If you were one of the millions of Americans who vowed to live a healthier lifestyle in 2013, you may be edging toward the window of despair. But you probably already knew that.

“We’ve tracked the patterns,” Sue Dissinger, Health and Wellness Director for the YMCA of Greater Charlotte, says of people who vow to improve, “and after 30 to 60 days people start to slowly decline or quit.”

The YMCA’s figures, based on years of study, are echoed by the health and fitness world at large: Despite the best intentions, people tend to lose enthusiasm for a new and healthy lifestyle after about a month of sweating and watching what they eat.

Why does that happen? “We often make our goals too big, too ambitious,” says Lori Stevens, a registered dietician with WakeMed Cary Hospital. “We say, ‘Once the year starts I’m going to cut all sugar out of my diet.’ That’s extreme. It’s not sustainable.”

It’s also not inevitable, this throwing in of the gym towel.

Strategies that will keep you on track:

Revisit your ‘plan’

You do have a plan, don’t you?

“The main reason most people fail is because they don’t have a plan,” says Ronnie Neal, a wellness instructor at Rex Wellness Center of Wakefield in North Raleigh. It needs to be a specific goal, not just “I want to lose weight,” or “I want to get in better shape.” You need both short-term and long-term goals, and you need to be able to visualize those goals.

• Have a realistic goal. Cutting out all sugar, as Stevens noted earlier, isn’t feasible. What is, she says, is vowing to skip dessert on weeknights and indulge only on weekends. “Or instead of saying, ‘I’m going to work out every day and run a marathon in March, say you’ll work out five days a week and do a 5K in April, then maybe a 10K in June and a half-marathon or marathon in the fall.”

• Write down your goal. “Writing down your goals hardwires them a little more into your subconscious,” says Neal.

• Be patient. That malaise you’re starting to feel may be because you noticed quick and immediate results the first two or three weeks of your fitness regimen, but now you aren’t losing weight as fast and the inches aren’t disappearing from your middle as quickly. That’s because your body is hitting a plateau.

You hit a plateau because your metabolism – the process of burning calories for energy – slows as you lose weight, advises the Mayo Clinic. “You burn fewer calories than you did at your heavier weight even doing the same activities, ” Neal says.

Solution? “You gotta change the routine,” says Neal. Your body has adapted to your exercise routine and has become more efficient, burning fewer calories. For instance, suggests Neal, “If you’re doing circuit training, either change the order of your routine or do new exercises altogether.”

• Be really patient. Mixing things up should get you past your first plateau, but it will take longer for your new lifestyle – the more active and healthier-eating you – to become routine. “It takes about five months for a new behavior change” to kick in, says Dissinger.

Track your success

Find a “grading” system that works for you. Numbers work for some people: number of pounds lost, inches off the waist. (But they can also obscure true progress. “I had one client who was upset because he gained two pounds despite losing half an inch around his waist,” says Neal. The two pounds could have been water, Neal tried to explain, adding the real goal was to lose inches.)

Neal sometimes suggests keeping track of progress with a string. “Wrap it around your waist, mark it, hang it up in the bathroom. Three months later, do it again and cut off the amount that you’ve lost.” Those bits of cut-off string can be quite satisfying.

Don’t compare

Don’t judge your progress by the person on the treadmill next to you. “It’s all very individualistic,” Dissinger says. Weight is part of our genetic makeup, and some people need to move more to see results. Experiment and find what works for you.

• Don’t get suckered. If you do get discouraged, it’s tempting to be wooed by those late-night infomercials – by the magic powder that makes it OK to eat half a chocolate cake, or the miracle exercise device that claims to do all the work.

“The biggest issue we have is with the overabundance of information in the media, of fad diets and supplements that claim to fix everything,” says Stevens. “It can be confusing and overwhelming.”

Alas, she advises, saying what you likely already know, “There is no quick fix, no magic pill.” Better health is, in the long term, about a healthier lifestyle.