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Childhood obesity

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If your child is overweight or obese, they have an increased risk of developing various health problems and are more likely to become an overweight adult.

If your child is overweight or obese, this means that they are carrying excess body fat.

If the extra weight they are carrying is treated in childhood, some of these health problems may be reversed, or even prevented. Your child is also more likely to grow into an adult with a healthy weight. The main way to treat a child who is overweight or obese is to look at changes that can be made to their lifestyle. Such changes include eating more healthily and doing plenty of physical activity. Children learn by example so changes that involve the whole family are best.

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How do you know if your child is overweight or obese?

Doctors, nurses and other healthcare professionals can look to see whether your child is overweight or obese by calculating their body mass index (BMI). BMI is a measurement of your child's weight in relation to their height. BMI is calculated by dividing your child's weight in kg by their height in metres squared (weight (kg)/height m2). However, it is important to know that a child's BMI is not interpreted in the same way as an adult's BMI. Instead, their BMI is charted on special growth charts. These charts can show how your child's BMI compares with the normal range for children of a similar age, sex and ethnic background.

Your child's doctor, nurse or other healthcare professional can check your child's BMI against these standardised charts to determine if they are overweight or obese. You can also visit MEND's Mytime Active website for a calculator specifically designed for children. You can see the charts that are used (WHO-UK BMI charts) by following the link in 'Further Reading and References' below.

What are the health risks for your child of being overweight or obese?

Children who are overweight or obese can develop health problems during childhood because of their weight. Health problems can include type 2 diabetes, high blood pressure, high cholesterol levels, fatty liver disease, gallstones and risk factors for heart disease. These health problems have traditionally been problems just affecting adults, with overweight and obese adults having an increased risk of developing them. But because of the rises in the levels of childhood obesity, some of these obesity-related health problems are now affecting younger people.

A child who is overweight or obese also has an increased risk of:

  • Joint problems, including wear and tear (osteoarthritis) and separation of the ball of the hip joint from the upper end of the thigh bone (slipped capital femoral epiphysis). Obese children are also more likely to develop bow legs and are more likely to have fractures of bones.

  • Going through puberty early.

  • Breathing problems, including worsening of asthma, difficulties with your child's breathing whilst they are asleep (obstructive sleep apnoea) and feeling out of breath easily when they are exercising.

  • Developing iron deficiency and vitamin D deficiency.

  • Being overweight or obese as an adult (more than half of children who are obese will grow up to be obese as adults).

  • Developing heart problems as an adult.

Being overweight or obese as a child or teenager can also have psychological effects for some. It can lead to low self-esteem and a lack of confidence. A child may be subject to bullying because of their weight. They may become withdrawn and avoid social contact. It may lead to low mood and, in severe cases, depression.

If being overweight or obese is recognised and treated in childhood and the teenage years, some of these health problems may be reversed, or even prevented. The child is also more likely to grow into an adult who has a healthy weight.

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Childhood obesity statistics

The most recent figures show that in the UK In 2015/16, about 1 in 5 children in Reception class (age 4-5 years) and over 1 in 3 children in Year 6 (age 10-11 years) were measured as obese or overweight..

The rapid rise in obesity seen since the 1970s has been called the obesity epidemic. Overall, the obesity rate in children is decreasing, but a detailed look at the statistics reveals considerable variation. For example, in Reception there is a significant decrease in the number of obese boys, but in girls the decrease is much smaller. In Year 6, there is a significant increase in obese boys and girls. The UK still has one of the highest rates of childhood obesity in Europe.

Causes of childhood obesity

It used to be thought that for anyone (including children), your weight depended entirely on how much energy you take in (in the form of calories from food and drink) and how much energy your body uses (burns) up. Logically, it was thought that if you take in more energy than you use, it would be converted to fat and stored in the body. So the theory was that if you increased the energy you used (by exercising) and/or reduced the calories you were taking in (by eating less) you would lose weight.

It's now known that this model is too simple. There are body systems which try to keep your weight stable. Research has identified nerve connections between the stomach and the brain. Body chemicals (hormones) are involved, too. It's now known that various parts of the body communicate with each other to keep your body weight stable.

The latest theory is that if you eat less you become more hungry, and you become less active. Increasing your activity, as in exercise, you become more hungry and compensate by eating more later on. You also become tired and reduce your activity after a bout of exercise. Eating more calories increases your energy and makes you more active.

The body therefore adjusts to how many calories you eat by increasing or decreasing your activity levels. But there are foods that cancel out the body's fight to keep its weight stable, and knowing about these can help an obese child to slim down. Foods high in fat and sugar stimulate the reward centre in the brain. We all know how difficult it is to eat just one chocolate biscuit.

Refined carbohydrates, fructose and sugar-sweetened drinks seem to be the worst culprits. They don't ease hunger pangs, and the increased calorie intake isn't matched by an increase in energy levels.

To read more about the science of gaining and losing weight, see the separate leaflet called Weight Loss (Weight Reduction).

The reasons why energy taken in may not balance energy used up and may lead to weight gain in children, include the following:

How much a child eats and drinks

Portion size is important. As suggested above, foods which over-ride the body's appetite control system, such as sugary drinks and fatty foods, lead to children taking in more quantities than they need.

A lack of physical activity

Exercise is important but only if the child eats the right type of food to compensate for the energy used up. In other words, a child who fills up with sweets and chocolates because they are hungry after a bout of exercise is unlikely to lose much weight.

Long periods without exercise also contribute - for example, spending many hours watching television or playing video games. Having parents who are inactive can also increase a child's risk of being overweight or obese.

Your parents

Being overweight or obese does run in families. It is thought that 5 out of 10 children who have one parent who is obese will become obese themselves. And 8 out of 10 children who have two parents who are obese will also become obese themselves.

This may partly be due to learning bad eating habits from your parents as a child. However, some people actually inherit a tendency in their genes that makes them prone to overeating. It is not fully understood how this genetic factor works but it may well be associated with the hormones involved in appetite control that we have already mentioned.

If you do inherit a tendency to overeat, it is not inevitable that you will become overweight or obese. You can learn about the power of your appetite, the ways to resist it, how to be strict on what you eat and the benefits of doing some regular physical activity. But you are likely to struggle more than most people where your weight is concerned. You may find it more difficult to stop yourself from gaining weight or to lose weight.

Research has also shown that children who are born to mothers who are overweight, or mothers who develop diabetes during their pregnancy, are more likely to be overweight or obese themselves.

Lack of sleep

Not getting enough sleep has been suggested as another possible risk factor for obesity in children. There seems to be a trend of children going to bed later but, also, too little physical exercise can lead to poor sleep.

Two hormones called leptin and ghrelin may be important here. Leptin is released by fat cells to tell your brain that fat stores are sufficient. Ghrelin is released by your stomach as a signal of hunger. In someone who does not have enough sleep, leptin levels are low and ghrelin levels are high. These changes in hormone levels may encourage a child to eat more.

Medical problems

Rarely, a child has a medical cause for being overweight or obese. For example, there are some rare genetic diseases that can cause overweight and obesity in children. Conditions such as an underactive thyroid gland (hypothyroidism) or other hormone problems may also be a cause. Some medicines can also make children more likely to put on weight. However, in general, a medical cause for being overweight or obese is unusual.

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What should I do if I am worried that my child is overweight or obese?

If you are worried that your child may be overweight or obese, you can discuss this with your doctor, your practice nurse or another healthcare professional that you trust. They may be able to suggest ways in which you can help your child, or refer you to other professionals who may be able to help. There may be some specific schemes or services in your local area specially set up to help prevent or manage overweight and obesity in children. For example, there may be a healthy living programme in your area, such as a MEND course (see link under 'Further Reading and References', below). Your child's healthcare professional should be able to advise about this. In the UK , the National Institute for Health and Care Excellence (NICE) guidelines have recommended more lifestyle-based weight management programmes be developed across the country. These services would offer advice and help using multiple strategies.

Children who are seriously overweight may be referred by their doctor to a special clinic at a hospital. Usually, such clinics have a team of doctors, nurses and other healthcare professionals who are experts in dealing with overweight and obesity in children. However, many overweight children do not need to be referred for specialist care.

How much weight should a child lose if they are overweight or obese?

In general, rapid weight loss or strict dieting is not recommended for children who are still growing, unless this has been specifically advised by a specialist. For most children, the aim is usually to keep the weight at the same level rather than weight loss. As they grow and their height increases, the child should either not gain any weight as well or their weight gain should be slower than their height gain. Sometimes, if teenagers have stopped growing, weight loss of around 0.5 kg per week may be appropriate. Your child's healthcare professional will be able to advise what is best for them.

Treatment for childhood obesity

The main way to treat a child who is overweight or obese is to look at changes that can be made to their lifestyle. Changes that involve the whole family are best. Other family members who are overweight may also benefit at the same time. Remember that as a parent or carer, you act as an important role model for your child and you can help them to stay healthy.

The two main lifestyle changes that are advised are for your child to eat more healthily and do plenty of physical activity. Small, gradual changes may be best. Your child will then be more likely to stick to these changes in the long term.

As a parent or carer, you should try to be involved as much as possible in helping your child make these changes. However, some older teenagers may prefer to take responsibility for themselves. Think about how your child's progress is going to be monitored. Discuss this with their healthcare professional. At every opportunity, give praise and encourage your child in what they are doing.

See separate leaflet called Weight Loss (Weight Reduction) for more details.

Eating more healthily

Overweight children should be encouraged to eat more healthily and to reduce the amount of fattening foods that they eat. In most cases, as a parent, you will need to take responsibility for making changes to your child's diet, especially if your child is under the age of 12 years. However, it is important to involve the child as much as possible and to listen to their ideas and preferences when deciding what changes to make to the food that they eat.

Your healthcare professional may ask you to keep a diary of the food that your child eats. They may then have specific recommendations for changes to make. Sometimes a referral to a dietician may be suggested.

Some suggestions that may be helpful include:

  • Aim for a balanced and varied diet for the whole family.

  • Encourage your child to eat meals at regular times and to watch how often they are eating. They should avoid snacking as much as possible.

  • Try to eat meals in a sociable atmosphere as a family, without distractions. For example, do not eat in front of the television.

  • If snacks are eaten, they should be healthy snacks (for example, fruit or raw vegetables) instead of sweets, chocolates, crisps, biscuits and cakes.

  • Low-calorie drinks are better than sugary drinks (water is best).

  • Snacks or food should not be used as a reward.

  • Encourage your child to watch the portion sizes of the food that they are eating.

  • Make sure that your child eats plenty of foods high in fibre. Foods rich in fibre include wholegrain bread, brown rice and pasta, oats, peas, lentils, grain, beans, fruit, vegetables and seeds. Amongst other things, foods high in fibre will help to fill your child up.

  • Aim for at least five portions, or ideally 7-9 portions, of a variety of fruit and vegetables per day for your child.

  • Children need fat in their diet but aim to grill, boil or bake rather than fry foods.

Doing plenty of physical activity

It is recommended that all children should do at least 60 minutes of moderate physical activity every day. Some suggest that children who are overweight or obese should even do more than this. This 60 minutes does not have to be done all at once and can be broken up into 10- or 15-minute blocks. Try to find activities that your child enjoys, rather than something they don't want to do. This way they are more likely to continue with it. Also, you should encourage your child to become generally less inactive (sedentary). The amount of time that they spend doing sedentary activities, such as watching television, using a computer, or playing video games, should be less than two hours each day.

As parents and carers, there are some ways that you can encourage your child to become more physically active. For example:

  • Encourage active play for your child, including games that involve moving around a lot, such as skipping, dancing, running or ball games.

  • Encourage your child to spend less time sitting doing sedentary activities.

  • Build physical activity into your child's life in general. Try to be more active as a family. For example, walking or cycling to school and the shops, going swimming or to the park together. Again, remember that as a parent or carer, you act as a role model. Lead by example.

  • Help children to take part regularly in structured physical activities that they enjoy. This may include dancing, football or other sports or swimming.

Treatment with medicines

As a rule, treatment with medicines is not usually used to help children and teenagers lose weight. However, in rare cases, the medicine orlistat may be prescribed to help children who are severely obese; in particular, if they have started to develop health problems because of their obesity. In exceptional cases, it has been prescribed to children aged under 12 years, but most children are teenagers. It is recommended that it should only be prescribed by an experienced specialist team. Orlistat works by interfering with the way that fat is digested and absorbed into the body. If a teenager needs to take orlistat for more than twelve weeks it is usual for this to be under the guidance of a specialist weight loss clinic. If prescribed this medicine, the child or teenager will need regular follow-up.

See separate leaflet called Orlistat (Weight Loss Medicine).

Involving a specialist

Apart from prescribing orlistat long-term, a specialist may need to be involved in other aspects of your child's management, especially if your child has other medical conditions or complex needs such as learning disabilities.

Weight loss surgery

Surgery to help weight loss, also called bariatric surgery, is not usually carried out in children. However, in exceptional circumstances, it may be considered as an option for teenagers who have already gone through puberty and who are severely obese with severe health problems caused by their obesity.

Psychological support

As mentioned above, being overweight or obese as a child may lead to psychological problems for some children. As a parent or carer, you may feel able to discuss with your child how they are feeling. Or, you may wish to involve your child's healthcare professional. Counselling or specialist help to increase confidence and self-esteem and to help develop coping strategies for teasing or bullying is sometimes needed.

Can obesity in children be prevented?

Yes. As a parent or carer, you can help to prevent your child becoming overweight or obese by:

  • Aiming for a healthy, balanced and varied diet for your whole family.

  • Ensuring that your child is getting the recommended amount of physical activity (at least 60 minutes of moderate physical activity a day).

  • Limiting the amount of time that your child spends being inactive (sedentary) - for example, less time in front of the computer or watching TV.

  • Building physical activity into your family's life in general.

  • Encouraging a healthy lifestyle for your whole family.

If your child is in Reception or Year 6, their BMI will be checked as part of the National Child Measurement Programme. If it falls outside the normal range, you may receive a letter from the school. Some parents see this as an intrusion but it is meant to be a helpful warning that you need to take some action for the sake of your child's health.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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