Healthier habits: how to make changes that last

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The short answer

Habits form when you repeat a simple action in the same situation until it starts to happen without much thought. In one well-known study this took 66 days on average, with a range of 18 to 254 days. Missing a single day made little difference. Start small, tie the new habit to something you already do every day, plan for the moments that usually derail you, and be patient.

Most of us know what we “should” be doing for our health. We should eat more vegetables, sleep better, move more and manage stress. Knowing isn’t usually the problem. The hard part is doing it on an ordinary Tuesday when you’re tired, busy or out of your usual routine.

That’s why I spend as much time with patients on how to make changes as on what to change. A plan only works if it fits into your real life.

Why do new health habits fade?

Most new habits start with motivation: a new year, a worrying test result or a burst of energy. Motivation is useful for getting started, but it rises and falls. When it dips, we fall back on whatever we do automatically.

Psychologists describe a habit as an action that is triggered by a situation, such as a time of day, a place or something you’ve just done, rather than by a conscious decision. Once a habit is established, it takes very little willpower to keep going.

That’s the goal: to move a healthy choice from “something I have to remember and push myself to do” to “something I just do”.

How long does it take to form a habit?

You may have heard that it takes 21 days. The research suggests it usually takes longer, and that it varies a lot from person to person.

In a study at University College London, volunteers chose one healthy action to do every day in response to the same cue. Examples included eating a piece of fruit with lunch or going for a 15-minute run before dinner. On average it took 66 days before the action felt as automatic as it was going to get. For some people it took 18 days. For others it was estimated to take around 254 days.

Simpler actions, such as drinking a glass of water, became automatic sooner. Exercise habits took about one and a half times as long.

Two findings from that study are encouraging:

Missing a day doesn’t undo your progress. A single missed day had little effect on how automatic the habit became. What matters is getting back to it the next day.
Repetition in the same situation is what builds the habit. The more consistently you link the action to the same cue, the faster it becomes automatic.

Seven ways to make a healthy habit stick

1. Start smaller than feels necessary

Choose a version of the habit that is so easy you could do it on your worst day. Two minutes of stretching, one extra portion of vegetables at dinner, or putting your phone in another room at 10pm. Once it’s automatic, you can build on it.

2. Link it to something you already do

Attach the new habit to a cue that already happens every day: “After I pour my morning coffee, I’ll take my supplements” or “When I get home from work, I’ll change into my walking shoes”. Your existing routine becomes the reminder.

3. Make an “if–then” plan

Decide in advance exactly when, where and how you’ll act, and what you’ll do when something gets in the way. For example: “If it’s raining at lunchtime, then I’ll do 15 minutes of the exercise video instead of my walk.”

These plans are sometimes called implementation intentions. A review of 94 studies found that they had a medium-to-large effect on whether people reached their goals.

4. Change your surroundings

It’s easier to make a good choice when it’s the easy choice. Put fruit and nuts where you’ll see them, and keep biscuits out of sight. Leave your walking shoes by the door. Charge your phone outside the bedroom. Small changes to your environment do a lot of the work that willpower would otherwise have to do.

5. Focus on one change at a time

It’s tempting to overhaul everything at once. For most people that leads to burnout within a few weeks. Pick one habit, give it time to settle, then add the next. Over a year, a handful of well-established habits will do far more than a long list of changes you can’t keep up.

6. Track it simply

A tick on a calendar or a note in your phone helps you see your progress and spot patterns, such as the days when things tend to slip. Keep it simple. The aim is awareness, not perfection.

7. Be kind to yourself on the off days

Everyone has days when the plan falls apart. That’s normal, and the research shows that one missed day doesn’t set you back. The habit that matters most is getting back on track the next day without giving up. You can read more about this in Why it’s not your fault when a health plan feels hard to follow.

Which habits make the biggest difference?

In my clinic, the habits that tend to have the widest benefits are the foundations:

Area	A small habit to start with
Nutrition	Add one portion of vegetables or pulses to a meal you already eat
Sleep	Go to bed and get up at the same time each day, including weekends
Movement	A 10-minute walk after your main meal
Stress and recovery	Five minutes of slow breathing before you start work or before bed
Hydration	A glass of water with each meal

The right starting point depends on you. If poor sleep is affecting your energy, appetite and mood, sleep may be the habit that makes everything else easier. Read Can sleep quality really transform your health?

When it helps to have support

Some habits are harder to change because something else is getting in the way. That might be fatigue, hormonal changes, poor sleep, digestive symptoms or a very demanding life. In these cases, it’s worth looking at what’s underneath before expecting willpower to fix it.

At the clinic, our health coach Joanna is a Functional Medicine Certified Health Coach. She works alongside patients to turn their health plan into small, realistic steps, and to adjust them as life changes. Find out more about health coaching.

Common questions

How long does it take to form a new habit?

In one study it took 66 days on average for a new daily health habit to become as automatic as it would get. It ranged from 18 days to around 254 days, depending on the person and the habit. Simple habits, like drinking water, tend to form faster than exercise habits.

Does missing a day ruin a new habit?

No. Research found that missing a single day had little effect on how automatic a habit became. The important thing is to pick it up again the next day.

What is the best way to build a healthy habit?

Start with a very small version of the habit, link it to something you already do every day, and plan in advance what you’ll do when something gets in the way. Repeating it in the same situation is what makes it automatic.

Should I change several habits at once?

For most people it’s better to focus on one habit at a time. Once it feels automatic, add the next. This is more likely to lead to changes that last.

Ready for support with your health plan? Book a free discovery call to talk about where to start.