Mutombo Coffee Research: Why You Drink Black Coffee? It’s in Your Genes

People who like to drink their coffee black also prefer dark chocolate, a new Northwestern Medicine study found. The reason is in their genes.

Northwestern scientists have found coffee drinkers who have a genetic variant that reflects a faster metabolism of caffeine prefer bitter, black coffee. And the same genetic variant is found in people who prefer the more bitter dark chocolate over the more mellow milk chocolate.

The reason is not because they love the taste, but rather because they associate the bitter flavor with the boost in mental alertness they expect from caffeine.“That is interesting because these gene variants are related to faster metabolism of caffeine and are not related to taste,” said lead study author Marilyn Cornelis, associate professor of preventive medicine in nutrition. “These individuals metabolize caffeine faster, so the stimulating effects wear off faster as well. So, they need to drink more.”