Labor provides an overview of the content of vegan and vegetarian diets and their sufficiency for engaging in demanding physical activity, i.e. amateur and professional sports. It describes the forms of vegetarianism that are encountered and exist in today's developed form of the food industry. Thus, certain forms differ in small amounts from the daily diet, while some require a special dedication to the diet regime in addition to the already exhausting demands of playing sports. The history of the origin of vegetarianism is touched upon, described through scarce and insufficiently based sources from history. The paper states what every athlete should take into his body during his activities and how he needs his rest for progress. How to nutritionally prepare for training or recover after it, which means a lot to him for long-term work during his sports career until the achievement of results. It specifically focuses on vegetarian forms of nutrition for athletes, listing possible nutrients that could be lacking in these forms of nutrition - which sources are good for the intake of certain nutrients, what could be affected, as well as the recommended amounts for sports. With an insufficient number of studies, especially long-term ones, the approximate numbers of athletes on a vegetarian or vegan diet are listed. Health is certainly the first item in the athlete's motivation for vegetarianism, its lack halts the athlete's progress or ends the athlete's career, which means everything to professional athletes. Some of them are mentioned in this paper, as well as the results they achieved with a vegetarian diet, which shows the possibility for others to follow them without fear if they want to avoid consuming large amounts of meat, which can be harmful for the body, according to numerous studies.