Samples of human bone from the Lowland Maya site of Lamanai, Belize have been analyzed for the trace elements strontium, magnesium, and zinc, and for delta¹⁵N and delta¹³C of collagen, in order to test various models of diet over the time range from pre-Classic (1250 BC to 250 AD) to Historic (1520 AD to 1670 AD) periods. The content of maize in the diet is inferred from delta¹³C which is, in turn, negatively correlated with both strontium and zinc content. Maize constitutes about 50% of the diet in the oldest pre-Classic samples, decreases in importance to a minimum of about 37% in Terminal Classic times and subsequently rises to about 70% of the total diet in post-Classic times. The delta¹⁵N of collagen remains essentially constant over this 2,000-year period (9.9±0.9 per mil (per thousand)), indicating essentially no change in the balance of protein sources, dominantly from wild and domesticated animals. ¹⁵N enrichment in a tomb burial suggests consumption of seafoods by very high-status males.