Chapter 6 of the Gita is all about meditation. Funny then, that verses 16 and 17 would talk about moderation in food. Is there really any sort of connection?
A very deep one in fact.
A spiritual aspirant may think that “we are all Brahman, we are not the body”. And such a person might decide to eat too much or too little, and in general become careless about his/her health.
As we very well know though, if we are sick, then there is little ability to get any work done – whether material or spiritual (including meditation progress or prowess).
That’s why Krishna makes it very clear in this verse, that extremes won’t do. The body is the tool and vehicle provided to us to achieve our spiritual objectives. The mind might like extremes, especially good ones, but the body thrives on moderation.