Underweight
A person's body weight being significantly below normal for their given age and height; in adults, this may be calculated as a BMI under 18.5 (using online calculators) in adults or using growth charts for children.
An underweight person is the type of person whose body weight is considered too low to be healthy. Underweight people have a body mass index (BMI) of under 18.5 or a weight of 15% to 20% below that normal for their age and height group.
A person may be underweight due to genetics, metabolism, drug use, lack of food (frequently due to poverty), eating disorder, or illness (both physical and mental).
Being underweight is associated with certain medical conditions, including anorexia, type 1 diabetes, hyperthyroidism, cancer, or tuberculosis. People with gastrointestinal or liver problems may be unable to absorb nutrients adequately. People with certain eating disorders can also be underweight due to a lack of nutrients/over-exercise.
Treatment for underweight will rely upon the cause or symptoms you're experiencing, so your medical consultant will determine treatment options based on the cause.
