienced significant weight loss leading up to their diagnosis.

While many people think weight loss is chiefly due to poor absorption of nutrients, Dr. Betteridge says this is only a small factor in UC-related weight loss. More pressing, he says, is how UC lowers appetite, and how symptoms often cause food-avoidant behaviors in people with IBD like ulcerative colitis and Crohn’s disease.

When you have severe UC—i.e., you’re dealing with stomach pain and diarrhea daily—you often just don’t feel like eating, especially when every meal or snack triggers more uncomfortable symptoms. “Often patients with active UC symptoms avoid eating to try and control the symptoms of diarrhea, pain, and urgency,” says Dr. Betteridge. “Also, their overactive immune system has their metabolism in overdrive, and their immune cells are using calories and energy to generate these inappropriate immune responses.” 

Ulcerative Colitis Medications and Weight

Ideally, your ulcerative colitis treatment will lead to an improvement in symptoms and a reduction in inflammation which can make it easier to eat a wider range of foods, get proper nutrients, and gain weight.

Unfortunately, though, certain medications available can lead to a decreased appetite in some people. For example, sulfasalazine, mesalamine, and olsalazine all have a loss of appetite or decreased appetite as a potential side effect. (On the other hand, steroids and biologics may both lead to weight gain.) 

How to Deal With a Loss of Appetite

For many people with ulcerative colitis, managing weight, appetite, and UC symptoms is a challenge. But the best way to get enough nutrients and avoid weight loss is to work with your doctor to get your ulcerative colitis under control, often through medication. A combination of medication and diet can help bring your UC into remission (when the colon is no longer inflamed), allowing for reduced symptoms, a better appetite, and less abdominal pain—meaning not only is it easier to eat comfortably but also easier to absorb nutrients. 

Meanwhile, on your journey to controlling your UC, if you’re struggling with loss of appetite and weight loss, these tips from Dr. Betteridge may help:

• Eat small, frequent meals (rather than three big meals a day) to up your calorie intake.
• Snack on high-quality, IBD-friendly food sources like eggs, baked chicken, and fish that are easy to digest, low in fat, and rich in protein.
• Talk to your doctor about nutritional supplements, like vitamin-rich liquid diet supplements. 

If you experience food avoidance, it might also be helpful to ask a partner or family member for help. For example, ask to eat or prep meals together, or for them to help remind you when it’s time for a snack.

What to Eat During UC Flares

It’s also important to know that your ulcerative colitis diet may need to change during flare ups. Dr. Betteridge recommends a low residue diet with frequent meals during flares. Low residue diets describe low-fiber meals that usually exclude dairy, certain types of cramp-inducing carbohydrates, and seeded fruits. Following this type of plan can help manage UC flares by limiting the amount of irritating “residue”—like undigested fiber and other foods—in the digestive system. 

And while tolerance of certain foods can vary from person to person, Dr. Reddy says, “Some people feel better by avoiding the intake of dairy products, like yogurt and cheese.” However, you should always speak with your doctor before altering or restricting your diet, he cautions, in order to make sure you’re getting the nutrition your body needs. (These ulcerative colitis-friendly recipes are high in nutrients and easy on the gut.)

Overall, people with UC should work with their doctors to develop an individualized nutritional plan, and to determine if added supplements and vitamins are needed.

The Bottom Line

There is definitely a learning curve when it comes to handling appetite changes that affect your diet and weight with UC. But keeping an eye on your nutritional intake, adjusting your diet to minimize flares, and working with your doctor to find the right medication can help you maintain your weight and health now and in the years to come.

Notes: This article was originally published May 9, 2023 and most recently updated May 11, 2023.

By Sara Youngblood Gregory 

Medical Reviewer: Mona Rezapour, M.D.