If a person with anorexia needs professional help, but is usually unwilling to seek it, see a doctor to find out the best approach.
Remember that even though anorexia is a dangerous illness, it gives a person a sense of being able to control overwhelming feelings. Someone who has anorexia will struggle against giving up this control, even if this means begging and lying. It is important for family and friends not to give in to this manipulation -- but constant nagging won't help, either. People can't get over anorexia just by changing their minds. They need professional help.