THE MAKROBOI (or Macrobi), the "Long Lived Ones," was the name given to a number of long-lived Indian tribes, including the Kyrnoi and Gymnetai.

Pliny the Elder, Natural History 7. 27 (trans. Rackham) (Roman encyclopedia C1st A.D.) :
"The Indian race of Cyrni according to Isigonus [a Greek writer] live to 140; and he holds that the same is true of the long-lived Aethiopes, the Seres (Chinese) and the inhabitants of Mount Athos--in the last case because their diet of snakes’ flesh, which causes their head and clothes to be free from creatures harmful to the body.
Onesicritus [Greek historian C4th B.C.] says that in the parts of India where there are no shadows there are men five cubits and two spans height [about 8 feet], and people live a hundred and thirty years, and do not grow old but die middle-aged.
Crates of Pergamenus [Greek writer C2nd B.C.] tells of Indians who exceed a hundred years, whom he calls Gymnetae, though many call them Macrobi (Long-Livers)."

Sources:

• Pliny the Elder, Natural History - Latin Encyclopedia C1st A.D.