Background: Prevalence of obesity in schizophrenic patients is two to thret, times higher than in the general population and unhealthy dietary patterns, a sedentary lifestyle and antipsychotic medication use may contribute to the higher levels of obesity among schizophrenic patients. Aims: We evaluated the effects of diet therapy on weight loss, anthropometric and biochemical variables in overweight or obese (body mass index, BMI27 kg/m2) female schizophrenic patients who use antipsychotic medications and in healthy volunteers. Methods: Primary demographic variables were collected via questionnaire; blood samples and anthropometric measurements were obtained. Personalized diet recipes were prepared and nutritional education was shared. We logged the physical activity of the patients and maintained food consumption records at 3-day intervals. Participants were weighed every week; anthropometric mea.surements and blood samples were collected at the end of the first and second months. Results: At the end of the study, reductions in body weight and other anthropometric measurements were statistically significant (P<0.05). Reductions in body weight and BMI values for patient group were -4.05 +/- 1.73 kg and -1.62 +/- 0.73 kg/m(2) and for the control group were -6.79 +/- 1.80 kg and -2.55 +/- 0.64 kg/m(2), respectively. When compared with the patient group, reductions in the anthropometric variables of the control group were statistically significant (P<0.05). Fasting glucose, blood lipids, albumin and leptin levels were decreased; insulin and homeostatic model assessment-measured insulin resistance (tOMA-IR) levels were increased insignificantly. Increases in the blood ghrelin levels for both groups were statistically significant (P<0.05). Conclusions: Improvements to the diets of schizophrenic patient led to improvements in anthropometric measurements and biochemical variables and reduced the health risks caused by antipsychotic medications. Furthermore, we hypothesize that antipsychotic medications do not have any direct effect on leptin and ghrelin metabolism, and that changes in hormone metabolism may be attributable to changes in body weight.