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.

Put into the child's body the amount of food that exceeds the baby's digestive capacity. A six-month-old baby begins to eat solids if overfeeding the number of meals (2 meals) and the amount of food (100ml), the baby will not have enough digestive enzymes. This portion of food will not be fully absorbed into the body, making the baby full or causing diarrhea, making the baby bloated, indigestion, so refusing to drink milk, digestive disorders and weight gain. In each child's body, the ability to digest and absorb food is different, so the child may eat a lot compared to the same age, but it is too much for children. Therefore, it is necessary to decrease the amount between the amount of food and the amount of milk for the baby to have proper digestion and the best development for the baby.