Underweight is defined as the proportion of children whose weight in relation to their age is below −2 standard deviations (−2 z scores) of the median of the National Center for Health Statistics (NCHS) reference.

What is underweight according to who?

Underweight is defined as low weight-for-age. A child who is underweight may be stunted, wasted or both. Micronutrient deficiencies are a lack of vitamins and minerals that are essential for body functions such as producing enzymes, hormones and other substances needed for growth and development.

What is considered skinny?

What exactly counts as being “skinny?” Some healthcare experts believe a BMI in the 15-18 range to be clinically underweight. This seems to fall pretty close to what many everyday people consider to be “skinny” with a BMI of 18 or lower frequently listed as the indicator of someone considered to be slim.