Although there is no concrete evidence regarding certain nutritional factors that can reduce the risk of COVID-19, the Harvard TH Chan School of Public Health has presented a new guide to maintaining a healthy lifestyle in order to maintain the immune system. Research has shown that people who follow five key habits (healthy diet, regular exercise, maintaining a healthy weight, limited alcohol intake and avoiding smoking) live more than a decade longer than those who do not. In addition, maintaining these habits will not only help us live longer, but also better. Adults who follow these five key middle-aged habits have been found to live for years without chronic diseases, including type 2 diabetes, cardiovascular disease and malignancies. This remarkable text, which contains information on whether there is a diet to strengthen immunity, whether we really need 10,000 steps a day and how to achieve the required amount of night rest, is available free of charge at the following link.