Most of our New Year’s resolutions have one thing in common: resisting temptation. Trying to ignore the powerful allure of the forbidden cigarette, doughnut, or latest budget-blowing buying impulse requires willpower. You might expect very successful people, who presumably have boatloads of willpower, to be particularly good at not giving in. But, if anything, they seem to be even more susceptible to temptation than the rest of us. Quick! Name a famous or powerful person that doesn’t have a well-known weakness for something. I’ll wait.

Having the willpower to govern a country, yet lacking the willpower to resist cigarettes or French fries may seem like a contradiction, but it actually isn’t according to research on the nature of self-control. So if you want this to be the year that you finally stop smoking, slim down, or stick to your budget, it’s a good idea to start by understanding how willpower really works.

Your capacity for self-control is not unlike the muscles in your body.

Like biceps or triceps, willpower can vary in its strength, not only from person to person, but also from moment to moment. Just as well-developed biceps sometimes get tired and jelly-like after a strenuous workout, so, too, does your willpower “muscle.”

Even everyday actions like decision-making or trying to make a good impression can sap this valuable resource, as can coping with the stresses of your career and family. When you tax it too much at once or for too long, the well of self-control strength runs dry. It is in these moments that the doughnut wins.

The first thing you are going to want to do, if you are serious about resisting temptation, is make peace with the fact that your willpower is limited. If you’ve spent all of your self-control handling stresses at work, you will not have much left at the end of the day for sticking to your resolutions. Think about when you are most likely to feel drained and vulnerable, and make a plan to keep yourself out of harm’s way. Be prepared with an alternate activity or a low-calorie snack, whichever applies.

Also, don’t try to pursue two goals at once that each requires a lot of self-control, if you can help it. This is really just asking for trouble. For example, studies show that people who try to quit smoking while dieting, in order to avoid the temporary weight gain that often accompanies smoking cessation, are more likely to fail at both enterprises than people who tackle them one at a time.

The good news is that willpower depletion is only temporary. Give your muscle time to bounce back, and you’ll be back in fighting form and ready to say “no” to any doughnuts that come your way. When rest is not an option, recent research shows that you can actually speed up your self-control recovery or give it a boost when reserves are low simply by thinking about people you know who have lot of self-control. (Thinking about my impossibly self-possessed mother does wonders for me when I’m about to fall off the no-cheesecake wagon.)

Or, you can try giving yourself a pick-me-up. I don’t mean a cocktail. I mean something that puts you in a good mood. (Again, not a cocktail. It may be mood enhancing, but alcohol is definitely not willpower enhancing.) Anything that lifts your spirits should also help restore your self-control strength when you’re looking for a quick fix.

The other way in which willpower is like a muscle (and the really great news for those of us trying to lose a few pounds) is that it can be made stronger over time, if you give it regular workouts.

Recent studies show that daily activities such as exercising or keeping track of your finances or what you are eating—or even just remembering to sit up straight every time you think of it—can strengthen your capacity for self-control. For example, in one study, people who were given free gym memberships and stuck to a daily exercise program for two months not only got physically healthier, but also smoked fewer cigarettes, drank less alcohol, and ate less junk food. They were better able to control their tempers and less likely to spend money impulsively. They didn’t leave their dishes in the sink, didn’t put things off until later, and missed fewer appointments. In fact, every aspect of their lives that required the use of willpower improved dramatically.

So if you want to build more willpower, start by picking an activity (or avoiding one) that fits with your life and your goals—anything that requires you to override an impulse or desire again and again—and add this activity to your daily routine. It will be hard in the beginning, but it will get easier over time if you hang in there, because your capacity for self-control will grow.

Armed with an understanding of how willpower works and how you can get your hands on some more of it, there’s no reason why this can’t be the year that you cross those troublesome resolutions off your list for good.

Dr. Heidi Grant Halvorson is a motivational psychologist and the Associate Director of the Motivation Science Center at Columbia University. She is the author of the best-selling books is Succeed: How We Can All Reach Our Goals and Nine Things Successful People Do Differently. For more on Dr. Grant Halvorson, please visit her website or follow her on Facebook or Twitter.

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