This is a peer-reviewed chapter in an open access book, Personalized Medicine in Relation to Redox State, Diet and Lifestyle. Several diet-related conditions where personalized care can revolutionize treatment, control and prevention of lifestyle diseases are discussed (Type II diabetes, obesity, cardiovascular diseases, cancer, oral health and osteoporosis). This chapter serves as an introductory overview of the subject. The chapter is accurate, relevant and clear. It is a technical reading that is best suited to nurses, nutritionists and other allied health professionals at both the undergraduate and graduate level.