Sustainable healthy habits: how to start and stick with them

What a habit is, and what it isn't

In psychology, a habit isn't just anything you do often. It's an action that starts almost by itself when a cue appears: a time of day, a place, something you've just done. It forms by repeating the same action in the same context.¹ That's why brushing your teeth after breakfast takes less effort than “exercising when I get the chance.”

That difference matters. A goal (“I want to get in better shape”) depends on you remembering and feeling like it every single time. A habit shifts part of that work onto the context. It doesn't replace motivation, but it takes some of the load off on the days motivation is missing.

Where to start: a few changes, chosen by you

The first decision isn't how, but what. An article for family doctors, written by three habit-formation researchers, recommends two things: that you choose the action yourself, and that you tie it to a time and a place you come across every day. According to the same article, making progress toward a goal of your own helps keep up interest.¹ We go over what information is needed to adapt a habit to your situation, and what research has found about personalized programs, in personalizing health habits.

One change or several at once? Here it pays to be honest. A review that compared programs tackling several health behaviors simultaneously or one after another found only six trials, and concluded that the evidence is limited and that both approaches should be considered equally effective.³ Starting with a single thing isn't “proven”: it's a practical option, and easier to evaluate, because if something changes you'll have a clearer clue as to what might be behind it. Why it's hard to tell which one worked when you change several things at once is what we explain in changing several things at once.

Spain's Ministerio de Sanidad (Ministry of Health) frames it as practical advice in its materials for the public: start with whatever is easiest and set small goals before taking on new challenges.⁷

Three questions can help you choose:

• Is it relevant to you now, or to someone else's life?
• Does it fit into your week as it is, without reorganizing all of it?
• In a few weeks, will you be able to tell whether you're doing it or not?

If what you want to sort out is rest, in Sleep better without complicating your routine we go over which practices have the most support and which have less than they seem to, so you can pick one.

Make it small and specific

Simple actions seem to become automatic sooner than elaborate routines. In the key study, people who chose a drinking behavior took a median of about two months to reach their automaticity plateau, and those who chose an exercise behavior, about three. With so few people the difference wasn't statistically significant, but the authors consider it consistent with the idea that a more complex action takes longer.⁸¹

Public health guidelines point the same way. The UK's National Institute for Health and Care Excellence (NICE) notes that small, manageable changes to daily routine are the most likely to be maintained.⁵ And the World Health Organization, in its physical activity recommendations, states that doing some activity is better than doing none and that bouts of any length count.⁹ Which minimums hold up when time is tight is the subject of healthy habits when you're short on time.

“Small” doesn't mean “unambitious.” It refers to the size of what you repeat, not of what you want to achieve. “Eating better” can't be repeated; “adding a piece of fruit to breakfast” can. The difference between a process goal and an outcome goal, and what research says about each, is covered in process and outcome goals.

Decide when and where: the “if–then” plan

There's a well-known gap between what you want to do and what you actually do. One of the most studied techniques for narrowing it is deciding the time and place in advance: “if I've finished lunch, then I go for a fifteen-minute walk.” In a meta-analysis of 94 independent tests, these plans had a medium-to-large effect on reaching goals.² To write your own, a template as simple as this will do: “When (something you already do every day, or at a fixed time), in (the place), I will (the action).”¹

The cue can be a fixed time or something you already do every day: your morning coffee, closing your laptop, putting the kids to bed. In a trial that compared the two options, there were no differences between them.¹¹ Linking a new action to one you already have is popularly called “habit stacking”; it isn't studied under that name in the sources consulted, but it rests on the same principle. How to choose a good anchor moment, and what the studies have measured, is what we explain in habit stacking.

Set up your environment

Part of the work can be done just once, by arranging things differently. A Cochrane review found that when a food was placed farther away, people ate less of it.¹³

For food, the same review compares “closer” with “farther away,” so moving what you want to eat closer has the same support, low as it is, as moving what you don't want farther away.¹³ For everything else—sneakers by the door, clothes laid out the night before—it's a sensible inference, not a proven finding. It costs little to try it and see whether anything changes.

Keep a simple record

Writing down what you do is one of the most studied techniques. In an analysis of 122 evaluations of healthy eating and physical activity programs, those that combined self-monitoring with at least one other self-regulation technique were more effective than the rest.¹⁴

Another meta-analysis, of 138 studies, found that monitoring your own progress helps you reach goals, more so when it's written down or shared with someone.¹⁵

For a habit, one mark a day is enough: done or not done. If you use a watch or a ring, it's worth knowing which data you can trust; we explain that in Wearables: useful data vs. noise.

What to expect: weeks or months, not days

There's no fixed number of days. In the few studies that have measured it, half of the people who managed to establish a habit—fewer than half of the participants in the two main studies—did so in about two months or less, with some cases taking a few weeks and others, projected by the model, many months.⁸¹¹ We go into detail in how long it takes to form a habit.

Skipping a single day didn't disrupt the process in the original study. Missing a whole week is another matter: its authors, drawing on other research, believe that does make it harder.⁸ And if after a few months the action still doesn't come automatically, that's not unusual: in those studies, fewer than half of the participants managed to establish the habit.⁸¹¹ Our suggestion: check whether the cue really shows up every day and whether the action is small enough.

After a bad week

A trip, an illness or a crunch at work will break any routine. It isn't an anomaly: a review of a hundred theories on maintaining behavior change starts from the premise that achieving a temporary change is common and maintaining it much less so.⁴ NICE explicitly asks behavior change programs to plan for relapses and to acknowledge that they're common.⁵

The same review groups into five factors what the theories propose keeps a change going (these are hypotheses, not measured effects): having a reason that still matters, knowing how to monitor and correct your own behavior, having physical and mental resources, the action having become a habit, and an environment and people that support you.⁴

What follows are practical suggestions consistent with those factors, not results from a trial:

• Come back with the smallest version of the action, not the one you were doing before you stopped.
• Check the cue: if your schedule has changed, maybe the “when” no longer works.
• Ask yourself what went wrong—time, fatigue, environment—before concluding that you lack willpower.

Where a habits guide reaches its limits

Almost all the evidence cited comes from studies in which someone asked participants to carry out a specific action and followed them for weeks—sometimes after a single initial session—not from reading a text on your own. The effects are averages, generally small or medium in size (medium to large for “if–then” plans), and nothing guarantees they will hold for any particular person.

Habits don't replace a health assessment either. If you have intense or persistent symptoms or a diagnosed illness, take medication, or are pregnant, talk to a health professional before making major changes to your physical activity or your diet.