The purpose of this study is to find out how effective lifestyle modification group therapy is on reducing body weight when compared to usual care in individuals with schizophrenia and/or schizoaffective disorder.

Inclusion Criteria:

1. Subjects will be between 18 and 65 years of age.
2. Have a BMI of 28 or greater.
3. Meet DSM-IV criteria for schizophrenia or schizoaffective disorder.
4. Be on a stable dose of antipsychotic medication for at least one month, with positive symptoms stability as judged by the clinical team and investigator.

Exclusion Criteria:

1. A history of dementia or mental retardation.
2. Not capable of giving informed consent for participation in this study.
3. Ongoing pregnancy.
4. Living in a structured environment where the meals are provided as part of the program, e.g., a group home, nursing home, etc.