What does the author want readers to do? Learn more about avoiding high blood pressure and kidney disease.
Eat mostly processed foods and avoid shopping in the outer ring of the supermarket.
Become informed about healthy eating options and make better choices.
Follow a strict eating plan created by a nutritionist.

the author develops a cold, and scared tone. making the reader shudder with fear, and suddenly become cold. i'm guessing that he's writing a scary novel, or maybe about a chilly december night.

cockroaches and rats often are a symbol for things that are disgusting or vile. though i don't know which play you are talking about, i hope this !