The science behind making and breaking New Year’s resolutions

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It’s hard to escape discussions of New Year’s resolutions this time of year, whether you make them or not.

New Year is a popular time for goal setting and resolutions, in large part due to “The Fresh Start Effect,” which is a behavioral science theory that people are most likely to make big goals and life changes at calendar milestones like birthdays or a new year. But is New Year’s a good time of year to set a goal? According to experts, it’s complicated.

We asked experts about the science behind New Year’s resolutions — why we make them, why they fail and how to make them stick.

Getting started

Experts say setting a goal at the beginning of the year can be beneficial simply because you’re not doing it alone. This collective momentum can create accountability, inspiring people to stay the course. But making changes at the start of the year isn’t easy. Shorter days, colder weather and post-holiday fatigue can make it harder to maintain.

“Once we get into the middle of January, the holidays are over,” said Jess McCurley, a clinical health psychologist and assistant professor at San Diego State University. “The party has trailed off, all the excitement has died down, maybe the new toys, the new trinkets we got, the excitement is wearing off, and January is a dark time. Our days are short, the temperatures are often a bit cooler, and all that has an impact on our mental health.”

Luckily, you don’t have to wait until the beginning of the year or until next year to make a change or take advantage of “The Fresh Start Effect.” The beginning of the month, quarter or week can signal a fresh start.

For the highest chance of success, a goal-setting framework also matters. Simply setting the intention without a plan will not be helpful. SMART goals — an acronym that stands for specific, measurable, achievable, realistic and time-bound — are a useful way to make resolutions attainable, whether you set them at the New Year or next week.

Breaking bad habits and facing addiction

Quitting an addiction is incredibly hard, especially if relying on willpower alone. According to the United Nations Office on Drugs and Crimes 2025 Annual Report, more than 316 million people worldwide use drugs, showing just how common — and complex — dependency can be.

Many behaviors fall into a “habit loop:” a cue, a routine and a reward. Once established, this loop feels automatic, which makes it challenging to stop.

While willpower helps with breaking minor habits, experts warn that chemical dependencies, such as alcohol or opioids, affect the brain and body differently. For these, medical supervision is often necessary.

For nonmedical habits, while it can be tempting to go cold turkey, intentional, incremental reductions are often more sustainable. Eve Lasswell, a clinical psychologist and associate clinical professor at the University of California San Diego recommends leaning on the wisdom of taking “one day at a time.”

Kicking a bad habit takes time. Lasswell said that after denying the brain and body a substance or habit, it can take many months to get back to a baseline.

Having self-compassion is vital because slip-ups are common and expected. For example, less than 1 in 10 adults who smoke cigarettes succeed in quitting each year, according to the Centers for Disease Control and Prevention.

Getting fit

Health-related resolutions make up 79% of all New Year’s resolutions, according to a 2024 Pew Research Foundation study. January sees such a predictable spike in new gym memberships that there is even a term for it — the “January Gym Phenomenon” — but gyms also see a steep drop in attendance in February and March as new routines begin to waver. Experts recommend the best way to tackle new health goals is to build them into your daily routine.

Chad Prokop, associate executive director of the South Bay YMCA said the “January Gym Phenomenon” is a result of setting unrealistic expectations.

“They’ll start out quick, but after they don’t see any immediate results, they say ‘this isn’t worth it,’ and they drop off,” he said. To succeed in fitness goals, experts recommend making specific goals for the best results.

McCurley recommends building momentum first. “Let’s say your goal is to be fit or run a marathon, but right now you don’t even run a mile; you need to start small, so start by building up your walking. Or if you want to run, run 1 mile or run 10 minutes, something very small, and do that a few times a week. And make that be your goal for several weeks — start there.”

Healthy eating

Chances are, you know someone on a diet this time of year. While fad diets and fasting may be trendy, following good nutrition and eating a healthy quantity can have lasting effects without as big a shock to the body.

While many of us think we know what healthy eating is — less processed sugar, highly processed and fried foods — nutrition and a balanced diet are more involved than that.

A Nutrition IQ survey found that 89% of Americans claim they know nutrition basics, but 91% of them say they don’t know how much protein, fiber, carbs, sugar and salt they consume daily.

Clinical nutritionist Tara Coleman advised that many aren’t getting enough protein: “The biggest thing that you can do is make sure that every single time you eat, there is a source of protein.”

Experts recommend a diet rich in nutrient-dense foods like vegetables, fruits, beans, eggs and fatty fish, and reducing highly processed foods.

“The majority of your food should not be in packages. So ideally, you’re looking for whole foods, things like that. But don’t worry, I also live in the real world. And so if I’m looking at a package, I’m looking at the ingredients. I want to see — number one — are these words I’ve ever heard of, and hopefully I have, in which case I throw it in the basket.” Coleman said.

Shopping for healthier food and limiting the unhealthy snacks in your environment can help prevent falling into bad habits. “the food that we reach is the food we eat, so the food that is right around us, that’s sitting on our counter or in the break room in your office or in your pantry, is what you’re going to end up eating, especially if you have a moment where you’re feeling tired or stressed or in a hurry.” McCurley said.

Experts say Sleep is a surprisingly overlooked factor in healthy eating. Poor sleep disrupts hunger-regulating hormones, which can cause food cravings and decreased willpower.

“You might be somebody with the most willpower in the world, but if you’re getting really bad sleep over and over, and your hunger hormones are getting out of whack, it’s going to be really hard to resist those highly palatable foods, highly salty foods, sweet foods that we want to eat,” McCurley said.

Financial check-up

Whether making money goals excites you or scares you, the New Year is a good time to review fiscal goals for the year.

It can be tempting to set ambitious money goals, but according to experts, starting small is a better approach.

“I’m definitely a proponent of saying that you should start off small, only because I think too many people get derailed by letting perfect be the enemy of good,” said Paul Lim, a certified financial planner at The Wealth Consulting Group.

Data from a 2025 TIAA Institute study shows that only 49% of Americans surveyed understand basic financial principles. Luckily, there are more free financial resources available than ever before, from apps to podcasts to online tools.

But, if starting from zero, a good place to start would be to build up emergency savings. The Federal Reserve reported last year that more than one-third of Americans do not have enough savings to cover a $400 emergency expense.

The next step is tracking income and expenses to spot necessary adjustments. Online tools can help automate bill payments, savings and investing, while saving time and eliminating human error.

“Automating your savings transforms the act of saving into a compulsory good behavior, into something that not only happens automatically, but it becomes like it’s part of your bill,” Lim said.

A common mistake, Lim said, is not having a clear understanding of debt and interest rates. Take time to read through financial statements and pay off higher interest rates first.

Taking charge

January is National Mental Wellness Month, and setting goals and getting active can be a huge boost for your mental health, but remember to give yourself grace. Experts say goal setting should be empowering, not a source of stress, so don’t be too hard on yourself if you stumble.

Across psychology, fitness, nutrition and finance, experts agree: lasting change doesn’t come from willpower alone.

The takeaway is simple: start small, be specific and build momentum. Whether your goal is better health, stronger finances or breaking a habit, progress happens one step at a time.