In book 3 of the Iliad, Helen, from the top of a Trojan tower, points out to Priam some of the Greek heros.
First Priam asks “who is this Achaean man, so noble and tall. Yet there are others taller than him by a head”
ὅς τις ὅδ᾽ ἐστὶν Ἀχαιὸς ἀνὴρ ἠΰς τε μέγας τε.
ἤτοι μὲν κεφαλῇ καὶ μείζονες ἄλλοι ἔασι,
The answer is Agamemnon. So we have established although tall he is shorter by a head than some other warriors.
Next Priam asks “Come tell me, dear child, who,is this man shorter by a head than Agamemnon the son of Atreus although his shoulders and back look broader”
‘εἴπ᾽ ἄγε μοι καὶ τόνδε φίλον τέκος ὅς τις ὅδ᾽ ἐστί:
μείων μὲν κεφαλῇ Ἀγαμέμνονος Ἀτρεΐδαο,
εὐρύτερος δ᾽ ὤμοισιν ἰδὲ στέρνοισιν ἰδέσθαι.
The answer is Odysseus. So he must be two heads shorter than the taller warriors. Maybe the diet on Ithaca was a low protein one.
The is another interpretation. “By a head” (κεφαλῇ) is translated by some as “in stature” so that Odysseus would still be shorter but not by two heads!