Professionals in dietetics and nutrition do more than push fruits and vegetables. Their understanding of the relationship between diet, health and disease allows them to teach and counsel people on healthy food selection, food preparation and good eating habits. Nutrition is a science that investigates the metabolic and physiological responses of the body to food and diet, and the role of nutrients in the cause, treatment and prevention of disease. A career in nutrition will allow you to serve as a credible expert who applies science-based principles to food and nutrition.