If you absolutely cannot function without coffee, or find yourself putting bacon on everything you eat, those cravings could be genetic. Researchers at the University of Trieste, and the Burlo Garofolo Institute for Maternal and Child Health performed genome-wide association studies (GWAS) to locate the genes that cause us to prefer certain foods over others. The study found 17 genes that connect to liking certain food such as coffee, bacon, ice cream and dark chocolate.
These studies are all a part of nutrigenetics, which explore the effects between nutritional food and genetic information to find how it relates to ones health.
You can read more in an article by Carl Engelking in Discover Magazine at http://goo.gl/70puKb.