In many obese people, the roots of their disorder can be traced back to childhood. Obesity tends to persist through life. While most obese infants will not remain so, they are at increased risk of becoming obese children. These children are in turn more likely to become obese adolescents, who are then very likely to remain obese as adults. Evaluation and treatment of obesity in childhood offers the best hope for preventing disease progression with its associated morbidities into adulthood.

Epidemiology

The persistence of obesity into adulthood depends on several factors, including the age at which the child becomes obese, the severity of the disease and the presence of obesity in at least one parent. Overweight in a child under three years of age does not predict future obesity, unless at least one parent is also obese. After age three, however, the likelihood that obesity will persist into adulthood increases with the advancing age of the child and is higher in children with severe obesity in all age groups. After an obese child reaches six years of age, the probability that obesity persists exceeds 50 percent, and 70 to 80 percent of obese adolescents will remain so as adults. The presence of obesity in at least one parent increases the risk of persistence in children at every age.

Pathophysiology

A person gains weight when energy input exceeds energy output. Energy input is food. Several studies have shown that, on average, obese children do not consume significantly more calories that their thin peers. Energy output comprises the basal metabolic rate, the thermal effect of food and activity. The thermal effect of food is the energy required to absorb and digest meals. Of these variables, activity is the one least influenced by genetic inheritance and is therefore the one most susceptible to change. By measure, 3,500 calories is equivalent to one pound; thus, an excess of only 50 to 100 calories per day will lead to a five- to ten-pound weight gain over one year. As a result, a relatively small imbalance between energy input and output can lead to significant weight gain over time. In fact, most obese children demonstrate a slow but consistent weight gain over several years.

Evaluation of Obese Children

Only a small percentage of childhood obesity is associated with a hormonal or genetic defect, with the remainder being idiopathic in nature. Obese children should be evaluated for associated morbidity. This includes an assessment of cardiac risk factors, weight-related orthopedic problems, skin disorders and potential psychiatric sequelae.

Cardiac risk factors include a family history of early cardiovascular disease, high cholesterol and blood pressure levels, cigarette smoking, the presence of diabetes mellitus and decreased physical activity. The National Cholesterol Education Program recommends that physicians screen all obese children over two years of age for elevated cholesterol levels.

Obese children also have increased average blood pressure, heart rate and cardiac output when compared to non-obese peers. Tobacco use should be ascertained in all young people, as this represents an independent risk for cardiovascular disease. Finally, the presence of diabetes should be considered in all morbidly obese children. While overt type 2 diabetes mellitus is rare in childhood, hyper-insulinemia and glucose intolerance are nearly universal in morbidly obese children.

The child's level of physical activity should be assessed, not only for cardiac risk evaluation, but also to help guide future treatment. Television viewing patterns should be reviewed, since television viewing has been shown to be associated with obesity in childhood.

Because they carry excess weight, obese children are at increased risk for orthopedic problems. Obese children are also more prone to skin disorders than are non-obese children, especially if deep skin folds are present. It is essential to address psychiatric problems, including depression, poor self-esteem, negative self-image and withdrawal from peers.

Treatment

When a child develops obesity, a serious attempt to treat it should be undertaken. Components of a successful plan include:

Setting Goals for Weight Loss
Weight loss goals should be obtainable and should allow for normal growth. Goals should initiallybe small, so that the child doesn't become overwhelmed or discouraged. Five to ten pounds is a reasonable first goal, or, if preferred, a rate of one to four pounds per month can be established.

Dietary Management
The child should maintain a food record (diary) periodically to aid in dietary assessment. The food diary should include not only the type and quantity of food eaten, but also where it was eaten, the time of day, and who else was present. Keep in mind that 3,500 calories must be eliminated by diet and exercise to lose one pound of weight. A calorie-per-day guide should be established that follows the guidelines for percentages of fat, protein and carbohydrates. Dietary fiber is also important since it increases satiety and displaces fat in the diet.

Physical Activity
Exercise is necessary to maintain weight loss and to redistribute body fat into muscle. It is, therefore,an essential part of any weight management program. Initial exercise recommendations should be small and exercise levels should be increased slowly, to avoid possible discouragement. A reasonable goal is 20 to 30 minutes of moderate activity per day, in addition to whatever exercise the child gets during the school day.

Behavior Modification
Areas of modification include:

Self-monitoring -- accomplished by food and activity diaries, which help the child become more
aware of his or her eating and exercise patterns.

Nutrition Education -- aimed at both the child and the family. It should include the components of a healthy diet and an understanding of food labels and the importance of dietary fiber. The patient
should be taught that 3,500 calories equals one pound, that there are nine calories per gram of fat
and only four calories per gram of carbohydrate or protein. Furthermore, 25 percent of the energy
from carbohydrates will be used in its conversion and storage as fat in the body.

Stimulus Control -- limiting the amount of fattening foods in the house, eating all meals at the dinner table and at designated times, serving food only once before storing leftovers (no second helpings). Parents should not verbally encourage the child to eat, and the child should not be forced to finish the entire meal.

Eating Behavior -- taking smaller bites, chewing food longer, putting the fork down between bites
and leaving some food on the plate when finished.

Physical Activity -- setting up a weekly activity goal, signing a contract to perform the activity with a specific reward for reaching the goal. Family television viewing patterns should be modified as
needed.

Attitude Changes -- teaching the child to turn negative self-statements into positive ones, and helping him or her cope with the negative remarks of others.

Reinforcements and Rewards -- providing verbal praise from family members as well as tangible
rewards for the child's achieving dietary, activity and weight loss goals. Rewards should be deter-
mined with input from the child, and should encourage further physical activity, such as sporting
equipment or a trip to the skating rink.

Family Involvement

It is important to involve the whole family when treating obesity in children. There is a familial
aggregation of risk factors for obesity and the family provides the child's major social learning envi-
ronment. It has been shown that the long-term (10-year) effectiveness of a weight control program is
significantly improved when the intervention is directed at the parents as well as the child, rather
than aimed at the child alone.

*From "Evaluation and Treatment of Childhood Obesity" by Michael Johnson, MD

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