Dieting is irrational. It makes no sense to suppose that someone who has failed to eat no more than he should, will all of a sudden be successful at eating far less than he should. That’s like a man in debt thinking his first step should be to get rich. (No, first get out of debt.) Or someone who is out of shape thinking his first step should be to train for the Olympics. (No, first attain ordinary fitness.)

Moreover, a diet is unsustainable. Thus, someone who attempts to diet is starting something which, in principle, he cannot continue for his whole life -- and when he gives it up, as he must, what then?

No, it makes more sense simply to begin, today, to eat just as one should eat, always. The correct description of such a resolution is not “to go on a diet” but rather “to attempt to acquire the virtue of ‘moderation’” (or ‘temperance’, as that cardinal virtue is sometimes called). Moderation is the virtue by which we seek pleasures of food, drink, and sex no more than is appropriate for health, and insofar as they are not inconsistent with what is right.

To give an example of how this approach would work: Suppose you are a 40 year old male of average height, who weighs 200 pounds -- which is about 30 pounds more than your ideal weight. To maintain your present weight, which is excessive, you need to consume 2,300 calories a day (assuming a sedentary lifestyle). But to maintain yourself at your ideal weight, you would need to consume 2,100 calories per day. (You may discover all of this through online calculators of ideal weight and Resting Metabolic Rate.) Thus: start eating, today, no more than 2,100 calories.

Make this a permanent resolution for how you plan to live the rest of your life -- since that is how you should live anyway -- and eventually, as a sort of by-product, you’ll reach your desired weight and shape.

Once such a resolution is understood, correctly, as an attempt to acquire an aspect of the virtue of temperance, the effort gets put into the proper context. Perhaps someone’s overeating is of a piece with some lack of sexual control. Perhaps this person needs to acquire at least minimal habits of mortification. Maybe a love of comfort or some type of self-absorption needs to be addressed.

Of course, if you are thinking of improving your body in the New Year by dieting and exercise, you might think also of improving your soul.

Actually, as the mention of the virtue of “temperance” shows, there can be no true improvement of the body without also an improvement of the soul. (I would suggest that this link is one reason why, despite repeated experience, we continue to find the bad behavior of athletes off the field so scandalous, and why we reject, as if morally wrong, improving the body through drugs.)

But if we wish to turn our attention to the good of our soul itself, then, following the principle already set down, our question should be: “What care of the soul should I be showing anyway on a daily basis? How can I change my life to make it as I should be living, always?”

By “care of the soul” I mean what improves our relationship to God, and to others as made in the image of God.

Here’s what you might think you should be doing anyway on a daily basis, as Catholic: make a morning offering (the moment you wake up); say the Rosary, preferably with one’s family; spend some time (15 minutes at least) in mental prayer; read the Bible; examine your conscience (for a few minutes, before bed). You might even consider attending Mass and receiving Communion each day, as much as is practicable. If you do none of these things consistently, start with one.

Some general observations are in order.

First, don’t resolve anything without also asking God’s help in keeping one’s resolution. The human will is wounded and weak because of Original Sin. It follows that it is impossible for it to correct its own weakness: for the will which attempts to correct itself is likewise wounded and weak. No effect can be greater than its cause.

That’s why it recognized, for serious cases, as in 12-step programs, that the weak person must acknowledge his helplessness and call upon a “higher power” for assistance. But what holds so dramatically for major failings holds also for even the smallest resolution of self-improvement. So make resolutions and take all the usual steps for keeping them -- keep a record, tell a friend, set reminders -- but also pray for grace.

Second, expect to fail. Every attempt at self-control is also an occasion for self-knowledge, and not infrequently God lets us fail, so that we know our weakness better and turn more decisively to him. I know someone who resolved one Lent to get up each day at 6 a.m. He succeeded on Ash Wednesday, but failed every day after that all the way through Easter. It was a good Lent.

Third, respond to failure by “beginning again.” Just as a child learning to walk stumbles and falls, but then gets back up and starts walking again as if nothing had happened, so, after we fail at a resolution, we can “brush it off” and, with a childlike spirit, simply begin anew.

Michael Pakaluk is Professor of Psychology at the Institute of the Psychological Sciences in Arlington, Va. His ninth son, Blaise Francis Emmanuel, was born on Dec. 14.