From your own experience, are you more likely to finish half a pizza by yourself on a) Friday night after a long work week or b) Sunday evening after a restful weekend? The answer that most people will give, of course, is “a.” And in case you hadn’t noticed, it’s on stressful days that many of us give in to temptation and choose unhealthy options. The connection between exhaustion and the consumption of junk food is not just a figment of your imagination.

And it is the reason why so many diets bite it in the midst of stressful situations, and why many resolutions derail in times of crisis.

How do we avoid breaking under stress? There are six simple rules.

1) Acknowledge the tension, don’t ignore it.

Usually in these situations, there’s an internal dialogue (albeit one of varying length) that goes something like this:

“I’m starving! I should go home and make a salad and finish off that leftover grilled chicken.”

“But it’s been such a long day. I don’t feel like cooking.” [Walks by popular spot for Chinese takeout] “Plus, beef lo mein sounds amazing right now.”

“Yes, yes it does, but you really need to finish those vegetables before they go bad, plus, they’ll be good with some dijon vinaigrette!”

“Not as good as those delicious noodles with all that tender beef.”

“Hello, remember the no carbs resolution? And the eat vegetables every day one, too? You’ve been doing so well!”

“Exactly, I’ve been so good! I can have this one treat…”

And so the battle is lost. This is the push-pull relationship between reason (eat well!) and impulse (eat that right now!). And here’s the reason we make bad decisions: we use our self-control every time we force ourselves to make the good, reasonable decision, and that self-control, like other human capacities, is limited.

2) Call it what it is: ego-depletion.

Eventually, when we’ve said “no” to enough yummy food, drinks, potential purchases, and forced ourselves to do enough unwanted chores, we find ourselves in a state that Roy Baumeister calls ego-depletion, where we don’t have any more energy to make good decisions. So–back to our earlier question–when you contemplate your Friday versus Sunday night selves, which one is more depleted? Obviously, the former.

You may call this condition by other names (stressed, exhausted, worn out, etc.) but depletion is the psychological sum of these feelings, of all the decisions you made that led to that moment. The decision to get up early instead of sleeping in, the decision to skip pastries every day on the way to work, the decision to stay at the office late to finish a project instead of leaving it for the next day (even though the boss was gone!), the decision not to skip the gym on the way home, and so on, and so forth. Because when you think about it, you’re not actually too tired to choose something healthy for dinner (after all, you can just as easily order soup and sautéed greens instead of beef lo mein and an order of fried gyoza), you’re simply out of will power to make that decision.

3) Understand ego-depletion.

Enter Baba Shiv (a professor at Stanford University) and Sasha Fedorikhin (a professor at Indiana University) who examined the idea that people yield to temptation more readily when the part of the brain responsible for deliberative thinking has its figurative hands full.

In this seminal experiment, a group of participants gathered in a room and were told that they would be given a number to remember, and which they were to repeat to another experimenter in a room down the hall. Easy enough, right? Well, the ease of the task actually depended on which of the two experimental groups you were in. You see, people in group 1 were given a two-digit number to remember. Let’s say, for the sake of illustration, that the number is 62. People in group two, however, were given a seven-digit number to remember, 3074581. Got that memorized? Okay!

Now here’s the twist: half way to the second room, a young lady was waiting by a table upon which sat a bowl of colorful fresh fruit and slices of fudgy chocolate cake. She asked each participant to choose which snack they would like after completing their task in the next room, and gave them a small ticket corresponding to their choice. As Baba and Sasha suspected, people laboring under the strain of remembering 3074581 chose chocolate cake far more often than those who had only 62 to recall. As it turned out, those managing greater cognitive strain were less able to overturn their instinctive desires.

(Photo: PetitPlat)

This simple experiment doesn’t really show how ego-depletion works, but it does demonstrate that even a simple cognitive load can alter decisions that could potentially have an effect on our lives and health. So consider how much greater the impact of days and days of difficult decisions and greater cognitive loads would be.

4) Include and consider the moral implications.

Depletion doesn’t only affect our ability to make good decisions, it also makes it harder for us to make honest ones. In one experiment that tested the relationship between depletion and honesty, my colleagues and I split participants into two groups, and had them complete something called a Stroop task, which is a simple task requiring only that the participant name aloud the color of the ink a word (which is itself a color) is written in. The task, however, has two forms: in the first, the color of the ink matches the word, called the “congruent” condition, in the second, the color of the ink differs from the word, called the “incongruent” condition. Go ahead and try both tasks yourself…

The congruent condition: color matches word.

The incongruent condition: color conflicts with word.

As you no doubt observed, naming the color in the incongruent version is far more difficult than in the congruent. Each time you repressed the word that popped instantly into your mind (the word itself) and forced yourself to name the color of the ink instead, you became slightly more depleted as a result of that repression.

As for the participants in our experiment, this was only the beginning. After they finished whichever task they were assigned to, we first offered them the opportunity to cheat. Participants were asked to take a short quiz on the history of Florida State University (where the experiment took place), for which they would be paid for the number of correct answers. They were asked to circle their answers on a sheet of paper, then transfer those answers to a bubble sheet. However, when participants sat down with the experimenter, they discovered she had run into a problem. “I’m sorry,” the experimenter would say with exasperation, “I’m almost out of bubble sheets! I only have one unmarked one left, and one that has the answers already marked.” She explained to participants that she did her best to erase the marks but that they’re still slightly visible. Annoyed with herself, she admits that she had hoped to give one more test today after that one, then asks a question: “Since you are the first of the last two participants of the day, you can choose which form you would like to use: the clean one or the premarked one.”

So what do you think participants did? Did they reason with themselves that they’d help the experimenter out and take the premarked sheet, and be fastidious about recording their accidents accurately? Or did they realize that this would tempt them to cheat, and leave the premarked sheet alone? Well, the answer largely depended on which Stroop task they had done: those who had struggled through the incongruent version chose the premarked sheet far more often than the unmarked. What this means is that depletion can cause us to put ourselves into compromising positions in the first place.

And what about the people, in either condition, who chose the premarked sheet? Once again, those who were depleted by the first task, once in a position to cheat, did so far more often than those who breezed through the congruent version of the task.

What this means is that when we become depleted, we’re not only more apt to make bad and/or dishonest choices, we’re also more likely to allow ourselves to be tempted to make them in the first place. Talk about double jeopardy.

5) Evade ego-depletion.

There’s a saying that nothing good happens after midnight, and arguably, depletion is behind this bit of folk wisdom. Unless you work the third shift, if you’re up after midnight it’s probably been a pretty long day for you, and at that point, you’re more likely to make sub-optimal decisions, as we’ve learned.

So how can we escape depletion?

A friend of mine named Dan Silverman once suggested an interesting approach during our time together at the Institute for Advanced Study at Princeton, which is a delightful place for researchers to take a year off to think, plan, and eat very well. Every day, after a rich lunch, we were plied with nigh-irresistible desserts: cheesecake, chocolate tortes, profiteroles, beignets—you name it. It was difficult for all of us, but especially for poor Dan, who was forever at the mercy of his sweet tooth.

It was daily dilemma for my friend. Dan, who was an economist with high cholesterol, wanted dessert. But he also understood that eating dessert every day was not a good decision. He contemplated this problem (along with his other academic interests), and concluded that when faced with temptation, a wise person should occasionally succumb. After all, by doing so, said person can keep him- or herself from becoming overly depleted, which will provide strength for whatever unexpected temptations lie in wait. Dan decided that giving in to daily dessert would be his best defense against being caught unawares by temptation and weakness down the road.

In all seriousness though, we’ve all heard time and time again that if you restrict your diet too much, you’ll likely to go overboard and binge at some point. Well, it’s true. A crucial aspect of managing depletion and making good decisions is having ways to release stress and reset, and to plan for certain indulgences. In fact, I think one reason the Slow-Carb Diet seems to be so effective is because it advises dieters to take a day off (also called a “cheat” day–see item 4 above), which allows them to avoid becoming so deprived that they give up entirely. The key here is planning the indulgence rather than waiting until you have absolutely nothing left in the tank. It’s in the latter moments of desperation that you throw yourself on the couch with the whole pint of ice cream, not even making a pretense of portion control, and go to town while watching your favorite tv show.

Regardless of the indulgence, whether it’s a new pair of shoes, some “me time” where you turn off your phone, an ice cream sundae, or a night out—plan it ahead. While I don’t recommend daily dessert, this kind of release might help you face down challenges to your will power later.

6) Know Thyself.

(Image: AnEpicDay)

The reality of modern life is that we can’t always avoid depletion. But that doesn’t mean we’re helpless against it. Many people probably remember the G.I. Joe cartoon catch phrase: “Knowing is half the battle.” While this served in the context of PSAs of various stripes, it can help us here as well. Simply knowing you can become depleted, and moreover, knowing the kinds of decisions you might make as a result, makes you far better equipped to handle difficult situations when and as they arise.

This blog originally appeared on Tim Ferriss’ blog, here.