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Obese children: causes, consequences, challenges

Jemma Mears
Senior Physiotherapist
Liver Unit
Birmingham Children's Hospital

Obesity is now considered to be a global epidemic.(1) It is one of the UK's largest health problems, and the prevalence of obesity across the nation has trebled in the past 20 years. The National Diet and Nutrition Survey found that one-quarter of men and one-fifth of women were obese,(2) and the National Audit Office has estimated that 1 in 4 of the adult population will be obese by 2010, and that the total cost to the NHS and the wider economy will be around £3.6 billion.(3)
With the incidence of obesity increasing across all age groups, there is an alarming proportion of children considered to be overweight or obese.
The 2002 Health Survey reports that from 1995 to 2002 the prevalence of obesity almost doubled among boys aged 2-15 years (from 2.9% to 5.7%) and increased by more than half among girls (from 4.9% to 7.8%). In total, in 2002, over a fifth of boys (21.8%) and over a quarter of girls (27.5%) were overweight or obese. Obesity prevalence in young adults aged 16-24 years was 9.2% for young men and 11.5% for young women, with, overall, about a third of young men (32.2% in total) and young women (32.8% in total) classified as overweight or obese. These figures may have surprised some, but for paediatric physiotherapists working in the UK, this unhappy picture is becoming all too familiar.
Childhood obesity is an important ­predictor of adult obesity.

Defining childhood obesity
Obesity in children is different from obesity in adults. The main difference is that all children and adolescents need to grow; during puberty, for example, a child's weight will double and height will increase by 20%. This has implications for the diagnosis, prevention and treatment of childhood obesity. It is important to ensure that any dietary restrictions and/or increases in activity do not affect children's normal growth and development.

Measuring childhood obesity
The waters are still muddy regarding the best and most accurate way to measure obesity in children. The body mass index (BMI) tends not to be used in isolation; instead, it is expressed as a BMI percentile in relation to an age- and sex-matched population. However, while for the adult population there are agreed cutoff points to define obesity, those for children vary depending on which reference you ­consult.
Body mass index (BMI) =weight (kg)/[height (m)]2
Weight maintenance, rather than weight loss - allowing the child to grow into their weight - can be a suitable and achievable goal for some children.

Consequences of childhood obesity
In the past, obesity-related health problems have been associated with adult populations. However, an increasing proportion of these illnesses are seen in children who are obese. These include:

  • Coronary heart disease.
  • Hypertension.
  • Type 2 diabetes.
  • Asthma.
  • Sleep apnoea.
  • Cancer.
  • Fatty liver disease.

Other obesity-associated problems that can severely affect a child's quality of life are:

  • Social and psychological problems.
  • Joint and back pain.
  • Stress incontinence.
  • Breathlessness.

In most cases, it is these related problems that are treated rather than the underlying cause.
The imperative when tackling childhood obesity is to take a holistic, multidisciplinary approach, using physical activity and dietary and lifestyle changes.

Reasons for increasing obesity
What has caused this increase in obesity that we are seeing in our school-aged population? Obesity occurs when we take in more energy than we expend. Simply, we are eating more and exercising less than we did 20 or so years ago. Therefore we are in a long-term positive energy balance.

Dietary factors
For today's children, high-density foods are far more readily available than they were for previous generations. There is frequent exposure to the advertising of junk food and a ready supply of fizzy drinks, crisps and chocolate in school vending machines. The number of fast-food outlets, offering "supersized" meals and free toys, has increased drastically, negatively influencing dietary choices.

Physical activity
Changed patterns of physical activity and the adoption of a more sedentary lifestyle are likely to be a factors associated with obesity. For example:

  • Fewer children are doing sports at school.
  • Fewer children are cycling or walking to school.
  • More children are being driven to school.
  • Children's pastimes, such as computer-based ­activities and watching television, are more ­sedentary.

Meeting the challenge
As a paediatric physiotherapist working on a supra-regional liver unit and specialising in liver disease, I have seen a definite rise in the number of children presenting with nonalcoholic fatty liver disease (NAFLD). Deposition of fat in the liver leads to varying degrees of inflammation and fibrosis, and it is not yet known whether some of these children will need liver transplantation in later life.
NAFLD is now recognised as an important childhood liver disease(5) and is thought to have direct links with childhood obesity. Treatment for NAFLD is weight reduction and regular exercise.(5)
Children referred to the liver unit are assessed by a multidisciplinary team, which comprises:

  • A specialist doctor.
  • A liaison nurse.
  • A dietitian.
  • A physiotherapist.
  • A psychologist.

Children receive specialist advice from the team, including a plan of action, and are reviewed regularly in follow-up clinics.

Supporting lifestyle change
The physiotherapy team provides much advice and encouragement on simple lifestyle changes and also educates the child and his or her parents on the best ways to exercise and combat the disease, giving advice on what types of exercise to take, how often and at what work intensity (see Table 1).


It is imperative that realistic goals are set with the families, so that they will see a change. The process of losing weight and increasing fitness is slow and can be really difficult for these children, many of whom do not have access to decent exercise facilities (see Table 2).


Some children are seen regularly in the physiotherapy gym at the hospital, where their progress is closely monitored. We have also engaged the help of the hospital youth worker, who has arranged locally based activities for the kids. Others are followed up more locally.
With an increasing number of obese children at the hospital, many paediatricians are trying to refer these children to my service, and, unfortunately, due to funding issues I am unable to see them all. We are currently looking into the feasibility of ­providing a trustwide service.

How primary care professionals can help
The challenge to the primary care professional is to encourage patients to incorporate physical activity into their daily life. Encourage 60 minutes of exercise per day. It can be in 20-minute sessions. The key concepts to get across are that it is important to minimise sedentary behaviour and that it doesn't matter what activity people get involved in as long as they are active!
Primary care professionals cannot be responsible for all aspects of treatment for an obese child. However, you can identify children who would benefit from input from other services and professional groups, and you are ideally placed to promote prevention and treatment of obesity in children:

  • Be proactive in identifying overweight children.
  • Refer to the appropriate agencies early.
  • Provide support and encouragement.
  • Be aware of local facilities and incentives.


  1. World Health Organization. Obesity, preventing and managing the global epidemic: report of the WHO consultation of obesity. Geneva: WHO; 1997.
  2. National Diet and Nutritional Survey: adults aged 19-64 years. Available from URL:
  3. Reilly JJ, Dorosty AR, Emmett PM. Prevalence of overweight and obesity in British children: cohort study. BMJ 1999;319:1039.
  4. Sproston K, Primatesta P, editors. Health survey 2002. The health of children and young people. London: TSO; 2003. Available from URL:
  5. Roberts EA. Steatohepatitis in ­children. Best Pract Res Clin Gastroenterol 2002;16:749-65.

National Obesity Forum
BBC Healthy Living webpages BBC website with lots of useful information about food and exercise for adults and children
Weight Wise Packed with loads of practical advice and support for anyone wanting to reach a healthier weight and stay there. The Weight Wise website is written and managed by registered ­dietitians and is evidence-based
Your Overweight Child
Starting point for parents and carers who want to help their ­overweight child regain confidence and achieve a healthy weight