Английский Этимологический словарь - diet (1)

- "regular food," 12c., from O.Fr. diete, from M.L. dieta "parliamentary assembly," also "a day's work, diet, daily food allowance," from L. diaeta "prescribed way of life," from Gk. diaita, originally "way of life, regimen, dwelling," from diaitasthai "lead one's life," and from diaitan, originally "separate, select" (food and drink), freq. of *diainysthai "take apart," from dia- "apart" + ainysthai "take," from PIE base *ai- "to give, allot." The verb meaning "to regulate oneself as to food" (especially against fatness) is from 1660. An obsolete word for this is banting.