Are you looking forward to starting or changing something in 2021? Whatever your New Year's resolutions, there's an evidence-based way to make them stick for longer - and it's all in the phrasing.

Rather than telling yourself you'll stop or avoid doing something, tell yourself you're going to start doing something instead. For example: a resolution to stop sitting around so much becomes a resolution to attend a regular workout class.

Follow-ups with 1,066 participants over 12 months found that 58.9 percent of those with "approach-orientated" goals considered themselves successful a year after making their resolutions, compared with 47.1 percent of those with "avoidance-oriented" goals.

"For example, if your goal is to stop eating sweets in order to lose weight, you will most likely be more successful if you say 'I will eat fruit several times a day' instead," says psychologist Per Carlbring, from Stockholm University in Sweden.

"You then replace sweets with something healthier, which probably means you will lose weight and also keep your resolution."

The volunteers got split up into three separate groups at the beginning: those with no support, those with some support, and those with extra support. In this study, support came in the form of asking a friend or relative for help, and getting advice and helpful materials from the researchers.

It was the people in the second group – the "some support" group – that had the highest level of success in sticking to their resolutions, even more so than those in the third group, who had the most support.

The success rate difference between groups two and three wasn't huge though. The researchers suggest there might be a saturation point as far as support goes, or perhaps differences in the way the third group assessed their level of success.

"It was found that the support given to the participants did not make much of a difference when it came down to how well participants kept their resolutions throughout the year," says Carlbring. "What surprised us were the results on how to phrase your resolution."

The researchers think theirs might well be the biggest, most comprehensive study ever done on New Year's resolutions, and it's something a lot of us will be considering for 2021: almost half the people in the US are likely to make a resolution of some sort for the 12 months that lie ahead.

The new study found that the top resolutions among the participants were around physical health (33 percent), weight loss (20 percent), eating habits (13 percent), personal growth (9 percent) and mental health and sleep (5 percent).

Whether those match your own ideas or you have others, frame them as something to do rather than something to avoid – a strategy that matches up with other research on setting goals. It also helps to use a gradual approach and reward yourself along the way.

"You cannot erase a behaviour, but you can replace it with something else," says Carlbring.

The research has been published in PLOS One.