in Guides & Advice

16 02 2022

Myth Busting, Does It Take 21 Days To Form a Habit? Let’s look at the evidence and see if there is any weight behind the claims.

Where does 21 days come from?

Habits are the be-all and end-all in health so it’s no surprise people are keen to understand how long they take to form. However, this magic number of 21 days doesn’t, for want of a better expression, “add up”. The number came from a plastic surgeon called Dr Maxwell Maltz in the 1950s.

Typically, when Dr. Maltz would perform an operation he found that it would take the patients a minimum of 21 days to get used to seeing their new face. Similarly, when a patient had an amputated body part like a leg or arm, he noticed that the patient would sense a phantom limb for about 21 days before adjusting to the new circumstance. 

He also noticed with his own behaviour that it took around 21 days to wire in a new habit and because this pattern kept emerging he reported it in his book ‘Psycho-Cybernetics’ that went on to sell over 30 million copies. 

This is where the problem started as that amount of hype influenced major life coaches and self-help professionals, from Tony Robbins to Zig Ziglar and everyone in between. 

So 21 days is enough to form a habit or not?

As with anything that gets recited often by more than one person, lots of things get lost in translation and what most forgot is that Dr Maltz said it takes a “minimum of 21 days” and therefore wasn’t making a definitive statement of fact. He was simply reciting his own personal experience and observation. N=1 is not a good statistic to base a conclusion on. The length of a habit timing idea was tested in a study by Phillippa Lally in the Health Psychology Department of University College, London. 

The study examined the habits of 96 people over a 12-week period. Each person chose one new habit for the 12 weeks and reported each day on whether they did the behaviour and how automatic the behaviour felt.

They showed that the time it took for participants automaticity (do it without thinking) ranged from 18 to 254 days, with the average being 66 days. As you can see there is a large range, and this spread depends on how easy or hard the new habit is. Invariably the easier a new habit is, the faster the learning curve.

The Truth: The truth is that it will probably take you around two to eight months to lock in a new habit depending on how hard or easy you make it on yourself — not 21 days. However, it shouldn’t be a numbers game because you’re going to have to keep doing it for it to become effective.

Article by: Declan Doyle PhD Scholar & Combat Fuel Nutritional Expert.

Declan is a leading nutrition and health consultant and Combat Fuel’s go to nutritional expert. He has worked within elite performance environments both in sport and business for over 15 years. His clients range from world class combat athletes to your average Joe (or Jill) to large corporates. Outside of the ‘day job’, he still coaches people online and tutor’s newbie learners to be standout personal trainers. He continues to develop his knowledge and skills and is currently undertaking a PhD in elite performance. When he’s not lecturing, training, coaching or writing specific courses, you’ll find him dropping knowledge bombs over on all his socials below.

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