Not to eat (το μη φαγειν). "The not eating." Articular infinitive (second aorist active of εσθιω) and subject of καλον εστιν (copula, understood).

Flesh (κρεας). Old word, in N.T. only here and 1. Corinthians 8:13.

To drink (πειν). Shortened form for πιειν (second aorist active infinitive of πινω).

Whereby (εν ω). "On which thy brother stumbleth" (προσκοπτε).