The explanation, from "Clothing the political man: A reading of the use of khadi/white in indian public life" by Dipesh Chakrabarti, Postcolonial Studies, Vol. 4, No. 1, 2001:
Behold the mighty Englishman
He rules the Indian Small,
Because being a meat-eater,
He is five cubits tall.
Gandhi quotes [this] 'doggerel of the Gujarati poet Narmada' that was popular 'amongst the schoolboys'. The doggerel captures the colonial nationalist understanding of the role of the body in the construction of political power.