Body mass index (BMI), is a person's weight in kilograms divided by the square of a person's height in meters, or kilograms ÷ (height in meters)2. BMI is the measurement used to define obesity. In adults, we define that a BMI between 25 and 29 is overweight and that a BMI 30 or higher is obese. In children, the normal range for BMI changes with age and gender. The Centers for Disease Control (CDC) defines a child whose BMI is between the 85th and 95th percentile for age (meaning that 85-95% of his or her peers have equal or lower BMI) as being "at risk" for obesity. A child who has a BMI at or above the 95th percentile for age is considered obese.
Currently in the United States, thirty percent of children ages 6-19 years have a BMI at or greater than the 95th percentile. This is double the number that existed 20 years ago. The numbers are even higher in many minority groups, such as African-American, Hispanic and Native Americans. In order to help stem the tide of morbidity and mortality seen in obese adults in our country, we need to start focusing on changing the habits of our youth.
Causes
Research over the past few years has tried to focus on genetic causes of obesity. There has been no discovery of a "fat gene." Like many other diseases, there are many causes of obesity including both genetic and environmental influences. We know that obesity "runs in families," and this is most likely due to the passing down of eating and exercise patterns from parent to child. A child who has one obese parent is three times more likely to be obese as an adult. A child with two obese parents is ten times more likely to be obese later in life.
What has changed in our society in the past few decades to cause such a rise in obesity? First, families spend less time eating meals together. This absence of family meals correlates to lower fruit and vegetable consumption as well as an increased tendency to eat fried food and drink carbonated beverages. Children are often left to fend for themselves at home and look for something that is easy to prepare, inexpensive, and makes them feel full.
Secondly, Americans have become more sedentary. Many physical education programs have been cut in our schools. Parents are now more likely to drive their children to school, either because of safety concerns or because of long distances between school and home. Children spend more time watching TV, surfing the Internet, and playing video games. Increased television viewing not only decreases a child's activity level, but also makes the child more susceptible to advertisers. Research has shown that increased television viewing correlates to decreased fruit and vegetable consumption and higher rates of fast food and fried food intake.
Lastly, school nutrition programs have also been failing. Many schools have vending machines filled with candy bars, desserts, fried foods, and soda. The schools themselves usually serve high-calorie, high-fat meals with no healthy alternatives. Even though many state legislatures and communities are trying to limit the influence that large corporations have in the schools, the schools often depend on the revenue from these snack shops and vending machines.
Effects
As the rates of obesity continue to rise, children are now suffering from diseases that were once thought to only plague adults. High cholesterol, high blood pressure, arthritis, fatty deposits in the liver, and type 2 diabetes are all common findings in overweight children. Type 2 diabetes was formerly known as adult onset diabetes in order to distinguish it from type 1 diabetes, or juvenile onset diabetes. Whereas type 1 diabetes is thought to be an autoimmune disorder that requires daily insulin injections as treatment, type 2 diabetes can be controlled by diet and oral medications during its early stages. Sleep apnea, a disordered breathing pattern which causes decreased oxygen delivery to the brain, can impair a child's ability to concentrate and stay active during the day.
In addition to these diseases, the extra adipose tissue found in overweight prepubescent youths affects their hormonal balance. Girls can develop early onset of their menstrual cycles. Since a girl usually stops growing approximately two years after the onset of her menstrual period, overweight girls may not achieve their full growth potential. Boys can develop breast tissue and can either have early onset or delays in puberty.
Whereas doctors know how to treat the complications of obesity in adults with a variety of medications, the decision is more difficult in children. We lack knowledge about the short-term and long-term side effects of these medications when used in children. Many physicians, therefore, choose to advocate weight loss, which can often reverse these medical problems in children. However, just as with their parents, weight loss is often difficult to achieve.
Treatment Strategies
In order to lose weight, a person must take in fewer calories than he or she uses during the day. Therefore, the key to weight loss is decreasing caloric intake while increasing energy expenditure. Families must change together, since we know children are learning many of their habits in the home. Below are some basic steps to start a healthy, moderate diet plan.
First, initiate an exercise routine, but start off slow. The final goal should be 30 minutes of continuous cardiovascular activity at least 4 times per week. However, this goal may seem daunting, so starting with 15 minutes, and gradually increasing by 5 minutes per week may be an easier task to achieve. Exercise can be walking in the neighborhood or around a track, riding bicycles, hiking, swimming, or using machines at a local gym or YMCA. If all members of the family are included in the routine it is more likely everyone will stay motivated and achieve their goals.
Second, watch portion sizes. Many children ask for second and third helpings of their favorite foods, which lead to overeating. Children are influenced by how their food fills up their plate. If they are given a small plate completely covered by food, they are less likely to ask for more than if they were given a larger plate with the same amount of food.
Third, begin to plan ahead for grocery shopping. Do not buy juice or soda, which provide children with unnecessary calories. Switch from 2% or whole milk to fat free or 1% milk. Limit the amount of chips, cookies and baked goods in the house, so that children will have to turn to more healthy alternatives when they are hungry. Monitor the caloric and fat content of frozen foods. During the week when the family is most busy, parents turn to making frozen dinners for the family. However, many of these easy to prepare meals are equivalent to a meal from a fast-food restaurant.
Fourth, monitor time spent in front of the television and computer. The American Academy of Pediatrics recommends that children and adolescents should not spend more than 2 hours per day watching TV, playing video games or working on the computer. Children will then find more active and creative ways to spend their time.
Finally, use local resources to help keep the family motivated and on track. The pediatrician or family practitioner should evaluate an overweight child at least every 3 months for weight and blood pressure checks. Depending on the age and weight of the child, the goal will sometimes be to maintain weight as the child grows in height, rather than to start losing weight. Screening blood tests for high cholesterol and diabetes should be performed on a regular basis, as well as checking in with how the child is dealing emotionally with the change in lifestyle.
