NEW YORK (Reuters) - People seeking to get or stay fit in 2015 might do better to start today rather than rely on a New Year’s resolution to shape up tomorrow, fitness experts say.

Losing weight and getting fit and healthy are among the top five resolutions every year, even though most of winter’s great expectations wither by spring.

“The New Year’s resolution is a kind of grand, glorified, long-term goal that people, for societal reasons, tend to begin on the first day of the calendar year,” said Gregory Chertok, a sports psychology consultant with the American College of Sports Medicine. Goals set because people feel they should make them tend to be pressure-filled, unrealistic and less likely to be accomplished, he says.

“‘I’d like to cut down on junk food a little bit,’ is a goal more likely to be accomplished than ‘I’ll completely revamp my lifestyle,’ which is the kind of goal we set as a New Year’s resolutions,” Chertok said.

While about 45 percent of Americans make New Year’s resolutions, only about 8 percent succeed, according to a University of Scranton study published in the Journal of Clinical Psychology.

Dr. Michele Olson, professor of exercise science at Auburn University Montgomery said a resolution can be a way of putting off what can be done today.

“If there is a fitness need, such as to increase strength or decrease body fat, I say, ‘Let’s make a plan now,’” Olson said, adding that what is essential is to set a long-term plan with short-term goals.

“This is why athletes stay in shape year-round. They have a program scheduled and planned over an entire year with variation, rest days, more-intense and less-intense workout periods,” she said. “It’s like one’s job: there’s very little vacation time.”

Dr. Cedric X. Bryant, chief science officer of the American Council on Exercise, said the New Year may be the worst time to make a lifestyle change.

“For many it’s the busiest, most hectic time,” he said, “and most people have an all-or-nothing mentality.” Bryant said people who succeed focus on progress, not perfection, and plan for the inevitable slip-up.

“People don’t take time to celebrate the little successes,” he said. “Because they’re so focused on, say, an arbitrary weight goal, they don’t notice that they are sleeping better or feeling less anxious.”

Chertok suggests setting goals that don’t depend on the calendar to achieve the best results.

By Dorene Internicola

(Editing by Paticia Reaney and Dan Grebler)