Want to keep that new year's gym resolution? Try CrossFit: Data

Here's what we know: Going to the gym is a top resolution every year —and most people fail at keeping it, at least for the long run.

According to new data from data intelligence firm Cardlytics, 46 percent of new gym customers drop off by the end of January, and nearly 80 percent of them give up entirely by the fourth quarter. However, it turns out that the type of gym can make a difference in how long it takes for new gym-goers to give up.

Among specialty workout choices, new yoga clients have the highest drop-off rate, with a full 70 percent leaving after the first month. Yet CrossFit members are about twice as likely to stick it out until February or the end of the year, Cardlytics figures show.

Read MoreHow SoulCycle became a cult-like fitness sensation

The extreme fitness craze has both ardent enthusiasts and its share of detractors. However, proponents swear by its benefits.

"It's the culture and the sense of community," said Ian Albert, manager of CrossFit Concrete Jungle in New York City. "CrossFit gyms hold you accountable and will check in on you if you don't show up. It's not a huge membership, so we notice if somebody is not coming in," Albert said.

"CrossFit members have more motivation to show up because of the community, the cheering and high-fiving, and camaraderie," he added. "It's more fun to workout with other people that know you."

Cardlytics' partners include Bank of America and Lloyds Banking Group. The company has transaction data from more than 85 million U.S. bank accounts, allowing it to deliver accurate information to retailers about customer behavior.

These details can be powerful for retailers and advertisers. For example, the company knows that people who sign up for spinning classes are 50 percent less likely to buy fast food, as compared to the average gym-goer.

This kind of information helps companies decide which customers are worth marketing toward, and what strategies would be best. It wouldn't be the best idea to pay for an ad offering a 2-for-1 discount on cheeseburgers to somebody who spins. That would be the wrong audience.

The best performance overall comes from the mass market, big-box gyms now often described "Globo Gyms" — a reference to the movie "Dodgeball."

One publicly traded example is Planet Fitness. Even if the numbers are relatively low, these gyms can bring in the most customers by the end of the year, as compared to other gym types.

Of course, the data are based on purchases, not necessarily attendance. Luckily, it's memberships and not necessarily attendance that matters for gym finances.

According to Planet Money, the best case economic scenario for many gyms is to have most of their paying customers never show up, because some gyms have far too little space to accommodate all the potential exercisers paying for access.

Gyms know that attendance and membership boom at the beginning of the year, then peter off. For the "Globo" outfits like Gold's Gym, the first month of the year can bring a traffic boost of 40 percent. According to a 2015 report by health club trade group IHRSA, about 12 percent of all health club memberships (including those with tennis courts and swimming pools) are purchased in January, compared to about 7 to 9 percent in other months.

Businesses often try to cash in on New Year's resolutions by offering introductory deals and selling annual memberships. That way, even after you give up on that resolution, the gym can stay afloat until New Year's Day comes around again.

According to Cardlytics' credit card data, full gyms have far more yearly subscribers than other types of gyms, but they still only make up 1 percent of customers for full gyms, 0.1 percent for yoga studios and 0.4 percent for CrossFit. For brands like SoulCycle and FlyWheel — the main brands in the spinning category — customers tend to pay for classes as they go. That may make it harder to maintain revenues from new customers throughout the year.

"Our review of 2014 fitness spend identified an opportunity for yoga and barre studios to target consumers beyond February to help bring them back as customers," said Dani Cushion, chief marketing officer at Cardlytics. "With the Cardlytics platform, these retailers can easily target those lapsed customers and bring them back into the fold."