DIET, BODY, AND MENTAL HEALTH. Diet or food is to build up the body of humanity, physically, mentally, and spiritually, eating the right food at the right time, maintains a better body structure of humanity, to keep the body, soul, and spirit healthy, require the right food, at the right time, food provide humanity the energy to carry out the required daily activities, food is very important, essential, and necessary to humanity, for a life long sustainability. Digging deep about the importance of food to humanity, take us to have a critical study of how food help the human brain to function properly for optimum performance in handling critical issues, especially , in critical thinking, eating healthy goes along way in keeping the brain sharp and alert, for fast thinking and response, to drive home the points, eating healthy keep humanity mentally healthy. Especially, vegetables, fruits, fish, and fish oil. Reference: University of Oslo, Norway. Dept. Of health Psychology.