Underweight

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics

Underweight
Synonyms	Low body weight
Pronounce	N/A
Specialty	N/A
Symptoms	Fatigue, dizziness, hair loss, amenorrhea
Complications	Malnutrition, osteoporosis, infertility, immune dysfunction
Onset	Any age
Duration	Variable
Types	N/A
Causes	Malnutrition, eating disorders, chronic disease, genetic factors
Risks	Anemia, heart problems, reduced muscle strength
Diagnosis	BMI < 18.5
Differential diagnosis	Hyperthyroidism, celiac disease, cancer, tuberculosis
Prevention	Balanced diet, regular health check-ups
Treatment	Nutritional support, addressing underlying conditions
Medication	Nutritional supplements
Prognosis	Variable, depending on cause
Frequency	Varies by population
Deaths	Rare, but possible due to complications

An overview of underweight and its implications on health.

Underweight is a condition where an individual has a body weight considered too low to be healthy. It is often defined using the Body Mass Index (BMI), a measure that compares weight to height. A BMI below 18.5 is typically classified as underweight.

Causes

There are several potential causes of being underweight, including:

• Malnutrition: Inadequate intake of nutrients can lead to underweight.
• Metabolic disorders: Conditions like hyperthyroidism can increase metabolism and lead to weight loss.
• Chronic diseases: Diseases such as cancer, tuberculosis, and HIV/AIDS can cause weight loss.
• Eating disorders: Disorders like anorexia nervosa and bulimia nervosa can result in being underweight.
• Genetics: Some individuals may naturally have a lower body weight due to genetic factors.

Health Implications

Being underweight can have several health implications, including:

• Immune system: A weakened immune system, making one more susceptible to infections.
• Osteoporosis: Increased risk of bone fractures due to low bone density.
• Anemia: A deficiency in red blood cells or hemoglobin.
• Fertility issues: Potential problems with fertility and pregnancy.
• Growth and development: In children and adolescents, underweight can affect growth and development.

Diagnosis

Diagnosis of underweight typically involves calculating the Body Mass Index and assessing dietary intake, medical history, and physical examination. Additional tests may be conducted to identify underlying causes.

Management

Management of underweight involves addressing the underlying cause and may include:

• Nutritional support: Increasing caloric intake with a balanced diet.
• Medical treatment: Treating any underlying medical conditions.
• Psychological support: Counseling for those with eating disorders.

Prevention

Preventing underweight involves ensuring adequate nutrition and addressing any medical or psychological issues that may contribute to weight loss.

See also

• Body Mass Index
• Malnutrition
• Eating disorders
• Metabolic disorders