Such a warning against self-cannibalism even offers further proof of the authority, infallibility and inerrancy of God’s Holy Word. (Are you listening Richard Dawkins?)
There is no way around it. We are all guilty of gnawing on our arms.
Scientist/theologian Emanuel Swedenborg made this problem rationally clear when he pointed out that Holy Scripture was written in a symbolic language (correspondences) that contained deeper meanings and deeper truth.
To decipher this profound psycho-spiritual language one must start from the literal words of human terrestrial language and raise their meanings to a higher level or analog.
Here is how:
Since an “arm” represents where we have our power, and the “flesh” represents the living part of the arm, when the Bible mentions people eating the flesh of their arms it means that he or she is swallowing the conviction that one should only trust the power of their own life-abilities and prudence (rather than God’s).
So even if your physical arm shows no teeth marks, if you favor your own wisdom and judgment over God’s, you are spiritually chomping on your own flesh.
Without a grasp or knowledge of this higher interpretation of the words and narratives in the Holy Word, the human race will remain as a primitive society, in spite of any new technology that comes along!