Yes, Crohn’s disease can sometimes lead to weight gain. But that link isn’t as widely discussed as the condition’s connection with weight loss, according to Brigid Boland, MD, a gastroenterologist, assistant professor of medicine at the University of California San Diego, and a spokesperson for the American Gastroenterological Association.
“From what we currently know, Crohn’s disease itself does not cause weight gain; however, there are likely different indirect ways in which weight gain could occur,” Dr. Boland says.
The most common factors tied to weight gain in people with Crohn’s disease include:
Medications and Their Side Effects
Corticosteroids are often prescribed as a short-term solution to manage inflammation during a Crohn’s flare-up. They’re also a well-known cause of weight gain, says Alan Moss, MD, the chief scientific officer at the Crohn’s & Colitis Foundation and a professor of gastroenterology at Boston University in Massachusetts.
“Steroids … can cause weight gain, and that’s typical visceral weight gain around the [abs] with changes in fat distribution, and also around the face,” Dr. Moss says. He notes that long-term use can also affect blood sugar and bone health. That’s why gastroenterologists typically aim to keep people with Crohn’s on steroids for no longer than about four weeks to manage a flare.
Boland says that long-term steroid use can decrease metabolism, increase appetite, and cause fluid retention — all of which can also lead to weight gain.
Moss says other, newer medications, such as biologics, don’t cause weight gain. People who do gain weight after starting biologics are typically recovering lost weight due to prior malnutrition or active disease.
Diet Changes and Food Aversions
Being unable to stick to a balanced diet is another major hurdle that can trigger weight gain in people with Crohn’s, Moss says.
During a flare, it’s easy to shift toward eating foods that are easier to tolerate but more likely to cause weight gain, such as ultra-processed foods and refined carbohydrates. These habits can stick, even after you achieve remission.
Some people tend to avoid eating healthy foods that cause symptoms during a flare, such as high-fiber foods and low-fat dairy. During remission, they can work these foods back into their diets, but they often don’t because they’re fearful of another flare-up.
“No one ever tells them to reassess what [they’re] eating and get back to a more balanced diet,” Moss says.
Fatigue and Inactivity
When you’re dealing with Crohn’s symptoms, you may not have energy for a workout. But inactivity plus a change in diet can lead to gradual weight gain.
“If the combination of feeling unwell, having low energy, and then eating highly processed foods [comes together], it’s a bad mix that will lead to excess weight gain,” Moss says.
Stress and Emotional Eating
The stress of living with the illness can sometimes lead to changes in eating patterns, including overeating or what seems like emotional eating.
In other cases, some people might overeat once a flare-up has ended and it feels safe to eat again, says Chelsea Cross, RD, who’s also a personal trainer in Kitchener, Ontario, Canada. Cross has Crohn’s disease and works with clients who have IBD.
“Once clients start to heal, [and] medications make them feel better, sometimes what happens is overindulgence in hyper-caloric foods, as many feel super restricted when they’re ill,” she says.
Returned Appetite in Remission
After successful treatment with medication or surgery that leads to remission, appetite may return quickly — and weight can rebound faster than expected.
After you and your healthcare team settle on a treatment plan that works, you may see weight gain — an indication that you’re on the right track. “Weight gain can be positive … medication is reducing inflammation, allowing for greater [nutrient] absorption, and so the person is getting healthier,” Cross says.
