Pediatric and Adolescent Abnormal Weight Gain

Abnormal weight gain can occur due to several medical conditions, side effects of medication, or physical and lifestyle changes.

Medical conditions

• Asthma and allergies – Breathing difficulties can make it harder for children to be active, leading to weight gain.
• Cushing syndrome – Occurs when the body produces too much of the hormone cortisol. Weight gain typically occurs around the face, midsection, shoulders and upper back.
• Depression – Children with depression can gain weight due to loss of interest in activities.
• Growth hormone (GH) deficiency – A medical condition that causes not enough growth hormone to be present in the body. In addition to weight gain, there can be more fat deposits around the face and stomach areas.
• Hypothyroidism – With this condition, the thyroid gland doesn’t produce enough of the thyroid hormone. This can affect a child’s metabolism and lead to weight gain. 
• Insulinoma –  Occurs when a pancreatic tumor produces excessive amounts of insulin. Children typically gain weight while consuming additional calories to help stabilize blood sugar levels, but they are unable to exercise due to rapid drops in blood sugar.
• Leptin resistance – The leptin hormone is produced by the body's fat cells. It tells the brain when there’s enough fat stored and regulates energy balance. Leptin resistance occurs when the brain no longer recognizes the leptin's function and thinks the body is starving.
• Prader-Willi syndrome – This genetic disorder can cause constant hunger, leading to obesity.

Side effects of medication

• Antidepressants – While the exact cause is unknown, there are several theories as to why weight gain is caused, including metabolic influences that result in cravings and increased appetite.
• Antihistamines – Histamine (chemicals in the body that respond to an infection or allergy) causes reduced appetites. While specific effects are unknown, antihistamines can have an opposite effect, increasing appetite and leading to weight gain.
• Anti-seizure medications – Some anti-seizure medications have been shown to cause weight gain as appetite and energy levels change.
• Oral steroids – Side effects from steroid medications include insomnia, increased appetite and water retention, all of which can lead to weight gain.

Physical and lifestyle changes

• Activity levels – One of the largest contributors to a weight imbalance is a drastic decrease in activity levels while there is an increase in food consumption. The American Health Association recommends all children age 2 and older should have at least 60 minutes of moderate-intensity physical activity each day.
• Gut health – The human body needs the appropriate balance of microbes (gut flora) in the stomach in order to properly function and maintain a healthy weight.
• Puberty – Increased hormones in a child’s body during puberty (between the ages of 10 and 14 for girls and between the ages of 12 and 16 for boys) leads to growth and possible expansion of “baby fat” areas. This typically takes place in girls’ belly, breast area and hips. Boys’ shoulders will get broader.