Fitness wristband maker Jawbone added muscle to its lineup of fitness lifestyle devices Tuesday with a deal to buy the company behind armbands that measure how many calories people are burning.

Jawbone did not disclose financial terms of its deal to purchase BodyMedia, which makes armbands used to track performance of fat-shedding competitors on US reality television show "The Biggest Loser."

The two companies have a combined "three decades worth of deep technology and intellectual property" around sophisticated body sensors and hundreds of patents focused on wearable technology, according to Jawbone.

"There's an enormous appetite for personal data and self-discovery among consumers that will only continue to grow," said Jawbone chief executive and founder Hosain Rahman.

"We look forward to pushing new boundaries, creating new markets, and showing people what's truly possible with wearable computing."

The San Francisco-based company behind "smart" wireless earpieces and Jambox speakers late last year released redesigned its UP wristbands that combine fashion with smartphone lifestyles to help people along paths to improved fitness.

UP wristbands are priced at $129 in the United States. UP applications tailored for Apple or Android mobile devices collect data from the bands to let people more easily get pictures of activity, sleep, eating, and even their moods on any given day or over time.

The wristbands track users' level of activity, whether they are exercising, pacing in an office, or snoozing in bed.

BodyMedia, founded in the Pennsylvania city of Pittsburgh about 14 years ago, is considered a pioneering in combining sensors in wearable devices with machine learning.

BodyMedia armbands track activities of wearers, including how intensely they work out, and calculate how many calories are burned. Sleep and eating information is also gathered.

The BodyMedia platform boasts being registered with the US Food and Drug Administration as a proven device for enhancing weight loss.

By combining forces, "we can make an even bigger impact on people's health and help them achieve their goals," said BodyMedia chief executive Christine Robins.

BodyMedia operations will remain in Pittsburgh but the employees will become part of the Jawbone team, according to Jawbone vice president of strategy Travis Bogard.

"We always talked about wireless headsets as wearable computers," Bogard said.

"This is exactly the long term vision we have had. We are expanding what is possible with sensors and computing going on the body."

Jawbone announced an UP platform that software developers can build on to make applications that work with the wristbands on iPhones, iPads, or iPod touch devices.

Applications ready at launch included RunKeeper and MapMyFitness for logging runs or bicycle rides, including routes, and synching information with UP software on Apple gadgets.