A fast - paced lifestyle, mostly sedentary jobs, inadequate nutrition. All of these are the reasons why an increasing number of people have excessive body weight and numerous diseases. These are precisely some of the reasons why individuals decide to engage in some form of recreation activity and decide to pay attention to their diet. In this paper we will deal more in detail why is balancing our diet and physical activity so important. The paper is conceived in several parts. In the first chapter, the focus is on a concrete represetnation of the subject and goal of the work itslef, the research methods used within the work, as well as a representation of the structure of the work. The second chapter refers to physical activity in general. Within this chapter, we will define the term of physical activity, the specific contribution of recreation and fitness to physical health, as well as the importance of sport in everyday life. Furthermore, the third chapter deals with the topic of nutrition, its relevance and impact on human health. Within this chapter, we will touch on more in details on proteins, carbohydrates, fats, vitamins and minerals and explain their essential importance for humans. The body hidration and importance of water will be mentioned as well. Following on from the third chapter, the fourth chapter elaborates the impact of nutrition in the field of recreation and fitness in a way that explains the importance of nutrition in regulation of body mass, in imporoving performance, but also in recovery after excercize. At the end of thessis there is a conclusion based on this work.