In a book titled The True History of Chocolate, authors Sophie Coe and Michael Coe used linguistic history to make the argument that the Olmec were the first people to consume cacao. Recently studies have been performed in an effort to confirm this argument using physical evidence.
As such, an analysis of 156 pottery sherds and vessels was completed in conjunction with the San Lorenzo Tenochtitlan Archaeological Project. The reason such vessels were tested was because cacao was said to have been consumed by the Olmec in liquid form, and would have the best chance of offering evidence of cacao residue, as they were served in such apparatuses (depicted below).
Cacao is composed of more than 500 different chemical compounds, archaeologists have identified theobromine as the substance to look for that indicates the presence of cacao. Thus, the study consisted of testing these Mesoamerican artifacts to see if there theobromine residue is present.
The results of the study proved to be fascinating, as theobromine was identified in several of the vessels tested in the analysis. This therefore supports the argument that Sophie and Michael Coe put forth in their book – meaning that the Olmec were consuming cacao starting around sometime between 1800 to 1000 BCE.
Powis, Terry G., et al. “Cacao use and the San Lorenzo Olmec.” Proceedings of the National Academy of Sciences 108.21 (2011): 8595-8600.