“Where do we see that studying Torah can be an adequate substitute for eating a meal? The verse mentioned earlier from this week’s parsha (‘…Not by bread alone does man live; rather, on all that comes from the mouth of God does man live’) may explain this.
The mitzvah of a Shabbat meal is not through eating ‘bread alone.’ We greatly enhance the meal by learning Torah – the Divine wisdom ‘that comes from the mouth of God’.”