Weight loss is a typical symptom of the inflammatory bowel diseases of Crohn’s disease and ulcerative colitis. Weight loss is an indication of malnutrition caused by not getting enough calories to meet your needs. There are many reasons why this happens, including:1,2
- Poor appetite
- Food aversions
- Malabsorption
- Increase in the calories your body burns fighting the disease and its complications
- Nutrient losses due to diarrhea or intestinal bleeding
An older study showed that people with Crohn’s disease who had lost weight reported lower levels of hunger and less pleasure from eating than people who had not lost weight.3 The people who lost weight reported that they had eliminated an average of 16 of 52 food items. This restriction resulted in low calorie intake. Interestingly, in this study, many of the foods had been eliminated at the advice of treating physicians.
Currently, there is no general recommendation on which
foods to eliminate.
4 Inflammatory bowel disease (IBD) is different for every person. Too many unnecessary restrictions can make it hard for you to have a balanced and nutritious diet. Instead, you and your health care team should figure out what foods you tolerate best.
What are some reasons for poor appetite?
Appetite loss is reported in about 1 in 5 people with Crohn’s disease and in about 1 in 10 people with ulcerative colitis.5 Unsurprisingly, problems with appetite in people with IBD are worse during flares. For most people, appetite improves during remission. One small study compared hunger between people with active Crohn’s disease, inactive Crohn’s disease, and no Crohn’s disease. The people with active Crohn’s disease reported feeling less hungry than the other 2 groups at baseline and after drinking 500 mL (~2 cups) of water.6
There are many reasons for loss of appetite in IBD. Some people may develop food aversions because they associate eating with pain.7 After a while, you may try to avoid eating in order to avoid pain or unpleasant symptoms. Depression is common among people with IBD and can lead to a loss of appetite.8 Some medications and nutrient deficiencies cause taste changes.7 If your food tastes off, you may be less interested in eating it.
Inflammation and hormone changes probably have a role in poor appetite. IBD changes the levels of hormones such as leptin and ghrelin.2,9 These hormones have a role in making you feel hungry or full. They also seem to be out of balance in people with active IBD.2,9 An increase in inflammatory signals, such as tumor necrosis factor-α (TNF-α) and interleukins, has been linked with poor nutritional status.10 More research is needed to understand how these factors work together.
How common is weight loss?
Weight loss is very common in people with IBD. One study found that as many as 80% of people who are hospitalized for Crohn’s disease lose weight. Outside the hospital, about 20% to 40% of patients also have weight loss. Weight loss is frequently seen in children with IBD, and weight loss is present at the time of diagnosis in 90% of children with IBD.2
How is weight loss evaluated?
It is not possible to fully evaluate a person’s nutritional status from one weight measurement alone.11 It is important that your provider or dietitian tracks your weight over time.
There are many possible ways to evaluate weight loss. For adults, a common way is to evaluate the percentage of weight loss over a certain period of time (Table).12 Your provider or dietitian may also calculate percentage of usual body weight or percentage of ideal body weight. For children, weight and height are tracked on a growth chart. This can help the provider see your child’s pattern of growth. Your child’s provider will identify any changes in the growth pattern.
Table. Severity of Weight Loss
Calculation:
[(Usual body weight – actual body weight) / Usual body weight] x 100% = Percentage of weight loss
| Significant weight loss: |
Severe weight loss: |
| 5% over 1 month |
>5% over 1 month |
| 7.5% over 3 months |
>7.5% over 3 months |
| 10% over 6 months |
>10% over 6 months |
Source: Blackburn GL, et al. JPEN J Parenter Enteral Nutr. 1977;1:11-22.
How is weight loss treated?
Depending on the circumstances, normal foods, tube feeding, or intravenous (IV) nutrition may play a role in treating weight loss. Tube feeding (enteral nutrition) is an effective way to start remission in children with IBD.2 It also is beneficial for some adults. Tube feeding can be done by inserting a thin, hollow tube through your nose into your stomach or small intestine. A nutrient-rich formula flows through the tube. Intravenous nutrition (also called total parenteral nutrition or TPN) is an option when the digestive tract cannot be used.
No single diet of regular foods has been shown to treat IBD. In general, you should aim for a normal, healthy diet as much as possible.11 You can tailor your diet based on the foods that trigger your symptoms. This varies from person to person, and even from one flare to the next.4 You may need to eat differently during a flare than during remission. During remission, most people with IBD have a good nutritional status.2
