Psoriasis is an autoimmune disease characterized by inflamed skin areas, scales and itching. Certain foods can create an environment in the body that promotes the development of chronic diseases like psoriasis by triggering the inflammatory process. A change in diet can have a very positive effect on the course of the disease, but presents a challenge for those affected. The importance of this problem leads to the investigation of how interaction with technological devices can promote long-term behavioural change. Based on the theoretical foundations of behavioural psychology, the prototype mobile application «Flaky» was developed. «Flaky» supports psoriasis sufferers in their dietary changes by informing and motivating them to heal their skin naturally.