“…Human carbon isotope data from the published studies listed in Table S2 were plotted to explore the relationship between δ 13 C values, time, and altitude (Figure 6) [24][25][26]35,56,58,63,[66][67][68]72,76,[79][80][81]84,88,93,94,97,105,107,108,111,116,[136][137][138][139]. The analyzed individuals in Phase 1 (third millennium BC) were from piedmont areas and oases situated in basins at altitudes ranging from 500 to 1500 m. It appears that their diets already included a combination of C 3 and C 4 plants.…”