Why does Crohn's disease cause unintentional weight loss?

Crohn's disease inflames parts of the digestive tract. During active inflammation, the body may need more energy while nausea, abdominal pain, diarrhoea, or tiredness can make meals less appealing. Inflammation in the small bowel may also limit absorption of nutrients. Unintentional Weight Loss is a common presentation of Crohn's Disease, but weight change has many possible causes and needs individual assessment.

A changing appetite, looser stools, food avoidance, or fatigue can offer useful clues about what is driving the weight loss. Keeping a brief record of meals, symptoms, bowel changes, and weight can help a clinician understand the pattern.

Contact the clinician managing your Crohn's disease if weight is falling or eating has become difficult. They may review whether inflammation is controlled, discuss blood tests or stool testing, and arrange dietetic support. Choose smaller, more frequent meals if large meals are difficult, drink regularly, and avoid restricting foods unless a clinician has identified a reason.

Seek urgent medical care for severe or worsening abdominal pain, repeated vomiting, a swollen abdomen, black or bloody stools, fainting, confusion, or signs of dehydration such as very little urine. These symptoms need prompt assessment whether or not weight loss is present.

Ask whether your current symptoms suggest active bowel inflammation, whether you need nutritional blood tests, and which foods are realistic to tolerate while symptoms settle. It can also help to ask when to report further weight loss or diarrhoea.