Many vegetarians are motivated by the health aspect of starting a plant-based diet. This diet can offer many health benefits. The study aimed to check whether people on a vegetarian diet are in good health, have a good nutritional intake, and follow the principles of healthy eating compared with omnivores. Twenty-two vegetarians on a vegetarian diet for more than five years and 22 omnivores aged 18–45 were interviewed. Each of them was given a food questionnaire, body composition analysis (BIA), and biochemical blood analysis, and their 7-day diet was analyzed. Polish vegetarians exhibit similar health statuses and tend towards better health than omnivores. They have an adequate body composition. Biochemical blood analysis showed no significant differences in blood parameters between vegetarians and omnivores, despite specific deficiencies such as vitamin B12, vitamin D and elevated homocysteine levels in vegetarians. They have a better nutritional status and follow good dietary principles. However, they were more likely to consume alcohol, add salt to their meals and sweeten hot drinks. In addition, the lifestyle of vegetarians can be described as healthier, as they are more likely to engage in leisure-time physical activity and get enough sleep.