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Childhood obesity is the condition of being overweight or severely overweight which causes risks to health between the ages of 2 and 19.
(Illustration by GGS Information Services/Thomson Gale.)
Childhood obesity is of increasing concern as a public health problem in the United States. Overweight and obesity are defined by most healthcare professionals using the Body Mass Index (BMI). BMI is a calculation that compares a person’s weight and height to arrive at a specific number. For details of how to calculate BMI see the body mass index entry.
Children between the ages of 2 and 19 are assigned a percentile based on their BMI number. The percentile tells them how their weight compares to that of other children who are their same age and gender. For example, if a boy is in the 65th percentile for his age group, 65 of every 100 children who are his age weigh less than he does and 35 of every 100 weigh more than he does. Adult BMI is interpreted differently.
The BMI weight categories for children are:
- Below the 5th percentile: Underweight
- 5th percentile to less than the 85th percentile: Healthy weight
- 85th percentile to less than the 95th percentile: At risk of overweight
- 95th percentile and above: Overweight
There is some debate about what to call children who are in the at risk for overweight and overweight categories. Some healthcare organizations such as the American Obesity Association use the term overweight for those at or above the 85th percentile and obese for those at or above the 95th percentile. The National Institutes of Health prefers to avoid applying the term obese to children, in part because of the social stigma the word carries. Whatever term is used to describe children in the top 15th percentile, these.
There is no doubt that American children are getting heavier, and although the problem of overweight is growing fastest in the United States, the trend toward heavier children is occurring in most in most developed countries. In the United States, the National Center for Health Statistics has tracked children’s weight for several decades and recorded the following changes in the percent of children who are overweight (above the 85th percentile):
- Children ages 2–5: 1971–74 5% 1988–94 7.2% 2003–04 13.9%
- Children ages 6–11: 1971–74 4% 1988–94 11.3% 2003–04 18.8%
- Children ages 12–19: 1971–74 6.1% 1988–94 10.5% 2003–04 17.4%
In terms of numbers, this means that 12.5 million children were overweight in 2003-04. During the same time, 32.2% of adults, or 66 million people, were obese. Other surveys have found the total obesity rate among children and adolescents to be between 21% and 24%.
Significant differences exist in the number of children who are overweight in different races and ethnic groups, and these mirror the differences in the adult population. Significantly more Mexican American boys are overweight than non-Hispanic black or white boys. Significantly more Mexican American girls and non-Hispanic black girls are overweight than white girls. Native Americans and Hawaiians also have higher rates of overweight than whites.
At its simplest, overweight is caused by taking in more calories than the body uses. This difference is
called the “energy gap.” A 2006 study done by the Harvard School of Public Health and published in the journal Pediatrics found that, on average, American children consumed between 110 and 165 extra calories than they use up every day. Over a 10-year period, these extra calories would add 10 lbs to their weight. However, already overweight teens took in an average of 700-1,000 extra calories every day, resulting in an average of 58 extra pounds.
There are many reasons why the energy gap exists, these reasons are related to both increased food intake and decreased energy use. Food intake reasons include:
- increased consumption of sugary beverages, and along with this, a decreased consumption of milk
- tendency to super-size portions. In some fast food restaurants portions have almost tripled since the 1970s.
- more meals eaten away from home
- more use of prepared foods in the home
- increased snacking between meals along with fewer meals eaten together as a family
- heavy advertising of high-sugar, high-fat foods to children
- decrease in children carrying their lunch to school from home
- poor eating habits such as skipping breakfast and later snacking on high fat, sugary foods
Inadequate energy use reasons include:
- more time spent watching television or using the computer.
- fewer physical education requirements at school. According to the Centers for Disease Control, in 2000, only 8% of elementary schools, 6.4% of middle schools, and 5.8% of high school required daily physical education classes.
- fewer children walking to school. In 1969 half of all school children walked or biked to school. The rate was 87% for children living within 1 mile of their school. In 2003, only 15% of children walked or biked to school
- decreased recess in grades 1-5. More than 28% of schools do not provide a regularly scheduled recess in these grades.
- fear of crime, which limits outdoor activities of children
- more affluence. Teen access to cars has increased over the past 30 years.
Other factors that affect childhood obesity include an inherited tendency toward weight gain, mental illness, binge eating disorder, and eating in response to stress, boredom, and loneliness, poor sleeping habits, and having at least one obese parent.
In rare cases, medical or genetic disorders can cause obesity. For example, Prader-Willi syndrome is a genetic disorder that causes an uncontrollable urge to eat. The only way to prevent a person with Prader-Willi disorder from constant eating is to keep them in an environment where they have no free access to food. Other genetic and hormonal disorders (e.g. hypothyroidism) can cause obesity. Certain medications also can cause weight gain (e.g. cortisone, tri-cyclic antidepressants), but these situations are the exception. Most children are too heavy because they eat to much and/or exercise too little.
The most obvious symptom of obesity is an accumulation of body fat. Other symptoms involve changes in body chemistry. Some of these changes cause disease in children, while others put the child at risk for developing health problems later in life. Children who are overweight are at increased risk of:
- type 2 diabetes. This disease is appearing in children and young adults at an alarmingly high rate. In the past, it was usually seen in older adults.
- high blood pressure (hypertension)
- fat accumulation in the liver (fatty liver/liver disease)
- sleep apnea
- early puberty; early start of menstruation in girls
- eating disorders
- joint pain
- increased anxiety and stress
- low self-worth
- exposure to social prejudice and discrimination
Diagnosis is usually made on the basis of the child’s BMI. To better assess the problem, the physician will take a family history and a medical history and do a complete physical examination, including standard blood and urine tests. A thyroid hormone test may be done to rule out hypothyroidism as the cause of obesity. Based on the physician’s findings, other tests may be performed to rule medical causes of obesity.
Overweight children and their parents may be referred to a registered dietician or nutritionist who can help them develop a plan for eliminating empty calories and increasing the amount of nutrient-rich, low-calorie foods in their diets. Nutrition education usually involves the entire family. Children may be asked to keep a food diary to record everything that they eat in order to determine what changes in behavior and diet need to be made. Typically, children are encouraged to increase their level of exercise rather than to drastically reduce calories.
Drug therapy and weight-loss surgery are very rarely used in children, except in the most extreme cases of health-threatening obesity when other methods of weight control have failed. Some teenagers benefit from joining a structured weight-loss program such as Weight Watchers or Jenny Craig. They should check with their physician before joining.
Teaching children how to eat a healthy diet sets a framework for their lifetime eating habits. A nutritionist or dietitian can help families to understand how much and what kinds of food are appropriate for their child’s age, weight, and activity level.
The American Heart Association has adapted the following dietary suggestions from the federal Dietary Guidelines for Americans 2005. These guidelines apply to people over age 2. Separate guidelines exist for infant nutrition.
- For children ages 2–3, no more than 35% of their calories should come from fats.
- Children over age 3 should limit their fat intake to about 30% of their total calories. These fats should be monounsaturated or polyunsaturated. Saturated fats and trans fats should be avoided.
- Fruit and vegetable intake should be increased, but fruit juice should be limited.
- At least half of all grains eaten should be whole grains.
- Sugary drinks, such as carbonated soft drinks, should be extremely restricted.
- Dairy products should be fat-free or low fat after age 2. Before age 2 children need milk fats for proper growth and development of the nervous system.
- A variety of foods should be offered children, including fish and shellfish.
- Overfeeding children or making them “clean their plates.” should be avoided.
It is often difficult for parents to understand how much food their child should eat at a particular age. Parents tend to overestimate the amount of food small children need. The daily amounts of some common foods that meet the American Heart Association guidelines for different ages are listed below. These amounts are based on children who are sedentary or physically inactive. Active children will need more calories and slightly larger amounts of food.
- children age 2–3 years: Total daily calories 1,000; milk 2 cups; lean meat or beans 2 ounces, fruits 1 cup; vegetables 1 cup; grains 3 ounces.
- girls ages 4–8 years: Total daily calories 1,200; milk 2 cups; lean meat or beans 3 ounces; fruits 1.5 cups; vegetables 1 cups; grains 4 ounces.
- boys ages 4–8 years: Total daily calories 1,400; milk 2 cups; lean meat or beans 4 ounces, fruits 1.5 cup; vegetables 1.5 cups; grains 5 ounces.
- girls ages 9–13 years: Total daily calories 1,600; milk 3 cups; lean meat or beans 5 ounces, fruits 1.5 cups; vegetables 2 cups; grains 5 ounces.
- boys ages 9–13 years: Total daily calories 1,800; milk 3 cups; lean meat or beans 5 ounces, fruits 1.5 cups; vegetables 2.5 cups; grains 6 ounces.
- girls ages 14–18 years: Total daily calories 1,800; milk 3 cups; lean meat or beans 5 ounces, fruits 1.5 cups; vegetables 2.5 cups; grains 6 ounces.
- boys ages 14–18 years Total daily calories 2,200; milk 3 cups; lean meat or beans 6 ounces, fruits 2 cups; vegetables 3 cups; grains 7 ounces.
Children who are overweight often have psychological and social problems that can be helped with psychotherapy in addition to nutritional counseling.
- Cognitive behavior therapy (CBT) is designed to confront and then change the individual’s thoughts and feelings about his or her body and behaviors toward food, but it does not address why those thoughts or feelings exist. Strategies to maintain self-control may be explored. This therapy is relatively short-term.
- Family therapy may help children who eat for emotional reasons related to conflict within the family. Family therapy teaches strategies to reduce conflict, disorder, and stress that may be factors in triggering emotional eating.
The younger the child is when weight control strategies begin, the better the chance that the child will be able to maintain a normal weight. When it comes to weight control, one advantage children over adults is that they grow. If a child can maintain his weight without gaining, he may grow into a normal weight as he becomes taller. Parents need to be careful about how they approach weight loss in children. Critical comments about weight from parents or excess zeal in putting their child on a rigorous diet can trigger eating disorders such as anorexia nervosa or bulimia nervosa in some children, especially adolescent girls.
Children who remain overweight have a much greater likelihood of being overweight adults with all the health problems that obesity brings. Studies have found that 26–41%of preschoolers who are obese become obese adults. In school-aged children, 42–63% of children with obesity become obese adults. The greater the degree of overweight, the higher the likelihood that overweight will continue into adulthood.
Parents must take the lead in preventing obesity in children. Some of the ways they can do this are:
- Serve a healthy variety of foods; keep healthy snacks on hand.
- Choose low-fat cooking methods such as broiling or baking.
- Eliminate junk snack food and sugary beverages from the house. This removes temptation and eliminates the need to nag.
- Eat meals together as a family rather than grabbing something quick on the run.
- Limit visits to fast-food restaurants.
- Limit television and computer time.
- Plan family activities that involve physical activity, such as hiking, biking, or swimming.
- Encourage children to become more active in small ways such as walking to school, biking to friends” houses, or doing chores such as waking the dog or mowing the lawn.
- Avoid using food as a reward.
- Pack healthy homemade lunches on school days.
- Encourage school officials to eliminate soda machines on campus, bake sales, and fundraising with candy and cookies
- Set realistic goals for weight control and reward children”s efforts.
- Model the eating behaviors and active lifestyle you would like your child adopt.
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Tish Davidson, A.M.