I had to look for the missing details and here is my answer:
The excerpt is from "The Time Traveler's Guide to Elizabethan England".
This excerpt details the different ideas from Thomas Elyot and Richard Carew and their views of what health and diet is. Based on this, the central idea that the Elizabethans trusted in relation to body humors and health is that, this paragraph shows how diet could disturb humors' balance.
