IBD, growth and weight: What parents should know

Is your child’s weight changing, or are you worried they aren’t growing as expected? 

Growth and weight are important parts of looking after children with IBD — but there is no single “right” weight for a child with Crohn’s disease or ulcerative colitis.

Children grow at different rates, and one measurement on its own rarely tells the whole story. Your child’s healthcare team will usually look at their growth pattern over time, along with their symptoms, nutrition, puberty and how well their IBD is controlled.

🌱 Why does IBD affect growth and weight?

Active IBD can make it harder for some children to maintain healthy growth and weight.

This can happen for several reasons, including:

• reduced appetite during an IBD flare

• tummy pain, nausea or diarrhoea making eating difficult

• increased nutritional needs when inflammation is active

• nutrients being lost through diarrhoea or bleeding

• difficulty absorbing nutrients, particularly with some forms of Crohn’s disease

• avoiding foods because eating has become associated with pain or urgency

• side effects from some medications

• ongoing inflammation affecting the body’s normal growth processes.

Not every child with IBD will experience growth or weight problems. Some children continue to grow normally throughout their illness.

📈 What does healthy growth look like?

For children, growth is about much more than weight.

Your healthcare team may monitor:

• weight

• height or length

• growth velocity — how quickly your child is growing

• BMI, when appropriate

• growth pattern over time

• puberty and development

• appetite and food intake

• nutritional deficiencies

• IBD activity and inflammation.

Rather than focusing on one number, doctors usually look at the pattern over time.

For example, a child who has always been smaller than their peers but continues to grow steadily may be very different from a child whose weight or height has recently stopped progressing.

⚖️ What if my child is losing weight?

Unintentional weight loss can happen during an IBD flare, particularly if your child is eating less or experiencing significant diarrhoea, pain or other symptoms.

If you notice that your child is:

• losing weight without trying

• eating much less than usual

• struggling to maintain their usual intake

• becoming increasingly tired or weak

• having frequent diarrhoea or vomiting

• experiencing ongoing abdominal pain

• falling away from their usual growth pattern

let their IBD team know.

Weight loss doesn’t automatically mean your child is having an IBD flare, but it is important to look at the possible causes.

Your child’s team may consider symptoms, blood tests, faecal calprotectin, nutritional intake and other investigations to work out what is happening.

⚖️ What if my child is gaining weight?

Weight gain can also be part of childhood and puberty, and it isn’t necessarily a sign that something is wrong.

Some children with IBD may gain weight quickly after inflammation is brought under control and their appetite improves.

Certain treatments can also affect appetite, fluid balance or weight. For example, corticosteroids can increase appetite and may cause changes in body composition while they are being used.

If you are concerned about your child’s weight, talk with their healthcare team rather than putting them on a restrictive diet.

Children with IBD still need enough energy and nutrients to support growth, development and healing.

📏 Growth can be affected even when weight looks okay

It’s possible for a child’s weight to appear relatively stable while their height growth slows.

This is one reason your child’s healthcare team may track both height and weight over time.

Slower height growth can sometimes be associated with ongoing inflammation, inadequate nutrition or delayed puberty.

If your child isn’t growing as expected, the IBD team may want to investigate whether inflammation is adequately controlled and whether they are getting enough energy, protein and essential nutrients.

🧑‍🦱 What about puberty?

IBD can sometimes affect the timing of puberty, particularly when inflammation has been active for a long time or nutritional needs aren’t being met.

Your child’s healthcare team may monitor puberty alongside their growth.

If you’re concerned that puberty seems delayed, your child’s height isn’t progressing as expected, or their development seems different from their peers, mention it at an appointment.

There can be many reasons for differences in puberty timing, so it doesn’t necessarily mean that IBD is the cause.

🥦 Could nutritional deficiencies affect growth?

Children with IBD can be at risk of nutritional deficiencies, particularly when disease is active or food intake is limited.

Depending on your child’s situation, their healthcare team may monitor nutrients such as:

• iron and ferritin

• vitamin D

• vitamin B12

• folate

• calcium

• zinc

• other vitamins and minerals where appropriate.

Iron deficiency can be particularly important because it may contribute to tiredness and anaemia.

Your child’s IBD team or dietitian can advise whether blood tests or supplements are appropriate.

🍽️ Should I try to make my child gain weight?

If your child is struggling to maintain weight, it can be tempting to encourage them to eat as much as possible.

But simply adding more food isn’t always the answer.

The reason for poor weight gain needs to be understood first.

For example, if your child has active intestinal inflammation, significant pain or ongoing diarrhoea, increasing food alone may not solve the underlying problem.

Your IBD team may recommend:

• increasing energy and protein in meals

• smaller, more frequent meals

• high-energy snacks

• nutritional drinks or supplements

• specific nutrition strategies

• treatment to control active IBD

• referral to a paediatric IBD dietitian.

Some children with Crohn’s disease may also be offered exclusive enteral nutrition (EEN) or another specialised nutritional approach as part of their IBD treatment. These treatments should only be undertaken with guidance from the child’s IBD team and dietitian.

🥗 Should I put my child on a diet if they’re gaining too much weight?

This is something to discuss with your child’s healthcare team before making significant changes to their diet.

Restrictive diets can make it harder for children with IBD to get the energy, protein, vitamins and minerals they need.

Instead of focusing only on the number on the scales, the team may look at your child’s overall growth pattern, nutrition, activity, puberty and IBD activity.

A paediatric IBD dietitian can help your family make changes that support both healthy growth and good nutrition.

🏠 What can I do at home?

You don’t need to weigh your child every day.

In fact, frequent weighing can sometimes create unnecessary worry, particularly for older children and teenagers.

Instead:

🔎 Keep an eye on the bigger picture

Notice changes in:

• appetite

• energy levels

• eating patterns

• bowel habits

• abdominal pain

• weight or clothing fit

• height and growth

• activity levels

• mood and wellbeing.

❤️ Keep meals positive

Try to avoid making weight the focus of family meals.

Children with IBD can already develop anxiety around food, particularly if eating has previously caused pain or urgency.

Aim to make food as relaxed and enjoyable as possible.

🚫 Don’t unnecessarily restrict foods

Removing large numbers of foods without professional guidance can increase the risk of nutritional deficiencies.

If you think particular foods are causing symptoms, keep a simple food and symptom record and discuss the pattern with your child’s IBD team or dietitian.

💊 Follow the treatment plan

Good nutrition is important, but food cannot replace treatment for active intestinal inflammation.

Continue your child’s prescribed IBD treatment and speak with their healthcare team if you think their symptoms are returning.

📞 When should I speak with the IBD team?

Contact your child’s IBD team if you notice:

• unexplained weight loss

• poor weight gain

• a noticeable change in appetite

• slowing or stopping of height growth

• ongoing diarrhoea

• persistent abdominal pain

• increasing fatigue

• vomiting

• blood in the stool

• difficulty eating because of pain or fear

• significant food restriction

• concerns about delayed puberty

• concerns about your child’s relationship with food or body image.

Your child’s team can help work out whether the change is related to IBD activity, nutrition, medication, another medical issue or normal childhood growth.

🌱 Remember: growth is a journey

Every child has their own growth pattern.

With IBD, your child’s healthcare team will usually look at growth, weight, nutrition, puberty and inflammation together, rather than relying on a single measurement.

If your child’s weight or growth changes, don’t panic — but don’t ignore it either. Let the IBD team know so they can look at the bigger picture and decide whether anything needs to be investigated.

With appropriate IBD treatment, nutrition support and regular monitoring, many children with Crohn’s disease or ulcerative colitis can continue to grow, develop and take part in everyday life.

💛 You don’t have to work out your child’s growth or nutrition needs on your own. Your IBD team and paediatric IBD dietitian are there to help.