It’s a strange way to start a holy season. Our foreheads are marked with ash, and we are reminded that we are dust and will soon return to dust.

In these post-Christian times, these words may seem off-putting, like something we would expect to hear at a secular “Celebration of Life” or in a pantheistic temple. Actually, they come from Genesis, addressed to our first parents immediately after their sin. The context helps a little, but it’s still potentially confusing.

Don’t we, as Christians, understand ourselves to be children of a Living God? Are we not destined for life everlasting? Why dwell on dust?

The dusty part of us is, of course, the physical body. God assembled it from the elements of this Earth, and it can collapse back into Earth in a remarkably short period of time.

Returning to dust isn’t the whole story of humankind, as we will be reminded some weeks hence. But the message of Ash Wednesday is still true: The physical body is part of what we are as human beings, and it’s corruptible and, indeed, already corrupted. That’s why the sacraments involve form and matter.

It’s why Jesus Christ was born as an infant and literally died on a cross.

It’s why the Church urges us, every year at Lent, to remember that we are dust and to remind ourselves what that means by doing bodily penance.

Fasting has always been the paradigmatic Lenten penance. In its most elemental form, that means giving up some food. That’s not to say that we shouldn’t do the other things: the media fasts, the Lenten devotions, the extra-special efforts not to carp at our co-workers or kids.

I always assign myself some (hated) spring cleaning and paper-sorting during Lent. Why not? It has to be done anyway, so I might as well do it in a properly penitential mood.

None of those things should replace the corporal penances, however. Don’t fool yourself into thinking that you, a sophisticated citizen of a modern liberal democracy, are somehow above those plebeian food fasts, able to focus instead on higher things.

Fasting is not some quaint vestige of a medieval, hair-shirt-and-torture-oriented time. It’s a mainstay of spiritual life for corporal creatures, the ones made of dust. That’s us.

If you don’t see the point of feeling hungry, or going without your daily smoothie or sweet roll, consider that this why-bother feeling is actually the basis of a pervasive modern predicament.

Living in a time of plenty, some of us find that we never have a good reason to say “No” to ourselves. This one cookie won’t turn me into a diabetic. This one glass of wine won’t make me into an alcoholic.

Fad diets are multiplying like rabbits nowadays, and one reason is just that we know we need to moderate in some way, but it’s hard to find principles on which to do it. Our appetites tell us to indulge, and the reasons not to indulge are often more abstract or obscure. Always saying “Yes” to our appetites is bad for our physical health, though. It turns out, it’s bad for our spiritual health, too.

Humans are creatures of appetites, but our appetites are not reliable indicators of our real good. We want things we shouldn’t have. And it gets worse: When we regularly indulge unhealthy appetites, they tend to grow.

Because we have so many opportunities today for feeding unhealthy appetites, our society is riddled with pathologies of overindulgence. Obesity is rampant, a massive pornography industry infects young and old alike, and recovery programs abound for a hundred different varieties of addiction.

Why are we so prone to self-sabotage?

Sociobiologists offer evolutionary theories to explain our destructive appetites; psychologists invent clinical terms for the various problems. Properly understood, these are all efforts to get useful perspective on a problem we all share: the hazards of being made of dust.

Obviously, unchecked appetites can enslave us and prevent us from fulfilling our earthly obligations. Even if we remain functional addicts, though, we’ll find that our oversized appetites are constantly on the brain, leaving us anxious and dissatisfied, unable to find the Christ-given peace we crave.

Lenten penance can help with this. It gives us a good and holy reason to deny ourselves, reining in some of our worst excesses and giving ourselves just a little bit more freedom for God. Lent can help us to find that holy peace, drawing our minds away from earthly pleasures and back toward our Creator.

Most of us probably enter Lent hoping to find those spiritual consolations. Hopefully we do, but sometimes we don’t. We find ourselves hungry, but not comforted. God seems distant, but appetite remains our constant companion.

At those times, we should recall a second reason for Lenten penance: It reminds us of our frailty.

Even if we are disciplined in our diets and diligent in our penances, most of us will probably find that our mind-over-matter efforts frequently fall short. We give up one little indulgence, only to realize a few months later that we’ve effectively replaced it with another. We realize to our horror that even healthy or virtuous-seeming things (such as physical exercise or devotional reading) can turn into an obsession, potentially becoming spiritual stumbling blocks.

In some sense, nearly all of us are “functional addicts” of one sort or another. We rely constantly on little comforts and consolations just to get ourselves through the day. We know that it would be better if we could let these earthly goods go, entrusting ourselves completely to God. That just seems too difficult.

It’s demoralizing to realize how quickly we can reach our limits. When Lenten penance pushes us to that point, we should reflect back on the words of Ash Wednesday.

“Remember that you are dust. To dust you shall return.”

There is more to this story, but before we can get there, we should spend some time really trying to live with our hungry, dusty selves.

Rachel Lu, a moral philosopher, wife, and mother of five, writes from St. Paul, Minnesota.