Forget 21 days. Most healthy new habits take at least two months to stick

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Wondering why you’re already struggling with that New Year’s resolution? A new study suggests that forming healthy new habits takes a lot longer than we thought.

For years, popular wisdom has held that it takes just 21 days to add a new habit to your daily routine. But according to recent research from the University of South Australia (UniSA), new habits typically take around two months to engrain, and can take up to almost a year.

The researchers reached this conclusion after conducting a meta-analysis of 20 earlier studies, published between 2008 and 2023, and involving more than 2,600 participants. These studies measured habitual behavior to find an overall trend in the length of time taken for healthy habits to form. Habits included exercise, drinking water, taking vitamins and flossing.

The researchers hope their findings will motivate people to stick with trying to form healthy habits even if it is taking longer than expected.

“I think the main thing is that it helps people set realistic expectations,” Ben Singh, research fellow at UniSA Allied Health & Human Performance and co-author of the study, told CNN. “It’s not often a quick fix.”

The study, published in the journal Healthcare, found that the median time taken to form new, healthy habits was 59-66 days, but it could take as long as 335 days.

Singh stressed that how long it takes to form healthy habits is different for each person and depends on what the habit is.

“Sometimes we found that the simple behaviors, (like) if someone wanted to start flossing each day, might take someone a week to get into their routine,” Singh explained, “but more complex behaviors such as changing someone’s diet and physical activity can take a lot longer.”

He explained that the 21-days myth stems from the 1960 book “Psycho-Cybernetics” by plastic surgeon Maxwell Maltz, in which the author observed that his patients typically took around 21 days to get used to their new appearance following surgery.

Singh said people held onto the idea of a “quick fix” as motivation. So, is there a danger that the new research will make them more reluctant to try to establish new habits in the first place?

“There is the possibility that it will put people off and maybe discourage them and demotivate them,” said Singh. “(But) some people (who) may think that it’s going to take them 21 days, but then after 21 days they’re still struggling, then at least this research and this evidence provides people with some realistic benchmarks that they can follow.”

Singh said the study also offers specific tips for forming healthy habits.

“If (people) want to start eating healthier or exercising more, then integrating those new habits in the mornings tends to be more effective than trying to integrate them later on in the day,” he said, “because people tend to lose motivation or get busier later in the days, (so) they’re less likely to follow that behavior.”

For example, if you want to get into a habit of eating more fruit, Singh recommends having an apple with a morning coffee.

Benjamin Gardner, director of the Habit Application and Theory (HabitAT) Group at the University of Surrey, England, suggested the results of the study should be interpreted carefully.

“It is important to urge caution around the idea that people either ‘have a habit’ or ‘don’t have a habit’, which is implicit in this study,” Gardner, who was not involved in the research, told CNN. “In reality, habit varies on a continuum – in other words, habit becomes stronger over time, rather than reaching a magic point at which it is ‘fully formed.’”

Gardner said the best way to form a habit is through what is known as “context-consistent repetition,” identifying a situation that you encounter regularly, and then doing your chosen behavior each time you encounter that situation.

More research is still needed to find out how successful people were in sustaining the new habits examined in the study, Singh noted.

“A lot of the research was quite short term,” he said. “We really need a lot more longer-term research. So (if) someone has successfully changed their habits and improved their behavior after 12 weeks, are they still following that behavior 12 months down the track?”

The overall message of the research is clear, though: If you want to make 2025 your year of healthy habits, be patient – the new you may well make an appearance in a matter of months rather than weeks.

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