Corn has been king for a long time

University of Calgary archaeologists found corn starch residues in ancient pottery shards. “Their discovery shows the spread of maize out of Mexico more than 9,000 years ago occurred much faster than previously believed and provides evidence that corn was likely a vital food crop for villages in tropical Ecuador at least 5,000 years ago (U of C website, EurekAlert).” As described in the paper “Directly dated starch residues document early formative maize (Zea mays L.) in tropical Ecuador”, residues of maize with both soft and hard endosperm were found on cooking pots and grinding tools, indicating that both types were grown by the people there.

Importantly, although we do not deny that maize played a significant role in Andean ceremonial life, our results show that it was indeed consumed as food as part of a diverse subsistence system. Our results indicate that a greater percentage of hard endosperm versus soft endosperm maize was cooked in the pots analyzed from Loma Alta. The higher percentage of soft endosperm maize present on the grinding stones may indicate extensive milling of soft endosperm maize to produce flour, resulting in a higher recovery rate from those artifacts. Other starches identified in the ceramic residues show that maize was one of a complex of crops exploited [including manioc, arrowroot, chili peppers, and jackbeans].

In other words, the evidence shows that early Ecuadoreans started using the traditional ingredients of Central American cooking from a very early date. The authors of this paper remind us that “There are dietary reasons why maize, beans, and chili peppers would be cooked together. Whereas maize is deficient in the essential amino acids lysine and tryptophan, and in niacin, legumes contain these essential dietary components and the consumption of maize and beans together complement each other and are nutritionally complete; chili peppers are high in vitamin C, which increases the absorption of iron.” The evidence also shows that the Ecuadoreans had been farming crops such as squash and beans well before the arrival of maize.  To me, this shows that these people were willing to adopt new farming strategies, even if they had not seen them before.
The residues also show that the people were cooking in very sophisticated ways, such as “the addition of lime (calcium hydroxide) Ca(OH)2, lye (sodium hydroxide) NaOH, or wood ash (potassium hydroxide) KOH” to “increase the temperature at which starches gelatinize, as does the addition of salts and/or sugars to the water.” This is known as alkali or alkaline cooking, and is a good way to improve the amount of bioavaliable iron in maize tortillas. Lactic acid works too, as described by Amy Proulx in her interesting paper “Fermentation and Lactic Acid Addition Enhance Iron Bioavailability of Maize”.
It so amazing that these people knew what were the best ways to obtain nutrients from their available plant foods over 5000 years ago! We might all be better off if we took their advice.