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.