Introduction. Efforts to reduce obesity through diet, exercise, education or the use of few drugs, so far, have not been able to solve the problem effectively and to a long-term extent. However, they constitute the basis of contemporary activities in this area. Aim. The aim of the study was to review and analyse the literature in terms of selected factors related to obesity in adults. The relationship between obesity and genetic factors, metabolic syndrome, vitamin D and afamine was presented. The literature review method was used. The literature was overviewed on the grounds of data contained in the GBL database, PubMed, Google Scholar and information available on websites. Results. The knowledge of the carrier state of polymorphisms and gene mutations predisposing to obesity, knowledge of vitamin D supplementation and knowledge of new biochemical research on obesity can contribute to more effective prevention and treatment of obesity and the related diseases. In preventing the formation of metabolic syndrome and its complications, the vital and recurring factors are a lifestyle change and diet modification, increase in physical activity and weight reduction. Conclusions. Obesity is a growing problem in highly developed societies. Therefore, new ways to combat the problem, as well as new ways to prevent dangerous complications such as metabolic syndrome, type II diabetes mellitus or cardiovascular diseases are being explored.

Key words: obesity, metabolic syndrome, genetic factors, vitamin D, afamine.