as all Catholics know is that no food or liquids other than water can be consumed for one hour before communion. However, this a greatly mitigated form of the communion fast that was in place until the 1950s. Prior to that, the fast was from all foods and drinks, water included, from midnight until the communion. Father William Saunders, in an article writing in the Arlington Catholic Herrald gives a good short history of the communion fast and the reason for it.
As he notes, the communion fast is regulated in canon law. The canon reads in full:
Can. 919 §1 Whoever is to receive the blessed Eucharist is to abstain for at least one hour before holy communion from all food and drink, with the sole exception of water and medicine.
§2 A priest who, on the same day, celebrates the blessed Eucharist twice or three times may consume something before the second or third celebration, even though there is not an hour's interval.
§3 The elderly and those who are suffering from some illness, as well as those who care for them, may receive the blessed Eucharist even if within the preceding hour they have consumed something.
For most Catholics, it is section 1 of the canon which regulates our behavior. Note that the fast is to be for at least one hour before communion. In other words, the Church has allowed each individual to make a determination about how long the fast should be given his condition.
A person with a full night's rest, no unusual physical needs, etc. should have no problem following the ancient discipline of fasting from midnight on. Those engaged in work overnight might be placing their work and even their lives in jeaopardy by doing so, as hunger could lead to faintness and accidents, and so a shorter fast would then be appropriate. But the received tradition of the church is to fast in order to purify ourselves, and to stir up a holy hunger for the bread of life and the cup of salvation.
Each person is allowed to judge for himself, but as with any other decision, we should be informed by the practice of the Church which is not only the living but also those who have gone before.