Definition of Underweight

While being overweight is unhealthy, being underweight can do more damage to the body, according to the University of Mississippi's Medical Center. A higher percentage of people who are underweight suffer from high blood pressure than people who are slightly overweight.

Requirements

• The term underweight applies to those who have a body mass index of less than 18.5 or who weigh 10 percent less than their ideal weight.

Causes

• Causes of being underweight include malnutrition, overexercising, using stimulant drugs, eating disorders, anxiety disorders, disease and heredity.

Effects

• Being underweight leads to mental and physical fatigue, a dulled external appearance, an inability to fight off infectious diseases and infertility.

Warning

• The effects of being underweight can cause heart damage, bone loss and severe mood swings or depression. Consult a doctor for ways to increase weight in a healthy manner.

Prevention

• Eat a well-balanced diet, take vitamin and mineral supplements and get cardiovascular exercise three to five times per week to maintain a healthy weight.