Diet and physical activity interventions are effective in psychiatric outpatients that suffer from obesity, namely those treated with antipsychotic drugs. However, there is less evidence related to these interventions in hospitalised acute patients.

To evaluate the effect of a diet and physical activity program on weight and BMI variation in acute psychiatric patients during hospitalisation.

Matched case-control study from January to September 2016. Inclusion criteria: patients with at least 15 days of hospitalisation in an acute psychiatry ward, evaluated by a nutritionist in the admission and medical discharge. The intervention consisted in a diet and physical activity program, with total restriction to visitors to bring food to the patients. Statistical analysis was done with T-student and multiple linear regression taking into account the effect of age, sex, daily dose of antipsychotics, and days of hospitalisation.

Sixty-six patients were studied (34 cases and 32 controls). Groups were statistically similar concerning the average of age, daily dose of antipsychotics, days of hospitalisation and sex. The differences of weight gain during hospitalisation were 0.088 kg (cases) versus 1484 kg (controls), P < 0.05. And the differences of the increased BMI during the hospitalisation were 0.041 kg/m2 (cases) versus 0.509 kg/m2 (controls), P < 0.05.

Obesity presents challenging health problems for individuals with severe mental illness that require inpatient treatment. This study provides evidence that individuals with acute mental illness can benefit from weight control interventions during their hospitalisation, in special a total restriction to visitors to bring food to the patients.