The basic idea of this thesis are dietary supplements and their increasing use as meal replacements. The Croatian market is flooded with daily information from various media about nutritional supplements that are desirable for health, that is, that can stop natural aging. The idea of replacing natural food with nutritional supplements began at the beginning of the last century and encompasses the understanding of human nutrition and consciousness within the framework of food processing technology, which loses important ingredients necessary for the human body. Questions that arose throughout history were related to how to replace lost nutrients. The trend shows that in the last decade, an increasingly large and diverse range of food supplements that are sold over the counter have appeared on the Croatian market. How the use of supplements will affect human health and what consequences it will have for society and the entire planet has yet to be determined, as research in this field is minimal. In particular, the topic of dietary supplements is the most researched in the USA and is not encouraging, it speaks more about the harm to health and illegal additives that are still found in dietary supplements even after the regulatory ban. The thesis initially presents a theoretical overview of dietary supplements throughout history up to their understanding in the modern age, and at the end of the thesis, an analysis of the conducted research on the use of dietary supplements in the adult population of the City of Zagreb was given. 120 residents of the City of Zagreb between the ages of 20 and 66 directly participated in the research conducted in the Shopping Centers of the City of Zagreb. Data collection was done in the field, through direct contact with respondents, as the goal was to obtain objective data and opinions of respondents, their behavior, and habits. The conducted research confirmed the hypothesis that the majority of the population has a tendency to take nutritional supplements, with the fact that there are deviations in the tendency to take supplements depending on gender, education and other set characteristics of the respondents. Thus, young people and university-educated people tend to take nutritional supplements, while women have a greater tendency to consult with experts before making a decision about taking nutritional supplements, compared to men. There is no similar research conducted in Croatia so the research conducted within the framework of this thesis cannot be compared with other research, however, it can be said that the conducted research will contribute to the understanding of the habits of the population related to taking nutritional supplements.