Student or Learner
My aunt is never happy when she had to wait in line, and people who try to squeeze in front are a special sore point with her. One day a young man at the supermarket stepped up to her just as she reached the checkout counter. "Mind if I go ahead?" he asked. "I just have this one can of dog food." "Goodness, no," she said, " If you are that hungry, go right ahead!"
I would like to know why my aunt think a young man is that hungry.
This is funny, but it's not easy to explain why.
Your aunt thought the young man was being rude by pushing in so she made fun of him by sarcastically pretending to think he was going to eat the dog food.
What she said meant was 'If you are so hungry that you can't wait eat that dog food, go right ahead'.
Hope that makes sense.