Patient information from BMJ

Weight problems in children

Last published:Dec 06, 2021

It can be upsetting to hear that your child has a weight problem. But it’s a problem that's facing many children. To give your child the best chance of a healthy, happy life, you’ll want to help them to reach and maintain a healthy weight.

When is a child overweight?

Most doctors use the body mass index (BMI for short) to find out whether people are at a healthy weight. Your BMI is a number that's worked out from your height and weight.

To tell if children are overweight, doctors compare their BMI to that of other children who are the same age and sex. They do this using child growth charts.

When doctors talk about children being overweight, they mean their BMI is higher than that of most children who are the same age and sex.

You might be shocked to be told that your child is overweight, and you might feel angry or guilty. But parents often don’t realise that their child is overweight.

There are lots of reasons for this. Children grow at different rates, and a parent may think a child has just put on a bit of ‘puppy fat’. Also, if the child’s school friends or relatives are also overweight, parents may think their child’s weight is normal compared with the weight of those around them.

The reasons why children become overweight are usually the same as the reasons why adults become overweight: they are regularly eating more calories than their body is using up as energy. Calories that are not used as energy are stored as fat.

There are a few main factors that determine whether a child eats more calories than they use:

• The type of food the child eats (his or her diet)

• How much the child eats

• How much exercise the child takes.

Some parents think their child must be overweight because of their genes. It’s true that a child’s genes can make them more likely to put on weight. But it’s still important to help your child to eat healthily, take exercise, and aim to achieve a healthy weight.

Rarely, other issues may cause a child to gain weight. These include hormonal issues, medicines, and genetic conditions (for example, Prader-Willi syndrome). Your doctor will check to make sure nothing unusual is causing your child's weight gain.

What treatments work?

If your child weighs more than is healthy, your doctor may suggest they try to keep their weight steady for six months or longer. That way, they may ‘grow into’ a healthy weight, rather than needing to lose weight.

But if your child is very overweight, your doctor will probably recommend they try to lose weight. Either way, the best approach usually involves a combination of changing what they eat (their diet), exercising, and adopting healthier habits.

Diet, exercise, and changing habits

For most overweight children, the best approach to achieving a healthy weight involves eating better, exercising more, and changing unhealthy behaviours.

Children have the best chance of success if their family is actively involved. If all the family agrees to the same rules (for example, not eating snacks in front of the television, or always going for a long walk at the weekends) then it’s easier for the child to stick to them.

• Improving a child’s diet. This often involves eating more fruit and vegetables, cutting out sugary drinks, avoiding fast food, and not having high-calorie snacks like biscuits or crisps between meals. (For more information, see our leaflet Weight problems in children: improving a child's diet.)

• Increasing physical activity. Doctors usually recommend children get at least 60 minutes of physical activity a day. There are many different ways to increase activity, such as taking part in sports, going on regular family walks, and walking or cycling to school.

  Most doctors also recommend limiting a child's screen time (including television, computer and video games, and internet) to less than two hours a day. (For more information, see our leaflet Weight problems in children: increasing physical activity.)

• Changing unhealthy habits. This can include setting goals for healthy eating and activity, tackling hard-to-change habits, and helping your child have more self-confidence and feel better about themselves.

  Many children benefit from seeing a counsellor who specialises in helping children manage their weight. (For more information, see our leaflet Weight problems in children: changing unhealthy habits.)

All three of these steps are important for helping a child achieve a healthy weight. Your doctor might help you draw up a plan for things you can do at home, or suggest your child sees a counsellor to help you make a plan. Or your child might be referred to hospital to join a specialist programme for overweight children.

Once a child has reached a healthy weight, it’s important that they get lots of help and support to not slip back into unhealthy habits.

Medicines and surgery

Medicines to reduce weight are not often used in children. They are usually only used if a child is older (at least 12) and their weight is putting their health at serious risk.

One medicine that is sometimes used is called orlistat. Another option is a medicine called metformin, which is usually used to treat people with diabetes. However, there isn’t enough research to say for certain whether these medicines work for children and are safe for them.

Weight-loss surgery is occasionally used for children, but only if they're older (in their teens) and are extremely overweight. It is seen as a last resort and only used in exceptional cases where an older child's health is at serious risk. Weight-loss surgery reduces the size of the stomach, so the person feels full sooner and can only eat a small amount at a time.

Weight-loss surgery often works for adults, helping them lose large amounts of weight. There hasn’t been enough research to say for certain whether weight-loss surgery for children is safe and works in the long term.

What will happen to my child?

Being overweight can make a child feel unhappy and bad about themselves. It also puts them at risk of health problems, both now and in the future.

• Studies show that overweight children have a greater chance of certain health problems, including asthma, high blood pressure, high cholesterol, and problems with the way their body controls blood sugar levels (insulin resistance and diabetes).

• Not all children who are overweight grow up to be overweight adults. But overweight children are more likely than other children to be overweight as they get older.

  This can increase their chances of having serious health problems as adults. These include high blood pressure, heart disease, diabetes, osteoarthritis, and some cancers.

For these reasons, it’s important to help your child reach and maintain a healthy weight.