Just a few years ago, Fitbit was partnering with the likes of designer Tory Burch to make ever-trendier wearables. The fitness tracker was part health tool, part fashion accessory, coming in lots of cute colors, shapes and sizes.

You can still get a designer Fitbit, but the company seems to be moving in a slightly different direction with its recent acquisition of Twine Health, a tiny tech company in Cambridge.

Twine offers a health coaching platform for patients with hypertension and diabetes, tracking their weight, blood sugar, medicine and activity levels.

Andy Palmer was an early investor. But when he found out he had type 2 diabetes a few years ago, he became a user of the platform, too.

"After I was diagnosed, I went to the hospital, and I came home. And I had to see my primary care physician, but it was going to be a few days before I could get an appointment and I didn’t know what to do,” Palmer said.

Then his wife reminded him about the health-coaching platform he was invested in, and Palmer decided to give it a try. Within minutes, he had been set up with Karen, a health coach, who he has now been in touch with nearly every day for three years.

In the beginning, Karen mostly was answering basic questions: how much should Andy eat, and what? What was a normal blood sugar level? Is fruit okay? How about carbs? Karen gave him real-time advice.

This is the whole idea with Twine. We can’t always immediately see our doctor, but Karen is just an instant message away.

“Using Twine, everyday I record my blood sugar, which medicines I take, how much I exercise, and my health coach sees all the same information every single day,” Palmer said.

For Palmer, this accountability is helpful. But Dr. I-Min Lee, a professor of medicine at Harvard, says this doesn’t work for everyone. “I think the health coaching platforms can work well if they are tailored well for different groups of individuals,” Lee said. “It can't be a one-system-fits-everybody.” Some people, she jokes, don't want to know all the day-to-day intricacies of their health. 

She points to research that found that after six months, about a third of the people who bought a Fitbit stopped using it. Other studies found it was more like half. In fact, this slump in the trendiness of wearables might be part of why Fitbit is buying Twine in the first place.

One of the tech company’s founders was Dr. John Moore, who, thanks to this merger, is now Medical Director of Fitbit. He agrees that nothing can be one-size-fits-all, but says it's important — for both patients and doctors — to be able to track results. “The reality is, treatment recommendations don’t work unless people follow through,” Moore said. No matter how diligent patients are, Moore thinks having daily reinforcement is crucial to keeping people on top of managing their health.

"You spend about .1 percent of your time in a year, or less than that, in the doctor's office,” Moore said, “but you spend all the rest of that time out in the world, dealing with the challenges of diabetes or hypertension ... Imagine you have someone there to support you, every day.”

This acquisition makes sense as part of a broader trend, says Alicia Reese, an analyst with Wedbush Securities who follows Fitbit. She says Twine is a HIPPA compliant platform — which means it can be offered to employees through their company's health insurance programs without concerns about privacy.

Reese says Fitbit seems to be moving away from being a hip, colorful thing you wear and towards being a serious health tool. It’s increasingly being used in medical studies. And now, Fitbit and Twine's health coaching tools are going to be marketed to companies, with the idea of keeping employees healthier — and keeping health care costs down for employers.

Dr. Lee thinks, that could be great ... If the platform is flexible enough to fit people's lives.

"I think, you know, we talk about precision medicine ... and it's about genes and what genetic profile you have — but I also think it applies to behavior,” Lee said. “Because not all coaching strategies work for all people."