Dr Preuss has investigated mechanisms of circadian regulation from flies, over mice to humans. Those studies involved the investigation of circadian and sleep disorders or disruptions and the effects on the physiology of the organism. The most recent and current studies involve the elucidation of links between the circadian system and body responses to dietary or pathological challenges in cancer mice. In parallel, he investigates the effects of desynchronized feeding and the effects of fibers on rhythms and the mircobiota.