How do Roman Catholics interpret 1 Timothy 4:3 In it's context in the NRSVCE (including section title):

False Asceticism
4 Now the Spirit expressly says that in later times some will renounce the faith by paying attention to deceitful spirits and teachings of demons, 2 through the hypocrisy of liars whose consciences are seared with a hot iron. 3 They forbid marriage and demand abstinence from foods, which God created to be received with thanksgiving by those who believe and know the truth. 4 For everything created by God is good, and nothing is to be rejected, provided it is received with thanksgiving; 5 for it is sanctified by God’s word and by prayer. (1 Timothy 4:1-5 NRSVCE, emphasis added)

This passage appears to list forbidding marriage and demanding abstinence from foods as examples of 'teachings of demons'.
It seems that to enter the priesthood in the Latin rite either a promise (for diocesan priests) or a vow (for religious priests) of celibacy is required.  The best argument I've seen so far on this issue, argues that this isn't a 'requirement' but only something entered into voluntarily. But on the surface, this argument seems somewhat at odds with language used in some of the sections of the ordination ceremony of the Latin rite subdiaconate:

You ought anxiously to consider again and again what sort of a burden this is which you are taking upon you of your own accord. Up to this you are free. You may still, if you choose, turn to the aims and desires of the world (licet vobis pro artitrio ad caecularia vota transire). But if you receive this order (of the subdiaconate) it will no longer be lawful to turn back from your purpose. You will be required to continue in the service of God, and with His assistance to observe chastity and to be bound for ever in the ministrations of the Altar, to serve who is to reign. (Source, emphasis added)*

Even if the initial decision was voluntary, the process seems to admit no possibility for a later change.  A priest (in the Latin rite) is certainly forbidden from resiling from an earlier intention to remain celibate and to instead pursue marriage.
In regard to 'demanding abstinence from foods', I note that there has been a change since Vatican II, but we still have:

On Ash Wednesday and all of the Fridays of Lent, Catholics over the age of 14 are required to abstain from meat and from foods made with meat. (Source, emphasis added)

Now that doesn't sound particularly voluntary does it?
So what is the Catholic understanding of this verse and why isn't it referring to their practices in these areas?

edit: *I accept Matt Gutting's assurance that the order of the sub-diaconate has been dissolved and the particular text quoted is now only of historical interest and not necessarily a corresponding match to the instructions currently given to modern candidates for the Catholic priesthood. While I'm not sure that this has a significant effect on the underlying issue my question stems from (I'm not aware of a substantial change in the character of, or the requirements for the priesthood post-Vatican II), I'm certainly willing to update this reference to current intructions (or the recommended promissory/avowed responses) if someone is kind enough to provide the text for them.
I don't see this particular passage referred to in, for example, the Summa Theologica (where I might expect to see it in an Objection to a discussion of whether priests should be celibate). In fact, I don't see in the Summa (though surely it must be somewhere) any discussion of the question of priestly celibacy.

In the (standard Catholic) New American Bible, Revised Edition, the words are slightly different than in the translation you quote (highlighting the differences):


  Now the Spirit explicitly says that in the last times some will turn away from the faith by paying attention to deceitful spirits and demonic instructions through the hypocrisy of liars with branded consciences. They forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth. For everything created by God is good, and nothing is to be rejected when received with thanksgiving, for it is made holy by the invocation of God in prayer.


Note the perhaps significant omission of the comma after the word "foods".

This appears to point the meaning of the passage to things that will happen in "the end times", not now; and perhaps things that are wrong when enjoined generally, not in particular.

There is no note in the text about the third verse in particular, though a note on the passage as a whole reads:


  Doctrinal deviations from the true Christian message within the church have been prophesied, though the origin of the prophecy is not specified (1 Tm 4:1–2); cf. Acts 20:29–30. The letter warns against a false asceticism that prohibits marriage and regards certain foods as forbidden, though they are part of God’s good creation (1 Tm 4:3).


In addition, consider Paul's words in 1 Corinthians 7:8:


  Now to the unmarried and to widows, I say: it is a good thing for them to remain as they are, as I do


which appears to endorse celibacy for those not currently married (though the rest of the chapter accepts marriage as a godly state, under the principle of "everyone should accept the life to which he was called").

It seems, then, that to the extent that the Catholic Church has a particular interpretation of this verse, it interprets it to mean that celibacy and fasting are wrong when enjoined on everyone at all times, but not if enjoined on particular groups or at particular times.



With respect to the words of the ordination to the subdiaconate: Keep in mind that the Order of the Subdiaconate was dissolved over 40 years ago; it's not surprising that you're looking at words (probably dating back to the time of the Council of Trent) that take a very strict view of celibacy. There are two Orders in the Church now: deacons and priests. The Order of Deacons is no longer simply a "first step" to the priesthood; deacons are ordained as permanent deacons. They are under no immediate obligation of celibacy, and indeed I've known very few unmarried permanent deacons. They are, however, obliged not to marry after their ordination.

Priests are, of course, obliged to be celibate at as well as after their ordination; but even there the requirement can be dispensed from. I've known a couple of married Latin-rite priests. They were ordained Anglican priests who converted to Catholicism and petitioned Pope Paul VI to allow them to become priests. He dispensed them from the requirement of celibacy. I don't believe such a dispensation is in the cards again; but it is possible (the Code of Canon Law, canon 1042 note 1, lists marriage as an impediment to ordination, but canon 1047, section 2, note 3 allows the Pope to dispense from this requirement).

As far as abstinence from meat: This is a traditional Catholic observation; however, it's not strictly necessary. Canon 1253 states: 


  The conference of bishops can determine more precisely the observance of fast and abstinence as well as substitute other forms of penance, especially works of charity and exercises of piety, in whole or in part, for abstinence and fast.


So it's not an absolute requirement; in addition, if an individual has (for example) a medical condition which would be worsened by abstinence from meat, he or she is excused from that requirement. The USCCB's website states:


  A.  Those that are excused from fast and abstinence outside the age limits include the physically or mentally ill including individuals suffering from chronic illnesses such as diabetes.  Also excluded are pregnant or nursing women.  In all cases, common sense should prevail, and ill persons should not further jeopardize their health by fasting. 


(emphasis added)