What's Anorexia Nervosa, eating disorder that killed Kerala girl?

An 18-year-old girl in Kerala died due to anorexia nervosa. According to UK's NHS, Anorexia nervosa is an eating disorder and serious mental health condition. People who've anorexia often have a distorted image of their bodies, thinking they are fat even when they're underweight. The girl had reportedly avoided proper food for nearly six months, surviving only on hot water.