Gospel of Mark indicates that john was eating "Akrides kai melion agurion." Locust and wild honey. https://biblehub.com/interlinear/mark/1.htm Mark 1 verse 6. ἀκρίδες https://biblehub.com/greek/akrides_200.htm ἀκρίδες means Locust, not carob.
I've been told that before, by a well-trained Bible scholar. You are right, of course. Was it OK for Israelites to eat bugs for protein? For John Baptist?
Jewish dietary ordinances under the Mosaic/Davidic Covenant:
"Yet these may ye eat of every flying creeping thing that goeth upon all four, which have legs above their feet, to leap withal upon the earth;
Even these of them ye may eat; the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind" (Lev. 11:21-22 AV).