Children aged 6-12 are still growing, which means they need the energy (calories) and nutrients that come from a varied and balanced diet. If your child is underweight, they may not be getting enough calories.
If you're concerned that your child is underweight or not growing normally, see your doctor. Low weight can occur for a number of reasons.
This page covers:
How can I tell if my child is underweight?
Your child's diet
How to increase your child's calorie intake
Keep your child active
Monitor your child's progress
As a parent, it can be difficult to tell if your child is underweight.
If you already know your child's height and weight, and want to know if they're a healthy weight for their age, height and sex, you can check using our healthy weight calculator.
If your child is in Year Six (ages 10 and 11), they may have already been weighed and their height measured as part of the National Child Measurement Programme.
In some areas you may be sent the results for your child. In other areas you will have to contact your local authority to find out your child's measurements.
If results show that your child is underweight, consult your doctor, who can talk to you about the possible causes.
If there is a problem with your child's diet, your doctor can give advice that will help bring your child up to a healthy weight, or refer them to a dietitian.
All children need the energy (calories) and nutrients that come from a varied and balanced diet.
If your child is underweight, it may be tempting to fill them up with high-calorie but unhealthy foods, such as sweets, cake, chocolate and sugary and fatty foods and drinks. However, it's important that your child gains weight in a healthy way, and this means eating a balanced diet.
Once your child is five, they should be eating a healthy, low-fat diet like the one recommended for adults. Find out more in What to feed young children .
The government advises that children aged five and over follow the Eatwell Guide. This guide shows the proportions in which different types of foods are needed to have a well-balanced diet:
Try to choose a variety of different foods from the five main food groups shown above.
Consume foods and drinks that are high in fat, salt and sugar less often and in small amounts.
Most people in the UK eat and drink too many calories, too much fat, sugar and salt, and not enough fruit, vegetables, oily fish or fibre.
Learn more about the different food groups and how they form part of a healthy, balanced diet.
Do you find it difficult to make time to prepare healthy balanced meals for the whole family? If so, that might be part of the reason your child isn't consuming enough calories.
Try to make time for breakfast and dinner, and eat together as a family. Make mealtime a fun part of the day.
During the week, your child will eat lunch at school. It's impossible to monitor exactly what your child eats away from home, but you can help your child make healthy choices.
These days, school lunches are more likely to meet a child's nutritional requirements compared with the average packed lunch.
If you would prefer to make your child a packed lunch, make sure it is nutritionally balanced.
A healthier packed lunch should:
Get ideas from Change4Life for what to put in your child's school packed lunch.
To help your child gain weight, try increasing their portion sizes at mealtimes, especially for starchy foods such as bread, rice, pasta and potatoes.
Alternatively, if your child finds it hard to eat larger portions, try increasing the energy density of your child's meals, until they have reached a healthy weight.
Energy density is the amount of energy (calories) per gram of food. Higher energy density foods tend to be higher in fat, such as cheese, nuts, whole milk and nut butters.
You can also boost your child's daily calorie intake by providing healthier snacks.
Great snack ideas include:
Even if your child is underweight, it's still important that they're physically active.
Physical activity helps them develop strong, healthy bones and muscles. It's an important part of how they learn about themselves and the world. And, best of all, it's great fun.
Children over five should do a minimum of 60 minutes of at least moderate-intensity activity each day. But the amount of physical activity your child should do may be different if they're underweight. Your GP, practice nurse or school nurse can advise you on this.
Find ideas on how to get active with your child.
If you provide a healthy diet using these guidelines, you should see your child's weight and growth improve.
Keep regular records of your child's height and weight, and take your child back to your doctor to check that their weight gain is happening as it should.
Once your child has reached a healthy weight, their diet may need adjusting so that they don't become overweight.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.