Depending on which study or urban myth you believe, the typical American gains two to 10 pounds during the period between Thanksgiving and New Year’s. And there is no question that December is the spendiest month of the year. Credit card issuers can document it, and retailers count on it.

And January? That's when we resolve to lose weight and save money. Can we attack them together? Or does it make more sense to do one, then the other? While many people will make an effort (good intentions but no specific plan) and others will look for the quickest fixes (deprivation), some of us will find that the changes hoped for in January feel like a normal part of life by June. If you need motivation for making financial changes, check out just how much your debt is costing you over the course of a lifetime. And know, too, that people who exercise and pay attention to what they eat tend to be healthier and feel better.

Ellie Kay, co-author of “Lean Body, Fat Wallet,” said it might be easier to do both at the same time since the same four habits are required for each endeavor. So success in one area helps reinforce the habits you need for the other.

1. A Sense of Entitlement Can Be Your Friend

The first habit is to monitor your thoughts and redirect them. If you’ve been stopping for milkshakes on the way home from soccer because it’s been a long, tiring day and you are entitled to a treat, change that. You are entitled to a life free of financial worry, and you are entitled to inhabit a body that is as healthy as you can make it. You deserve those things. You are worthy of them. And so taking a walk is what you do because you are entitled to it; you are worth taking care of. Got that? No? That is why it bears repeating. Over and over until you believe it.

Athletes visualize success because it’s a tool that works. See yourself succeed (and watch those reruns). Because it will take some time to override those old thoughts of, “I always start well, but…” and “I just can’t get control of my sweet tooth.” Every year, some people succeed. Tell yourself that in 2015, you will be one of them.

2. Have a Plan for Temptations

The second habit is what the authors call the 3-D habit, and it's a way to keep bad habits from getting the better of you. The D's are for determine, distract and delay. Determine your goal (and remind yourself of it). In the face of temptation, find a way to distract yourself so that you can perhaps interest or immerse yourself in an activity that does not run counter to your goals. And finally, delay. Feel like you must have the carrot cake or the 75%-off Christmas decorations? Can you see if the need is just as urgent in an hour? Do you have a buddy you can call for support?

3. Keep Up With the Numbers

The third habit is knowing and keeping up with your numbers. It essentially means recognizing that the intake and outgo are, one way or another, going to balance out.

With weight, it means if you are taking in more calories (intake) than our body uses in a day (outgo), that unused energy will be banked in the form of fat. With money, it's making sure that every dollar that comes in has a destination and actually goes there (you want a fatter bank account). For both, the secret is tracking. You are essentially balancing a checkbook in real time.

It is only human to underestimate how long we exercised or how much we spent (overestimating the size of our bills or how many steps we took in a day is much less common). Knowing numbers also lets you measure progress. While you may be measuring steps walked or shrinking balances, your persistence may also be paying off in more global measures, like weight, blood pressure, cholesterol levels, net worth or credit scores. Monitoring your progress can help you keep track of how far you've come (you can see your credit scores for free on Credit.com, while you're at it).

4. Are You Counting the Minutes Until it’s Over?

The last habit is sustainability, meaning you could live this way and still enjoy your life. A couple of months back, Credit.com staffers went on a "spending freeze," with varying degrees of success. While a freeze can — and did — help shine a spotlight on areas where we could most easily cut back, it also showed us where it was extremely difficult to do so. And if you feel deprived, your efforts are doomed. Make sure you are not being so restrictive that you just can't wait for this to be over.

These four habits are the ones that, practiced consistently, can give you what you want. Here’s how it might look in practice. Kay says improving both physical and fiscal fitness requires some tracking, but the tracking isn’t difficult. In fact, you can do most of it on your smartphone while waiting in line, while on hold on the phone, etc. If you received a fitness tracker as a gift, use it. There are plenty of financial and fitness-tracking apps that can help you get control.

And although she concedes a healthier lifestyle may have some initial startup costs (let’s say you spend 10% more on groceries and avoid the pesticide-laden “dirty dozen” and replace some cheap, processed food with fresh fruits and vegetables), she says that over time, the cost of continuing to be unhealthy will outweigh any savings that come from eating cheaper, less nutritious food. So buy those athletic shoes with good support, but be sure you’re getting a good price. Also check with your health insurance, Kay says. Sometimes you can get a discount for enrolling in a fitness program or sharing fitness data that verifies you are getting a certain amount of exercise.

Get the Family on Board

She also recommends enlisting your family’s help — and making it fun. (Yes, fun.) There has to be room for fun. If you are able to eat a meal out, consider giving each child a spending allowance and allow them to keep what they do not spend. You won’t have to deny them $3 soft drinks; most will decide they would rather have money and drink water, and that lesson is important.

Decide on a family reward for paying off a certain amount of debt. (A camping trip can be fun, Kay notes, and plan modest splurges.) While it's good to tell kids that you're saving money or trying topay off debt, Kay cautions about telling children the amounts; that is not something they should worry about. You can share the small sacrifices you've decided to make to help save money, and ask what they can do. Talk to them about making money (that's the other way to help save more), and encourage budding entrepreneurs. Tell them the family is working toward financial peace and security. Tell them that you — and they — deserve it.

Recognize Enemies of Success

Among the threats to your success are rationalizing — and we all do it sometimes. Try hard to recognize it and get back on track. Also be careful about judging yourself too harshly. You won’t be perfect, and you won’t meet every single goal every single day. But if you are meeting weekly goals, you’re on your way to succeeding. (That means if if it’s 10 p.m. and you’ve walked only 5,000 steps and your goal was 10,000 that you need not lace up your shoes. Just walk more tomorrow.) Kay recommends being “diligent without being legalistic.”

Give your goals a reality check, too. Goals that are too ambitious set you up for failure — as do goals that are too vague. It’s reasonable to commit to doing aerobic exercise four times a week; it’s not reasonable to go to your 25th high school reunion looking just like you did when you graduated. It’s not reasonable to decide in January that by June you will have paid off $30,000 in debt if you have an average income. As motivating as it might be to dream that those things are going to happen, it is a recipe for failure.

Finally, don’t let procrastination keep you from being successful. It won’t be easier to start in February… or March. Trust us on this. Accept that you will screw up some days and fail to do what you hoped. And that you will succeed if you start again now instead of deciding that you blew it, and what’s the use of trying? A small setback doesn’t have to become a roadblock if you let that first habit — believing you are entitled to succeed — help you get back on track.

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This article originally appeared on Credit.com.