How do I check whether I'm underweight or not?

While the criteria for being overweight are very well defined, those for being underweight vary from region to region. Clinicians find it more appropriate to use the word "malnourished". The following conditions may signify an individual as being malnourished-

• Body mass index (BMI) less than 18.5
• Weight less than two standard deviations below the national standard
• Weight less than 80% of median standard weight
• Low serum albumin levels on laboratory testing
• Low serum transferrin levels
• Recent loss of body weight (more than 10%body weight lost within 2 months signifies especially poor outcome)
• Anemia
• Other signs of malnutrition on clinical examination by a doctor.

This is only a very general information. Wherever doubt arises, it must be clarified by consulting a medical doctor. For the statistics, please check with the official health website of your country's government for details.