The study of nutrition may focus on how to prepare healthy foods, which diets can cause diseases or how to store different kinds of foods. The study of how foods affect people can be beneficial for nutritionists, health bloggers or personal trainers.

The PhD is a doctoral degree, specifically called a "doctor of philosophy" degree. This is misleading because PhD holders are not necessarily philosophers (unless they earned their degree in philosophy!). That said, PhD recipients are able to engage in thought experiments, reason about problems, and solve problems in sophisticated ways.