For underweight individuals, the achievement of a low normal weight is a priority for further treatment to be successful. Such treatments involve both behavioural monitoring and nutritional rehabilitation with the aim to normalise the individual’s weight. Psychotherapy treatment will focus on correcting the irrational preoccupations with both weight and body shape, and in preventing any relapse to previous damaging behaviours.
Practical interventions would involve careful monitoring of weight gain, and prescribing an adequate diet. Failure to achieve these might lead to inpatient hospitalisation (see question: Might inpatient treatment be necessary?).