- Couples that exercise, lose weight or quit smoking at the same time have more success
- If one partner is healthy and the other does not, the success is not nearly as much, but it still has a positive impact
- Even if a couple that has been together a long time still has a big influence on each other
(CNN)If you are still working on those popular New Year's resolutions to lose weight or quit smoking there is a real secret to that successful behavior change.
Have your spouse or partner join you.
That will more than double your chance of succeeding at making a positive lifestyle change, according to a new study that is running in the latest edition of the journal JAMA Internal Medicine.
Researchers at the University College London found that couples who adopted a new and positive health behavior together were more successful than those who tried to change on their own.
That was true for both men and women. It also held up for people who were older than 60. That came as a little bit of a pleasant surprise to co-author Jane Wardle.
"We weren't sure that with people who have been together for a long time you would see the same effect. You might think that they have settled into a certain way of doing things," said Wardle, a professor of clinical psychology and epidemiology at University College London. "This (success) suggests that they are in fact still listening to each other." Even after all these years.
To reach this conclusion, researchers looked at data from nearly 4,000 married and cohabitating couples. They studied unhealthy behavior in three lifestyle areas -- smoking, physical activity and obesity.
For people who quit smoking, something earlier research has shown is one of the hardest health behaviors to change, some 48% of men were successful in their attempt to quit if their partner also threw their cigarettes away. That's compared to the 8% of those people whose partner did not stop smoking. That's an enormous difference.
Women saw a similar result if their male partners also quit smoking.
They had a 50% success rate versus the 8% of those who successfully quit smoking while their partners kept up the habit.
When it came to physical activity men had a 67% success rate at adopting a healthy exercise routine if their female partners did, versus a 26% success rate if the partner did not exercise more.
For weight loss men had a 26% success rate if their partner was also dieting versus a 10% success rate for those who had partners that were not working on losing weight.
For women 36% successfully lost weight if their partners joined them in their weight loss plan, versus the 15% of those with success, without a supportive partner.
The research showed that if both people in the relationship were unhealthy and tried to make a change, then they had success. If there was an unmatched couple -- say one who smoked and one who didn't, the results weren't as strong.
It is unclear what exactly it is about a relationship that increases successful behavior change. It could be the healthy competition or the support. And in the future, Wardle and her colleagues would like to see if an intimate partner has more of an influence on you than friends or a support group like Weight Watchers. But bottom line, Wardle believes having a partner who wants to help you change to be healthier and is someone who is willing to take the time to do it with you does matter.
"Having someone who is with you day and night encouraging you and supporting you, this truly is a powerful result," Wardle said.