At Geoff Woo's nutrition supplement start-up Nootrobox, almost every employee tracks their blood sugar levels throughout the day.

To his knowledge, none of his 11 colleagues have diabetes.

A doctor on the team, Manuel Lam, helped them get their hands on regulated medical devices called continuous glucose monitors. The equipment, which is made by companies like Dexcom and Medtronic, can cost up to $100 a month for those who would need receive reimbursement for their insurance companies.

For Woo, the expense is worth it. He believes that monitoring his blood sugar trends makes him a better start-up founder, as it helps him optimize his diet to avoid that afternoon slump from blood sugar crashes.

Some of the insights are fairly obvious, such as the blood sugar spike from sugary sodas, but Woo finds that seeing the data is a real motivator to avoid certain foods and beverages.

Blood sugar tracking is a growing trend in Silicon Valley, as hackers look for new ways to feel better and live longer. The fad is closely aligned to the movement around the so-called "ketogenic diet," which involves eating foods high in fat and low in carbs to lose weight and gain energy.

Some scientists are deeply skeptical about blood-sugar tracking for those who do not have diabetes. Such continuous monitoring is primarily geared to those with type 1 diabetes, which afflicts some 3 million people in the U.S. The primary criticism is that it's an expensive hobby and not particularly useful in isolation.

But medical device makers see an opportunity to expand their target market. Dexcom is teaming up with Google 's life sciences arm, Verily, to develop a new class of smaller and cheaper medical devices for the far larger population of people with type 2 diabetes. Such a product might also prove more compelling to those who have pre-diabetes -- 1 in 3 U.S. adults -- and those who aren't at risk for the disease, but are curious about their health.

Likewise, Apple has a team working in Palo Alto on an approach to glucose tracking, which would be both continuous and non-invasive. This technology has eluded life sciences companies for decades. Such a breakthrough would likely be geared towards the broader consumer market, and not just people with type 1 diabetes.

Jeff Dachis, CEO of One Drop, a startup that sells a glucose meter and test strips by subscription, said he's recently noticed a new breed of user that doesn't have diabetes. "It's an interesting opportunity," he said, although he doesn't have immediate plans to develop a specific product for this group.

Other medical experts are optimistic about the interest in blood sugar tracking from those who don't have diabetes.

Samantha Katz, a venture architect at BCG Ventures who formerly worked at Medtronic, has been tracking her glucose levels for years. She initially wore the device to get a sense of the patient experience, but found it surprisingly insightful.

Over time, she has learned how her eating habits and exercise impact her blood sugar. She started making small but meaningful lifestyle changes, like eating nuts alongside sugary fruit, which she claims have made a difference.

"I think there is a lack of awareness about glucose, which is concerning to me because it impacts our bodily systems from weight loss to hormones to cardiac health," she said.