The nitrogen isotope ratios are typically elevated compared to those of later farming populations, indicating a higher proportion of animal protein in the diet.

For Cheddar Man specifically, stable isotope analysis is consistent with the diet that would be expected from a Mesolithic hunter-gatherer in the Mendip Hills: primarily terrestrial game, with possible contributions from freshwater fish and plant foods that are less isotopically visible.

The specific composition of his diet across different seasons is harder to reconstruct from isotope analysis, which gives an average picture rather than a seasonal one.

Sequential sampling of different regions of a tooth — teeth grow incrementally, like tree rings, with each increment reflecting the diet during the period when that part of the tooth was forming — can in principle provide a seasonal dietary record.