Searching the net for "how to avoid garlic breath" some references come up.
Enter Ohio State University to help. Researchers there have evidence suggesting that we can neutralize bad breath naturally before it offends those around us. According to science, here are three ways to do it.
Recommended: raw apples, lemon juice, green tea.
Green tea is very high in antioxidants called polyphenols. As with the enzymes in the apple, polyphenols cover up the odor-causing chemicals in garlic.
Sheryl Barringer, one of the study's lead researchers, said that it’s best to use the bad breath cures at the same time you’re eating garlic. So we’d recommend adding some apples to that salad with garlicky dressing or using some lemon juice in your next garlic dip. Unless you want to squeeze the citrus straight into your mouth, that is.
And in a link found there, the chemical explanation is:
According to the researchers, foods deodorize garlic breath through two mechanisms. First, enzymes in the raw foods help to destroy the odors, and then, phenolic compounds in both the raw and cooked foods destroy the volatiles. This is why raw foods were generally more effective because they contain both the enzymes and the phenolic compounds.
It must be that raw garlic taken just before eating garlicky stuff works the same way. No magic. Maybe the researchers will see this and do a proper experiment :).