A chronic disease defined as having an excess of body fat. Body mass index (BMI), which is defined as weight in kilograms divided by height in meters squared, is accepted as a proxy measurement of adiposity in children.

• Children <2 years of age:
  Weight for length >95% for age: Obese
• Children >2 years of age:
  • BMI <5%: Underweight
  • BMI 5–85%: Normal weight
  • BMI 85–95%: Overweight
  • BMI >95%: Obese
  • BMI 95–99%: Obese
  • BMI >99%: Morbid obesity