This is not a particularly original insight, but as I have recently read arguments answering the above question in the affirmative, I thought I would write about it today.
On one hand, it is undeniable that the shortened and moderated Eucharistic fast changes have made it easier for a Catholic in the state of grace to more frequently receive Holy Communion. And it is likewise true that in the last 100+ years, Popes have encouraged frequent Communion. Included in this group is Pope St. Pius X-- so this isn't some crazy novelty involved here.
Conversely, no Catholic in a state of mortal sin should receive Holy Communion (to round out the set, though not germane to this topic, it goes without saying that non-Catholics may not receive).
So, why the big fuss about the length of the Eucharistic fast? Don't we want frequent reception of Communion? And doesn't it seem better that a person who ate 2 hours ago receive Communion if he is properly disposed than to deny him Our Lord in the Eucharist for that reason?
Well, I would argue for a return to the longer Eucharistic fast for reasons of both piety and propriety. I think it would encourage the proper disposition for reception and require a more thoughtful and prayerful reception. And it would remove an encouragement to sacrilegious Communions.
Because many Catholics do not have a living memory of the former fasting requirements, I will briefly recount them here. The practice and expectation of fasting before Holy Communion goes back to ancient times. By the time of the 1917 Code of Canon Law the requirement was that a healthy Catholic who wished to receive Holy Communion must have fasted from everything, including water, from midnight of that day.
After some piecemeal indults and alterations over time and in specific places, Pope Pius XII changed this fast to a three hour fast from solid foods and a one-hour fast from liquids, reckoned (for the lay recipient) backwards from the time of Holy Communion. Also, alcoholic drinks were prohibited for the whole three-hour period, while neither water nor medicine broke the fast, even within the last hour.
Finally, Pope Paul VI shortened the fast to one hour, measured backwards from time of Communion, without regard to any distinction between solids or liquids, or between faithful and clergy. This practice is codified in the current Code of Canon Law. The practical consequence of a one-hour "fast" is that there is no meaningful fasting requirement at all. In any Sunday Mass, a Catholic could literally be munching a Snickers Bar walking into Church and be even money to be able to receive Communion. If he refrained from eating in the car on the way to Church, the fast is fairly guaranteed. Granted, for a daily Mass, one has to exercise a small amount of discipline.
OK, so, who cares? Well, if the word "fast" is to mean anything, surely a person who is fasting should feel like he has been deprived of food. That he is hungry. Or at least, that he notices that he hasn't been able to satisfy that bodily appetite.
Furthermore, back in the day (as they say), if anyone in the congregation noticed that a person did not go to Holy Communion, there was a ready explanation-- he or she must not have made the required fast. There was no scandal in the lack of reception. Today, with the ease of the "fast", the ignorance of the fast by many, and the absolute expectation (amounting to a practical mandate) for always receiving Communion at Mass, if a person does not receive Holy Communion the most ready explanation that would come to mind is that the non-recipient is in a state of mortal sin.
People are, as you might expect, human. Of course we are warned against rash judgment. It is a sin to assume that someone who does not go up to the Communion rail is guilty of mortal sin. We should be charitable, and if that fails we should just mind our own business. Conversely, no one in a state of mortal sin should receive Communion just to conceal the fact that he has committed mortal sin. Succumbing to peer pressure (real or perceived) and committing a second mortal sin to cover a first is not a good idea.
But people are influenced in these ways, and reviving a more stringent Eucharistic fast would go a long way to reducing unworthy, and even sacrilegious, reception of Holy Communion.
Recall, too, that often a person may be in doubt about whether he or she has committed mortal sin. He may be sitting in the pew trying to work it out. The lack of any immediate reason not to receive in the eyes of his fellow church-goers other than mortal sin might just be the final arrow needed in the quiver of rationalization. But a stringent Eucharistic fast that provides a ready, non-sinful reason to refrain from reception could be that final arrow in the quiver to avoid sacrilege and an uneasy conscience.
Back when the midnight fast was in force, Masses were expected to begin in the morning, and in no case could begin later than one hour after noon. With the frequency of Masses in late afternoons and evenings now, perhaps that fast could be modified while maintaining rigor. This is just my own proposal; I am not basing this on liturgical or historical arguments. In other words, feel free to suggest something else. But what if the new, restored Eucharistic fast went like this: Fasting from all solids and liquids (other than water) from midnight for Masses that begin at or before noon, and a three-hour fast (other than water) for Masses later in the day.
But any shoring up of a concept of fasting, even an uniform, three-hour fast, would be a welcome development.
By restoring the ancient practice and expectation for fasting prior to reception of Holy Communion, the Church would benefit souls. It would encourage the more reverent reception by those who receive, and also go far in removing the stigma for those who don't. No longer would souls in need of the confessional feel pressured to conceal their grave sins by committing other grave sins.
Everybody wins, right? So what are we waiting for?