Aim: The aim of this review article is to conduct a thorough analysis of scientific publications on the importance of lifestyle, diet, and physical activity in the prevention and rehabilitation of people with chronic diseases. Material and methods: The review article takes into account obesity, type 2 diabetes, and cardiovascular disease due to the high prevalence of these chronic diseases on a global scale. The study is based on a thorough analysis of publications containing up-to-date information on healthy behaviors in people struggling with chronic diseases. The results clearly indicate the positive aspects of leading a healthy lifestyle. It is worth noting that regular exercise, a balanced and nutritious diet, health education, and psychological support have a huge impact on the health of people with chronic diseases. The article also emphasizes the importance of following recommendations, regular check-ups, and appropriate patient motivation under the supervision of medical staff. Conclusions: The review article clearly indicates that the lifestyle of patients with chronic diseases has a significant impact on their quality of life. Prevention and rehabilitation play a key role in reducing the risk of developing chronic diseases or slowing down their progression.