When children eat more food than their bodies need for normal growth and activity, the extra calories are stored in fat cells for later use. If this pattern continues over time, they develop more fat cells and may develop obesity.
Normally, infants and young children respond to signals of hunger and fullness so that they do not consume more calories than their bodies need. However, changes over the last few decades in lifestyle and food choices have led to the rise of obesity among children.
Children are surrounded by many things that make it easy to overeat and harder to be active. Foods that are high in fat and sugar content often come in large portion sizes. These factors can lead children to take in more calories than they need before they feel full. TV commercials and other screen ads can lead to unhealthy food choices. Most of the time, the food in ads aimed at kids is high in sugar, salt, or fats.
"Screen time" activities such as watching television, gaming, texting, and playing on the computer require very little energy. They often take the place of healthy physical exercise. Also, children tend to crave unhealthy snack foods they see in TV ads.
Other factors in the child’s environment can also lead to obesity. Family, friends, and school setting help shape a child’s diet and exercise choices. Food may be used as a reward or to comfort a child. These learned habits can lead to overeating. Many people have a hard time breaking these habits later in life.
Genetics, medical conditions, and emotional disorders can also increase a child’s risk for obesity. Hormone disorders or low thyroid function, and certain medications, such as steroids or anti-seizure medications, can increase a child's appetite. Over time, this increases their risk for obesity.
An unhealthy focus on eating, weight and body image can lead to an eating disorder. Obesity and eating disorders often occur at the same time in teenage girls and young adult women who may be unhappy with their body image.