Childhood obesity: time for action, not complacency

Definitions are unclear, but effective interventions exist

The lack of agreement between different studies over the classification of obesity in children and adolescents makes it impossible to give an overview of the global prevalence of obesity for these age groups. Nevertheless, whatever method is used to classify obesity, studies consistently report a high prevalence of obesity and rates are on the increase.1 The national studies of health and growth carried out from 1972 to 1990 on English and Scottish children showed a roughly twofold increase in weight for height in all age groups and both sexes.2 Similar trends have been observed in Europe and the United States.3 Paediatricians face problems of overweight in around one in four of their patients. Interestingly, childhood obesity is not only confined to industrialised countries.1 Therefore a rational clinical approach needs to be applied to preventing and treating this disorder.

The most successful weight reduction programmes are those that combine diet and exercise within a framework of behaviour modification.4-5 Limited information is available about the use of aggressive treatment such as drugs and surgery for children, although such treatments are generally discouraged at that age. Evaluation of obese children and adolescents should include assessment of weight for height and body fatness; rule out endocrine and genetic causes; and evaluate other risk factors, such as those for cardiovascular disease, cancer, diabetes, orthopaedic disorders, and psychological problems. Treatment of obesity is most successful if realistic goals are set; a balanced diet is emphasised; a safe rate of weight loss of about 0.5 kg a week is achieved through moderate reduction of energy intake (about 20-25% decrease); increased physical activity is emphasised as much as diet; parental support is strong; and behaviour therapy is provided to help both child and parents achieve the diet, exercise, and behaviour goals.

Dietary assessment helps to identify both the amount eaten and the child's and family's eating patterns. The prescribed diet should be simple, explicit, and unambiguous so that it is easy to implement and monitor and not subject to confusion or easy rationalisation of exceptions. Epstein et al developed the “traffic light diet,”6 which defines all foods by their energy content into red (stop), yellow (proceed with caution), and green (go). Children count the number of servings consumed for each colour as well as calories.

To lose 0.5 kg a week, 14.6 MJ (3500 kcal) must be eliminated (2.1 MJ (500 kcal) a day) through a combination of decreased energy intake (diet) and increased energy expenditure (physical activity). Only small reductions in energy intake are recommended for overweight children, as an adequate intake of both energy and nutrients is required for normal growth and development. Reducing the excess energy intake can be achieved by limiting takeaway and ready prepared foods, which tend to be particularly energy dense, and by decreasing portion sizes. Children should be encouraged to eat fewer high fat snacks such as crisps and biscuits and to avoid consuming a large proportion of total energy from sweetened drinks. Another approach to dietary change focuses on reshaping long-term food preferences.7 However, there are insufficient data to judge the potential benefits of altering food preferences or sensory specific satiety.

The rapid rise in childhood obesity has been mirrored by an explosion of sedentary leisure pursuits for children such as computers, video games, and television watching.8 Increased general activity and play rather than competitive sport and structured exercise seem to be more effective.9 Adherence may be improved by making the activity enjoyable, increasing the choice over type and level of activities, and providing positive reinforcement of even small achievements. Being active may also compete with snacking and thereby make diet adherence easier.

There is experimental evidence that self monitoring and goal setting result in greater short term weight losses.7-10 In establishing both short and longer term goals it is important to make them specific, measurable, challenging, yet achievable. Contracts can be used to help maintain focus on specific behavioural goals and provide a structure for rewarding desired changes.

Three key settings for implementing childhood obesity management support programmes have been identified: the family, the school, and primary care. The provision of education on eating and lifestyle behaviour to parents has been shown significantly to reduce the prevalence of obesity in children of participating families.10 By directing preventive efforts at the family of susceptible children there is the added bonus that all members of the family are likely to benefit. Holding classroom lessons on nutrition and physical health was accompanied by improvements in indices of fitness and body fat levels.11 Nevertheless, maintaining these programmes in the school curriculum in the long term has proved difficult owing to competition for school time, the need for teacher supervision, and financial limitations.

The delivery of programmes through primary care has received little formal assessment, and its potential role seems to be undervalued and underused.12 Frequent contact with health professionals from an early age has been identified as an important strategy for effective management of obese children through the provision of advice, encouragement, and support for adopting healthy household eating and exercise patterns at an early stage in life.12