What does this quote mean in Chapter 24? “His food doesn't stick going down, does it”

Great question--when I teach this book, I get a lot of questions on this quote.

Mrs. Merriweather has just subtly (well, somewhat subtly) insulted Atticus. Miss Maudie responds with the above quote. There are two interpretations I give to my students.

1. Miss Maudie is referring to Mrs. Merriweather eating Atticus's food. Mrs. Merriweather is is Atticus's house, eating Atticus's food, in front of Atticus's sister and daughter and others that respect him. Miss Maudie's come back is asking Mrs. Merriweather (snidely) if Atticus's food is good enough to eat, even though Mrs. Merriweather insults Atticus.

2. The other explanation is that Miss Maudie is referring to Atticus eating food. Atticus knows he did the right thing, defending Tiom, and therefore, doesn't have a troubled conscience, so he can doing things freely, without feeling guilty--such as eating.