context: One third of children in the U. S. is overweight or obese, and this number is continuing to rise. Children have fewer weight-related health and medical problems than adults. However, overweight children are at high risk of becoming overweight adolescents and adults, placing them at risk of developing chronic diseases such as heart disease and diabetes later in life. They are also more prone to develop stress, sadness, and low self-esteem. Children become overweight and obese for a variety of reasons. The most common causes are genetic factors, lack of physical activity, unhealthy eating patterns, or a combination of these factors. Only in rare cases is being overweight caused by a medical condition such as a hormonal problem. A physical exam and some blood tests can rule out the possibility of a medical condition as the cause for obesity. Although weight problems run in families, not all children with a family history of obesity will be overweight. Children whose parents or brothers or sisters are overweight may be at an increased risk of becoming overweight themselves, but this can be linked to shared family behaviors such as eating and activity habits. A child's total diet and activity level play an important role in determining a child's weight. Today, many children spend a lot time being inactive. For example, the average child spends approximately four hours each day watching television. As computers and video games become increasingly popular, the number of hours of inactivity may increase. Obese children are at risk for a number of conditions, including: High cholesterol High blood pressure Early heart disease Diabetes Bone problems Skin conditions such as heat rash, fungal infections, and acne The best person to determine whether or not your child is overweight is your child's doctor. In determining whether or not your child is overweight, the doctor will measure your child's weight and height and compute his '' BMI,'' or body mass index, to compare this value to standard values. The doctor will also consider your child's age and growth patterns. If you have an overweight child, it is very important that you allow him or her to know that you will be supportive. Children's feelings about themselves often are based on their parents' feelings about them, and if you accept your children at any weight, they will be more likely to feel good about themselves. It is also important to talk to your children about their weight, allowing them to share their concerns with you. It is not recommended that parents set children apart because of their weight. Instead, parents should focus on gradually changing their family's physical activity and eating habits. By involving the entire family, everyone is taught healthful habits and the overweight child does not feel singled out. There are many ways to involve the entire family in healthy habits, but increasing the family's physical activity is especially important. Some ways to accomplish this include: Lead by example. If your children see that you are physically active and having fun, they are more likely to be active and stay active for the rest of their lives. Plan family activities that provide everyone with exercise, like walking, biking, or swimming. Be sensitive to your child's needs. Overweight children may feel uncomfortable about participating in certain activities. It is important to help your child find physical activities that they enjoy and that aren't embarrassing or too difficult. Make an effort to reduce the amount of time you and your family spend in sedentary activities, such as watching TV or playing video games. Whatever approach parents choose to take regarding an overweight child, the purpose is not to make physical activity and following a healthy diet a chore, but to make the most of the opportunities you and your family have to be active and healthy.