The aim of the study was to describe mental health staff experiences of giving support to prevent type 2 diabetes mellitus (DM) among people with psychosis in community psychiatry. A qualitative interview study with a purposeful sample of 12 community health staff was conducted. Data were analysed using qualitative content analysis. The results show how staff reported continuously supporting people with psychosis to adapt to healthy lifestyles, but stated that support is not given until after a person becomes overweight or is diagnosed with type 2 DM. Support was described as a never‐ending process of motivation facing many reverses. Individually‐adapted support given in practical situations was perceived as most successful. Cooperation between health‐care organizations was seen as essential, but inadequate. Limitations in income and social network, and easy access to fast food and alcohol, were seen as obstacles to support. The results indicate that community health staff are in a position to make a considerable impact in motivating and supporting healthy lifestyle changes in practical situations in daily life among people with psychosis. This study raises awareness of how community health staff's support can be useful when developing nursing skills and health‐care plans for people with psychosis.