Crohn’s Disease And Weight

What is Crohn’s disease? 

Crohn’s disease is a lifelong condition that affects the digestive system, where parts of the gastrointestinal tract (GI) become inflamed.1,2 It is a chronic disease and belongs to a group of conditions called inflammatory bowel diseases (IBD).1

The inflammation can affect any area of the GI tract, but it most often affects where the small bowel meets the colon.1 In some cases the entire thickness of the bowel wall is inflamed, while in other cases the inflammation leaves some areas unaffected, and shows up in a patchy pattern along the GI.1


The main symptoms of Crohn’s disease are:3

  • Stomach aches and cramps - often in the lower right part of the stomach
  • Diarrhoea and constipation 
  • Bloating
  • Blood in your stool 
  • Fatigue
  • Weight loss

Someone with Crohn’s disease might not have all of the above symptoms. Other symptoms that might be experienced include:3,4

  • Nausea and vomiting
  • Pains in the joints - this is the main symptom that is felt outside the gut
  • A high temperature
  • Mouth ulcers
  • Sore and red eyes
  • Swollen, painful skin - usually affecting the leg
  • Dehydration

When Crohn’s is not treated, the symptoms flare-up and might be present for weeks or even months. The flare-up or relapse is followed by phases of remission, where the symptoms temporarily disappear.3

Crohn’s disease can make keeping a stable weight difficult

Weight loss is one of the most common symptoms of IBDs.5 There are many reasons why people with Crohn’s lose weight, such as:5,6

  • Poor appetite and nausea
  • Nutrient loss due to diarrhoea 
  • Increased metabolism due to bodily processes fighting the disease
  • Intestinal bleeding which causes a loss of nutrients
  • Malabsorption - difficulty in the digestion or absorption of nutrients from food
  • Food aversions - a strong dislike towards certain foods
  • Inflammation which makes it harder to absorb the nutrients from food
  • Less pleasure from eating

Anti-inflammatory medications may lead to weight gain 

Prednisone, a steroid-based drug, causes weight gain due to the following reasons:8

  • Increased fluid retention - your body holds on to sodium and loses potassium which results in swelling and bloating
  • Increased appetite - causes you to eat more
  • Changes in fat distribution - the fat will be deposited in areas such as the face, back of the neck, and belly

 Some other reasons why people living with Crohn’s might gain weight include:7

  • Challenges with healthier food options - some healthy foods, such as fruits and vegetables, contain a lot of insoluble fibre. Whilst these foods promote health in most cases, for people with Chron’s, they can cause flare-ups and contribute to residue in the stomach. Doctors generally recommend a low-residue diet which lowers the number of healthy food choices.
  • Exercise can be challenging for Crohn’s patients - some symptoms, such as fatigue, joint pains, bloating or just going to the bathroom a lot, make it hard to exercise regularly. 

Obesity is a risk factor for Crohn’s disease 

Recent studies show that obesity impacts the gut in several ways. It modulates the immune response, affects intestinal permeability, and changes the gut microbiome.10 Obesity also contributes to gut inflammation by accelerating the accumulation of pro-inflammatory intestinal macrophages.9 They play a critical role in the health of the intestines. Through such pathways, obesity contributes to the emergence of IBDs and Crohn’s disease among them.9,10 Studies have confirmed that obesity is associated with an increased risk of Crohn’s disease.10


Crohn’s is a chronic gut disease for which we currently have no cure. The symptoms persist for weeks or months and are followed by a remission phase. Very often, people living with Crohn’s struggle with maintaining a healthy weight; they can be both underweight or overweight. Frequent diarrhoea, bloating, and lack of appetite contribute to weight loss, while the side effects of medications cause weight gain. Recent studies show that obesity is a significant contributor to the development of Crohn’s due to its inflammatory effects on the gut.


  1. Crohn's & Colitis Foundation. What Is Crohn’s Disease? | Crohn’s & Colitis Foundation [Internet]. Crohn’s & Colitis Foundation. 2019.
  2. NHS Choices. Overview - Crohn’s disease [Internet]. NHS. 2019.
  3. NHS Choices. Symptoms - Crohn’s disease [Internet]. NHS. 2019.
  4. Managing symptoms of Crohn’s Disease, Ulcerative Colitis or Microscopic Colitis [Internet].
  5. December 1 ET, 2015. Loss of Appetite and Weight Loss | UlcerativeColitis [Internet].
  6. NIDDK. Crohn’s Disease | NIDDK [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases. 2019.
  7. Can Ulcerative Colitis Lead to Weight Gain? [Internet]. 2019 [cited 2022 Sep 28].
  8. Prednisone [Internet]. Johns Hopkins Vasculitis Center.
  9. Rohm TV, Fuchs R, Müller RL, Keller L, Baumann Z, Bosch AJT, et al. Obesity in Humans Is Characterized by Gut Inflammation as Shown by Pro-Inflammatory Intestinal Macrophage Accumulation. Frontiers in Immunology. 2021 May 12;12.
  10. Chan SSM, Chen Y, Casey K, Olen O, Ludvigsson JF, Carbonnel F, et al. Obesity is Associated With Increased Risk of Crohn’s disease, but not Ulcerative Colitis: A Pooled Analysis of Five Prospective Cohort Studies. Clinical Gastroenterology and Hepatology [Internet]. 2022 May 1 [cited 2022 Aug 10];20(5):1048–58. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
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