Obesity is harder to assess in children than in adults as they are still growing, with increasing weight and height. The body mass index (BMI) uses weight/height comparison to assess obesity in children. The BMI is determined by weight in kilograms, divided by height in meters squared (kg/m2). In adults, being considered overweight is measured at a BMI above 25, with obesity determined at a BMI above 90. BMI in boys and girls changes substantially with age. The lowest values are 13.5-18 kg/m2, age 4-6 years, after which BMI will continue to increase as they grow older.
In Thailand, obesity in children is determined by a weight for height above the 120th percentile. In the U.S., obesity is defined as a BMI above the 95th percentile for children of the same age. Unfortunately, BMI-for-Age Growth Charts are not available in Thailand. If parents are concerned that their children may be obese, they should consult a pediatrician who can assess them, and refer to a specialist for treatment, if needed.
Approximately 14-15% of Thai children are obese. In 95% of all cases, the obesity is caused by consuming more calories than the body uses. However, certain other risk factors are also involved, such as a family history of obesity. Children of an obese father or mother have more than 4-5 times the risk of becoming obese, compared to children of normal-weight parents. Children with two obese parents are 13 times more likely to be obese. However, obesity in children can also be the result of endocrine causes, such as hypothyroidism or growth hormone deficiency, Cushing’s syndrome, insulin-excess syndromes, leptin deficiency or leptin receptor defects, as well as some genetic disorders, such as Prader-Willi syndrome.
Newborn babies who are over or underweight, children with an obese father or mother, and children who are obese when young are more likely to become obese adults. Overnutrition in babies is also a risk factor, with formula fed babies more likely to be obese than breastfed babies, and long-time breastfed babies, less likely to be obese than short-time breastfed babies.
There is little choice regarding weight loss medications and their indications for use in children. In most cases, it is much more appropriate and useful for children to alter their behavior and lifestyle. In younger children, portioning food by weight and avoiding sugary food is one way to combat obesity. In principle, as a child develops and his or her height increases, BMI is reduced. In older children or teenagers, weight control may be insufficient, and the best way to manage BMI is by having a well-balanced diet and sufficient exercise.
Drinking one can of soft drinks a day could lead to a 7 kg weight gain in one year. The best way to improve a child’s diet is to avoid sugar-loaded soft drinks, juices and carbonated drinks, or to opt for diet soft drinks containing artificial sweeteners, diluted fruit juice with a mix of 1 part water to 1 part juice. Real fruits are very beneficial as they are sources of nutrients and fiber that take time for the body to digest, making us feel full for longer periods of time. Also, avoid deep-fried or high-fat food, especially fast food, and change to eating meat that is cooked by boiling instead of deep frying. When consuming stir-fried or shallow fried food, it is better if cooked using a non-stick frying pan, as this requires only a small amount of oil.
Moreover, it is highly beneficial for children, indeed for all of us, to exercise at least 20-30 minutes a day, four days a week, as this helps burn calories and lose weight more efficiently. To treat obesity in children, encouragement, and support from parents and family members, setting good dietary and exercise examples, is very important.
Most importantly, overweight children will grow into overweight adults. Research from overseas has found that extreme obesity cuts life expectancy by an average of 5-20 years.
Common complications of obesity in children include:
Obesity has become more common in younger children. Some obese people may have darker skin of the neck, armpits and groin (Acanthosis Nigricans) due to high insulin levels in the bloodstream. This darkened skin may look like a buildup of dead skin cells, but it is not. It cannot be removed by rubbing or applying a cream, but it will fade with weight loss. Darkened skin is a warning that if weight isn’t shed, the child is more likely to develop diabetes in the future. Early signs include eating a lot but losing weight, increased thirst and frequent urination. Some children may experience bedwetting, and other complications include high blood cholesterol. In most cases, the conditions improve after weight loss, and only a few patients will need to take medications. Fatty liver is another condition found in obese children with high blood cholesterol. However, this condition also disappears after weight loss. To ensure a long and healthy life for your children, make sure you follow our advice on controlling their weight while they are still children, through a healthy diet and plenty of exercise. [PS1]
M.D, Faculty of Medicine Siriraj Hospital, Mahidol University, 2001.