Anorexia is an eating disorder characterized by a severe fear of gaining weight, a distorted body image, and excessive dieting that leads to weight significantly lower than what is considered healthy. People with anorexia restrict their food intake, have a strong desire to be thin, and may exhibit other symptoms like loss of menstrual periods, feeling cold, and losing hair. Treatment focuses on psychotherapy, addressing low self-esteem, family support, and developing a healthy attitude towards eating.