There are two different things going in those passages in Luke
Those two narratives aren't necessarily pointing toward what happens in Heaven, as there are varying interpretations to what is meant by the arrival of the Kingdom of God. Since you asked for a Catholic viewpoint, and this topic comes up a lot during the RCIA ministry, here's an explanation that tries to put those two different chapters in Luke into context.
- TL;DR: per St Thomas Aquinas, those who reach Heaven won't need to eat
The Fourth Cup
The best answer I've heard on why Jesus didn't drink the fourth cup at the Last Supper was presented by Scott Hahn in The Fourth Cup. (The link is to a transcript of his 40 minute long talk on the Eucharist; I'd recommend the audio disc/tape if you can get your hands on it).
In summary: Jesus established the New Covenant and important signs thereof and linked it directly to the Old Covenant celebration (Passover). Part of the significance of Him not drinking the 4th cup is that we (the faithful) now drink the 4th cup each time we receive communion and drink the precious blood. That is a departure from the Jewish tradition that led up to that final supper. Before the faithful receive the precious blood, who drinks from the cup? The celebrant of the Mass. The celebrant, be he priest or bishop acts "in persona Christi1" according to the Catholic teaching. This gets into the Catholic doctrine and practice of the Mass re-presenting (making it present again) key events in the Gospel, but one of the points that Hahn makes is that in this Sacrament the church also honors and fulfills the old covenant during the Mass.
Now what's the problem? The problem is that gospel account says
something like this: after the third cup is drunk Jesus says, "I shall
not drink again of the fruit of the vine until I am entering into the
kingdom of God." And it says, "Then they sang the psalms."
Every Jew who knows the liturgy would expect: and then they went ahead and said the grace and the blessing and had the fourth cup which climaxed and consummated the Passover.
But no, the gospel accounts say they sang the psalms and went out into
the night. {snip} Why did he skip the fourth cup? After all, he was raised a Jew, he'd been celebrating the Passover every year of his life since he was a little boy according to the strictest laws of Moses.
Rather than seeing this as Jesus prefiguring a meal in Heaven, he is prefiguring how the Body of Christ (The Church) will complete the Passover meal. The extended explanation, by Hahn, ties together a lot of scripture in the Old and New Testaments.
Raised from the dead in His glorified body, not a spirit walking around
In Luke 24, you have two different experiences of the disciples after the Crucifixion. The first is the two walking to Emmaus who spoke with him and didn't realize it was Him until he broke the bread, and then vanished.
The second was a larger group of the disciples who saw Him in his glorified body. As you noted in that passage, He ate food. He was raised from the dead, and was not simply a spirit people were seeing. (Recall also "doubting Thomas" sticking his finger into Jesus wounded side and seeing the holes in his hands).
The importance of what he was doing has been covered by St Thomas Aquinas in the Summa Theologica (Part III, Q 54) regarding Jesus in his Glorified Body.
Of the seven properties of the glorified body identified by St. Thomas Aquinas, the first three are relevant for the purposes of this answer:
(Summarized for brevity from here)
Identity: The glorified body will possess its original identity in
that it will be united to your soul. Your body will really be your
body, but that does not mean it will look the same as it did during
your life on this earth. When Jesus appeared to His disciples after
His Resurrection, He often had to make Himself known in some way,
even to those who were His closest disciples.
Integrity: The glorified body will be integral (complete), regardless
of how it was during its earthly life, or at the moment of its death,
or after it has decomposed in the grave. ...All glorified bodies will
be entirely integral.
Quality: This is the property of the glorified body by which everyone
in his glorified body will be as if in the prime of life.
Whether or not those in Heaven who leave their bodies behind eat and drink seems to be a different matter than what happens in our glorified bodies. If we are in our glorified bodies, then we can eat and drink. If we are purely in spirit in Heaven, before "the last day," we don't need to.
Saint Thomas Aquinas concludes that we will not eat in Heaven.
(Summa Theologica, Question 81)
Consequently those natural operations which are directed to cause or
preserve the primary perfection of human nature will not be in the
resurrection: such are the actions of the animal life in man, the
action of the elements on one another, and the movement of the
heavens; wherefore all these will cease at the resurrection. And since
to eat, drink, sleep, beget, pertain to the animal life, being
directed to the primary perfection of nature, it follows that they
will not be in the resurrection.
1 In the person of Christ the Head
. . . CCC 1548 In the ecclesial service of the ordained minister, it is Christ himself who is present
to his Church as Head of his Body, Shepherd of his flock, high priest
of the redemptive sacrifice, Teacher of Truth. This is what the Church
means by saying that the priest, by virtue of the sacrament of Holy
Orders, acts in persona Christi Capitis:23