The goal of this clinical trial is to compare the effect of nutritional counseling versus no treatment in patients with schizophenia or bipolar affective disorder. The main question it aims to answer are: • Can nutritional counseling have a preventive effect on the development of cardiovascular disease in patients with schizophenia or bipolar affective disorder? Participants will meet a nutritionist at baseline to asess nutritional status, biochemical and anthropometric measurements. Then, half of the study population will receive nutritional counseling. After six weeks, the same baseline measurements will be repeated to examine any potential differences between the two groups. After the intervention, the control group will be offered the same counseling as the intervention group received during the study.