From the earliest days of the Church, Christians have identified certain sins as more serious than others. For example, if a baptized Christian committed the sin of murder or adultery in the early Church, they would have to perform penance for years before being readmitted to the Eucharist.
Eventually, there came to be the “Seven Deadly Sins”, which include:
1) Lust
2) Gluttony
3) Greed
4) Sloth
5) Wrath
6) Envy
7) Pride
Each culture emphasizes, both in its practice and denunciation, different sins. For example, in our own American culture, Pride has been elevated to a good, while Lust and Greed are celebrated yet paradoxically also vigorous condemned. Envy and Wrath are seen as evils, although little understood, and Sloth appears to have little chance of gaining a serious foothold in our over-worked society.
That leaves Gluttony. There is no question that this sin is popularly indulged, as we are the most obese nation in the history of the world, yet how often have you heard any condemnation of gluttony from the pulpit or popular culture?

Sandow Birk - Gluttony
Because we are so obese, we are obsessed with weight loss, but this is not due to a rejection of gluttony but instead is based in pride and envy (and vanity): we don’t want to appear unattractive, so we indulge in every weight loss program that can be created in order to look good. Yet we want a diet that does not fundamentally change our inordinate desire for food; in fact, a diet often reflects a person’s obsession with food.
Like any sin, gluttony’s most serious danger is that it places something in the created order (in this case, food and drink) above the Creator. There is nothing wrong with enjoying food, but when the enjoyment of food becomes the priority (over the subsistence that food gives us) and when we persistently overindulge in food beyond our needs, then we have begun to fall into the sin of gluttony.
St. Augustine in his Confessions writes a moving passage about the struggle against gluttony (Book 10, par. 46-47, emphasis added):
You have taught me, good Father, that “to the pure all things are pure” (Titus 1:15); but “it is evil for that man who gives offense in eating” (Rom. 14:20); and that “every creature of thine is good, and nothing is to be refused if it is received with thanksgiving” (1 Tim. 4:4); and that “meat does not commend us to God” (1 Cor. 8:8); and that “no man should judge us in meat or in drink.” (Cf. Col. 2:16). “Let not him who eats despise him who eats not, and let him that does not eat judge not him who does eat.” (Rom. 14:3). These things I have learned, thanks and praise be to you, O my God and Master, who knocks at my ears and enlightens my heart. Deliver me from all temptation!
It is not the uncleanness of meat that I fear, but the uncleanness of an incontinent appetite. I know that permission was granted Noah to eat every kind of flesh that was good for food; that Elijah was fed with flesh; that John, blessed with a wonderful abstinence, was not polluted by the living creatures (that is, the locusts) on which he fed. And I also know that Esau was deceived by his hungering after lentils and that David blamed himself for desiring water, and that our King was tempted not by flesh but by bread. And, thus, the people in the wilderness truly deserved their reproof, not because they desired meat, but because in their desire for food they murmured against the Lord.
Set down, then, in the midst of these temptations, I strive daily against my appetite for food and drink. For it is not the kind of appetite I am able to deal with by cutting it off once for all, and thereafter not touching it, as I was able to do with fornication. The bridle of the throat, therefore, must be held in the mean between slackness and tightness. And who, O Lord, is he who is not in some degree carried away beyond the bounds of necessity? Whoever he is, he is great; let him magnify your name. But I am not such a one, “for I am a sinful man.” (Luke 5:8). Yet I too magnify your name, for he who has “overcome the world” (John 16:33) intercedes with you for my sins, numbering me among the weak members of his body; for your eyes did see what was imperfect in him, and in your book all shall be written down.
Gluttony has never been considered by a Church a minor sin but instead it has been seen as a “deadly” sin: it can kill us spiritually. Just like sex, a disordered desire for food can become an obsession that consumes our lives. Do we recognize the dangers of food in our spiritual lives today?