Is it possible for breakfast before a blood test to distort GGT result?

Which test? If you mean "glucose tolerance test", then breakfast beforehand will ruin it, as will not complying with the preparation. If you mean "gamma-glutamyl transpeptidase / transferase" or "drunk screen", breakfast matters less, but be advised that some normal non-drinking folks have a hereditary tendency to run a very high GGT and I have to write letters for a few such folks each year.
Yes. A GGT test needs three days on a diet with about 150 gm cabohydrates each day, and an overnight fast (at least 8 hours) before the test.