USA: The prevalence of adult obesity has increased by 50% within 7 years
While in industrialized countries children from families with a poor socio-economic status are more often overweight, the opposite holds true for children in developing countries, where children of the upper middle class are more likely to be overweight. It has been shown that childhood obesity is predictive for obesity in adulthood.
Worldwide more than one billion adults are overweight and over 300 million are obese. World Health Organization (WHO) has declared overweight as one of the top five risk conditions in developed nations. Obesity related diseases have also been observed in children, though to a lesser extent than in adults. Obese children and adolescents are more likely to have problems to find a place in the society which matches with their abilities. Obesity, once established, is difficult to treat. Therefore, steps should be taken to prevent childhood obesity. Prevention of childhood obesity is a public health agenda as well as a high priority research goal
Obesity is generally defined as the abnormal or excessive accumulation of fat to the extent that health may be impaired. Body Mass index is a ratio of the body weight in kilograms divided by the square of the height in meters. BMI is used for assessment of obesity in children and adolescents, as well as adults.
Hazards of childhood obesity
Immediate health problems of overweight and obese children include social isolation and potential psychological dysfunction. Young overweight children have been described by their peers as ugly, stupid, dishonest and lazy and they may experience teasing and social isolation as a result. Such children are also at greater risk of certain diseases than their lean counterparts. In the short term, overweight and obese children are more likely to develop certain gastrointestinal, cardiovascular, endocrine and orthopedic problems than their lean peers that may be worsened in the long term. Further, overweight and obese girls are more likely to develop reproductive system abnormalities, such as early onset of puberty and menarche, and polycystic ovary syndrome.
How to prevent childhood obesity
Childhood obesity needs to be addressed by a public health approach as well as interventions aimed at individual subjects. Early intervention of obesity in a pediatric population is superior to intervention strategies directed at adults. Prevention of childhood obesity may be the only effective treatment of adult obesity. Prevention of obesity should commence very early in life. For example, breastfeeding an infant is preferable to the use of a formula and may contribute to the prevention of obesity. Further, young children’s food and activity choices can be influenced by early intervention and guidance and habits learned early in life are likely to carry through to adulthood.
In practice different prevention strategies are used. The intervention strategies include:
- Universal prevention
- Selective prevention
- Targeted or secondary prevention
Universal prevention strategies include intervention strategies that are directed at everyone in a community with the aim to stabilize or to reduce mean BMI within a population. Selective prevention strategies include intervention strategies that are directed at high risk individuals (e.g. children of obese parents). Targeted or secondary prevention include intervention strategies that are directed at overweight and obese children and adolescents to prevent further weight gain and/or to reduce body weight.
Interventions to prevent weight gain include school programs, correspondence programs, individual or group counseling including behavior change methods and a public health approach.
School-based interventions alone improve some aspects of healthy behaviors but are without effect on nutritional status. Long-term effective management of overweight and obese children by a family-based intervention was reported by some authors. All family-based intervention studies resulted in long-term changes in health-related behaviors in obese children and adolescents but had no or only moderate long-term effects on nutritional status. KOPS (Kiel Obesity Prevention Study) was started in 1996 which combined school based and family based interventions.
Health promotion for adolescents can be done in general practice also. Obesity in adults can be prevented by treating obesity during childhood in primary care. But the effectiveness of these various interventions is not well documented.
To prevent childhood obesity action is primarily required at societal level to counter the environmental influences on physical activity and dietary intake (i.e. universal rather than targeted prevention). Risk factors for developing obesity include genetic, social and behavioral factors. Since genetic and social factors cannot be changed, prevention programs have to focus on behavioral changes including increasing physical activity and reducing energy intake. Energy balance occurs when energy intake (food intake) equals energy expenditure. Energy intake in excess of energy expenditure results in weight gain. Total energy expenditure consists of three components:
- Resting metabolic rate (60–70 per cent)
- Thermic effect of food (15–20 per cent)
- Energy expended in physical activity (20–25 per cent)
Physical activity is the component most susceptible to change. Therefore, interventions aimed at preventing childhood obesity should focus on factors that influence food intake and physical activity.
Interventions within the family
Family lifestyles play a central role in the development of children’s food preferences and activity choices. Parents in particular have a strong influence on their children’s lifestyles through modeling and education. Therefore it is vital that strategies aimed at preventing childhood obesity involve parents and the wider family unit. Nutritional guidelines to prevent obesity in young children include:
- Prepare a variety of foods (with servings from all five groups: grains and cereals, meat and protein, fruit and vegetables, dairy, fats)
- Eat home-prepared meals as often as possible
- Provide plenty of fruits, vegetables and food rich in starch and fiber (wholemeal bread, pasta, rice or cereals instead of white equivalents)
- Avoid consumption of high-fat foods (choose semi-skimmed milk, low-fat margarines, spreads and yoghurts)
- Reduce the use of fat during food preparation (grill, boil or steam foods rather than frying)
- Minimize the use of high-sugar foods. For example, avoid adding sugar to cereals and drinks
- Limit consumption of sugar-sweetened soft drinks; as an alternative encourage drinking water
- Encourage the consumption of food and drink in the kitchen or at the dining table
- Avoid eating at times other than mealtimes and recognized snack periods
- Eat family meals together whenever possible
- Serve appropriate portion sizes
- Encourage children to eat a healthy breakfast and avoid skipping meals
- Minimize unhealthy snacking (for example, high in sugar and/or fat), especially after dinnertime
- Make healthy snacks (fruits, carrots and other vegetables) attractive and readily available
- Provide a healthy lunch box to take to school
- Teach children that it is okay to leave food on their plate when they have had sufficient
- Do not use food as a reward
The physical activity guidelines to prevent obesity in young children include:
- Provide opportunities for safe active play both inside and outside the home
- Expose children to as many different kinds of physical activity as possible
- Enroll children in sports clubs
- Organize physical activities with the entire family at least once a week
- Encourage walking or cycling to and from school or the shop
- Encourage taking the stairs rather than the elevator. If there are too many floors, encourage walking some of the flights and try to increase gradually the number of flights walked
- Involve the children in home activities such as doing the dishes, cleaning their room, washing the car, gardening, walking the dog etc.
- Limit time watching television or playing computer games to less than two hours per day
- Only allow children to watch television if they have been physically active for at least one hour
- Do not allow televisions and computer games in children’s bedrooms
Schools are an ideal setting for the prevention of childhood obesity. School programs offer many advantages including large numbers of children to be reached, guidance can be continuous, costs can be minimized and parents can be easily involved in the program. Schools have the potential and the personnel to promote changes in physical activity and eating behavior.
Physical education classes provide a unique opportunity to contribute to increased physical activity levels in children. There is also great potential to utilize break times better, including before, during and after school for physical activity and sports. Most schools have a range of sport facilities and equipment and generally these are only used minimally after school hours. The school environment also provides great potential for multiple food and nutrition activities, experiences and exposures.
Physical education teachers could act as coordinators of school-based intervention programs for the prevention of obesity. In addition, other school or community staff such as a nurse or doctor could screen children for overweight. Children identified as overweight could be referred to a clinic based weight management program to prevent further weight gain.
Interventions within the community
Government needs to financially and physically support obesity prevention programs. In terms of supporting healthy eating, governments should take action to make healthy food (such as fresh fruits and vegetables) easily available to those who perceive healthy food as expensive or difficult to obtain.
Government can legislate on food labeling, food advertisements directed at children, and school food policies. The government should provide safe environment and roads to support physical activity like walking and cycling. In public buildings they should provide staircases instead of elevators. The school curricula should be expanded in terms of physical activity and health education.