Lecture, three hours. Requisites: course 100, Public Health 200A, 200B. Designed to teach students how to apply principles of trial design and data analysis to lifestyle interventions for purposes of preventing onset and progression of diseases. Focus on noncommunicable chronic diseases (i.e., obesity, diabetes, hypertension, coronary heart disease, or cancer), but concepts and methods can be applied to acute and infectious diseases as well. S/U or letter grading.