In fact, the author didn't explain it, but it was introduced in his speech: gluttony represents endless desires. After satisfying the appetite of the guests, Sanniang retaliated against those hateful nobles one by one, took back their greedy desires, and kneaded them into delicious food. This shows the author's original intention of writing this book: it not only tells us what "desire" is, but also tells us a lot about the truth of being a man and the charm of food.