BackgroundObesity is a prevalent health problem in patients with schizophrenia, and calorie restriction diet (CRD) achieved effective weight loss and metabolic improvement; however, these have not been rigorously evaluated in obese patients with schizophrenia.ObjectiveTo measure the effects of CRD on weight loss and metabolic status in hospitalized obese women with schizophrenia during a 4-week period.MethodsParticipants were randomly assigned to two groups in a 1:1 ratio. The intervention group (n= 47) was asked to follow a CRD and the control group (n= 48) a normal diet for 4 weeks. Outcomes of body weight, body composition, as well as metabolic parameters were measured at baseline and following the intervention period.ResultsForty-five participants completed the 4-week research in both the intervention and control groups. Compared to the normal diet, adherence to the CRD significantly decreased body weight (2.38 ± 1.30 kg), body mass index (0.94 ± 0.52 kg/m2), waist circumference (4.34 ± 2.75 cm), hip circumference (3.37 ± 2.36 cm), mid-upper circumferences, triceps skin-fold thickness, fat mass and free fat mass with large effect sizes (p= <0.001,ηp2range between 0.145 and 0.571), as well as total cholesterol (0.69 ± 0.70 mmol/L) with a medium effect size (p= 0.028,ηp2= 0.054). There were no differences between the CRD and control groups in terms of pre-post changes in triglycerides, high- and low-density lipoprotein-cholesterols, as well as systolic and diastolic blood pressures (p> 0.05).ConclusionCRD is preventative of weight gain, but not apparent in intervention for metabolic status in hospitalized obese women with schizophrenia.Clinical trial registration:http://www.chictr.org.cn, ChiCTR-INR-16009185.