Ask the doctors: How long does it take to stick to a new habit?
Q: I had always heard that it takes three weeks to get a new habit to stick, but now people are saying it's more like three months. Is that right?
Last year, I made a resolution to stop eating sugar, and I'm still fighting (and losing) that battle. What makes new habits so hard?
A: You have asked two very interesting questions that will take us in two somewhat different directions. The first is about the length of time it takes to lock into a new habit. We have an updated answer from newer research.
The second opens a discussion of the differences between a habit and a behavior. That may seem like splitting hairs, but the definitions hold key clues to common roadblocks as well as strategies that can lead to success.
Let's start with the three-week timeline. It comes from an observation made in a 1960 self-help book. In this book, a plastic surgeon said that's how long it took for his patients to get used to their altered appearances. Not surprisingly, subsequent studies have found the time frame to be both longer and more fluid.
That includes conclusions from researchers in Australia, who analyzed data from 20 studies conducted between 2008 and 2023. In those studies, 2,601 people between the ages of 21 and 73 reported their progress in trying to acquire new habits. These goals included exercising, flossing, taking vitamins, drinking more water and eating healthier. The researchers found it took between two and five months to develop a new habit, and that the actual time frame ranged from four days to nearly a year.
That brings us to an important distinction. A habit, such as flossing, is a single, repeatable action. Behavior change, like the one you are struggling with in quitting sugar, is more complex.
When you look at it closely, a new behavior often requires a collection of new habits, which helps explain why it can be hard to adopt. Flossing, for example, is triggered by the clear cue of brushing your teeth. But reducing sugar means making a series of choices throughout the day. That creates many decision points where, depending on mood, stress level or social setting, it can be easy to relax or abandon the guidelines you have set.
With your goal to eat less sugar, it can be helpful to analyze your daily routine and pinpoint the potential stumbling blocks. These might include a morning coffee break, lunch with co-workers or late-night snacking. Choose the situation that feels easiest to change, and decide in advance on a different response.
If you've been having a cookie with lunch, consider a baked good made with less sugar. Gradually reducing the portion size of a sweet treat also works. Break complex behavior into smaller habits, and then tackle those one by one. This makes change more manageable.
Be sure to give yourself plenty of time and grace, if you falter, for a new behavior to become your new habit.
• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.
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