Answer to Question 1
During sleep our BMR decreases, thus reducing our caloric requirement. Mr. Y still had a significant amount of food to be digested and absorbed which would result in increased levels of blood glucose, amino acids, and triglycerides. Instead of Mr. Y staying awake and doing some activity to burn off some of the excessive calories he took in, he is allowing his BMR to decrease. The excessive calories will be converted to adipose tissue.
Answer to Question 2
Because he ate so fast that he did not have a chance to digest and absorb a sufficient quantity of food to cause a significant elevation in his blood glucose.