Torah at the table turns eating into life

ואיתא ג' שאכלו על שולחן א' ול"א עליו ד"ת כאילו אכלו מזבחי מתים.

And it is taught: three who ate at one table and did not speak words of Torah upon it — it is as though they ate from "sacrifices of the dead" (zivchei meisim).

The Mishnah (Avos 3:3) warns that a meal without divrei Torah is like eating from offerings to the dead. The Sefas Emes will explain why eating without Torah is associated specifically with "death."

כמ"ש לעיל כי האכילה היא ענין השינוים והכל בחי' מיתה.

As was said above, that eating is a matter of changes (shinuyim), and all of this is the aspect of death.

Eating belongs to the world of constant change and decay — food is transformed, consumed, broken down. All such flux is rooted in mortality, the realm of "death" where nothing endures.

אבל האומרים עליו ד"ת נק' שלחן שלפני ה' שמתעלה אל השורש ע"י התורה שנק' עץ חיים.

But those who speak words of Torah upon it — it is called "the table that is before Hashem," for it is elevated to the Root through the Torah, which is called the "Tree of Life" (Eitz Chaim).

When divrei Torah are spoken at the meal, the very same table becomes "the table before Hashem" (the Shulchan of the Beis Hamikdash). The Torah, the Eitz Chaim, lifts the act of eating out of the realm of decay and binds it back to its eternal Root.

ונק' זה השלחן בלי השתנות כנ"ל:

And this table is called one "without change," as above.

Once Torah has elevated it, the table is no longer subject to the changes of "death" — it is joined to the unchanging life of the Eitz Chaim.

Summary: Eating belongs to the world of change and decay — the aspect of death — which is why a meal without Torah is likened to "sacrifices of the dead." But speaking divrei Torah, the Eitz Chaim, raises the very same table to its Root and transforms it into "the table before Hashem," a place of unchanging life.