An Evolving Definition of a “Healthy Diet”

Throughout life, most of us eat at least three meals a day for 365 days a year. It follows that, in a 90-year life, everyone is potentially exposed to food constituents (i.e., nutrients, bioactives, and other chemical compounds) more than 95 thousand times; therefore, dietary habits are a relevant determinant of health status. In daily clinical practice, we usually discourage patients from eating foods deemed unhealthy, such as highly processed items. Even more rarely do we recommend that patients consume healthy foods, except as an alternative to junk foods. Nevertheless, it is well known that a healthy diet prevents several chronic and degenerative diseases and is the key to a healthy and long life. However, what is a healthy diet and how do we define it? Recently, a large number of epidemiological studies have attempted to identify which dietary factors correlate with negative health outcomes, including death, loss of function, and lack of well-being. Determinants of positive health outcomes have been more rarely investigated, on the contrary.