Fitbit wants to make it easier to stick your fitness plan.

Known for its wearable activity trackers, the company is launching a new platform called Fitbit Care that offers personalized coaching to help users stay on track with their fitness plans, lose weight and manage chronic diseases, Fitbit announced Tuesday. Users can download a special app, Fitbit Plus, that pulls health data from sources like a Fitbit or blood pressure monitor.

Though Fitbit sells most of its devices directly to consumers, it's targeting health plans, employers and hospitals with the new service. Health insurer Humana, which has been offering Fitbits to some of its members since 2013, is already signing up people for Fitbit Care as its preferred solution for health coaching.

With the new system, Fitbit aims to solve for two of the most vexing challenges in modern medicine: changing people's behavior and lowering health-care costs. If successful, Fitbit could grow its enterprise health business, possibly helping to fend off competition from Apple, which has been adding more health features to its smartwatch.

"We're already seeing proof points that the solutions we're building are taking hold and are resonating with our health plan and employer customers," said Adam Pelligrini, general manager of Fitbit Health Solutions.

Fitbit acquired health coaching platform Twine Health in February as part of its strategy to add more health services. The new Fitbit Care system essentially pulls various parts of the two businesses and combines them into one integrated service.

Users that already have health coaches, diabetes educators or trainers can connect with them on the platform. They can also opt for "a fully wrapped solution" where Fitbit provides the technology and wellness advice. Fitbit's coaching can focus on disease prevention, managing chronic conditions or more complex care, said Dr. John Moore, medical director at Fitbit.

Once patients receive medical treatment, "getting the support they need to be successful in changing behavior is really the struggle," said Moore, who's also the founder and former CEO of Twine Health. "They run into roadblocks and there's incredibly high friction for them to get the support that they need to succeed on that day-to-day journey."

Health-care costs pose a challenge to both employers who are covering them and employees whose contributions make up a larger percent of their paychecks. A platform that could help employees with conditions like obesity, diabetes and heart disease — and the costs associated with them — could find a receptive audience in employees.

Fitbit already works with more than 100 health plans, including Blue Cross Blue Shield, Humana and UnitedHealth Group. Fitbit's health solutions business unit currently represents less than 10 percent of the company's overall revenue, Pelligrini said.

With the expanded Humana partnership, Fitbit's coaching and wellness solution may be available to more than 5 million Humana members. Fitbit executives declined to comment on how many people will have access to the coaching service or to say how much it will cost.

Focusing on employers also could help Fitbit as it faces pressure in the consumer market from the Apple Watch. Apple continues adding more health features to its smartwatch, most recently an electrocardiogram sensor, which measures the heart's rhythm.

"As Apple incrementally adds new and, I would argue differentiated features, I think it will be increasingly hard for companies to compete unless they come up with something that's dramatically different," said Patrick Moorhead, president and principal analyst at Moor Insights and Strategy.

Ramon Llamas, research director with IDC's devices and displays team, said the platform is unlike anything he has seen from Fitbit before. He thinks combining all of Fitbit's features into a one-stop-shop is "rather compelling."

"If there's one thing we notice about health and health improvements, it's that having an ecosystem of supporters coming from different areas helps make it all happen," he said. "That's what Fitbit is attempting to do here."