Is it true that among the Sunnah regarding obedience to parents is not eating with them, or eating lightly with them, to honor them and avoid eating what they desire?

There is no indication in the Sunnah (definition) that refraining from eating with one's parents is an act of righteousness, unless they prefer it. It has been narrated concerning some of the Tabi'in, such as Ali ibn al-Husayn, that he would not eat with his mother, as an exaggeration in showing her dutifulness. This was out of fear that her eyes might fall upon some food and he would eat it without his knowledge, thereby disobeying her.