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This former SpaceX engineer wants to prevent you from getting diabetes

Josh Clemente’s Levels just raised another $38 million to fight metabolic health—and stave off the $327 billion spent annually on the effects of diabetes.

[Source photo: Levels]

Josh Clemente was only 28 years old, but he was extraordinarily tired. He was, by all metrics, healthy. Yet he was convinced he had a terminal illness. Unfortunately, his doctor told him that his blood work revealed only a niggling vitamin D deficiency.

He decided that he wanted to better understand his relationship to sugar. After making his fingers black and blue with finger-prick blood tests, a book called Wired to Eat led him to something called a continuous glucose monitor (CGM) that could give him a real-time feed of his blood sugar levels. This seemed like a much better option.

But Clemente couldn’t get his doctor to prescribe him one because he wasn’t diabetic, the only population that used these devices. Instead, he had a friend get him one in Australia, where they’re available over the counter.

Josh Clemente [Photo: courtesy of Levels]

His first meal while using the device was a fat bowl of brown rice with avocado, green peppers, and lettuce. He was eating vegan at the time and trying to maintain his muscle mass. “I was like, this is gonna be the perfect meal,” he says. And then, something unexpected happened. “My blood sugar hit 200 in like 20 minutes. That was the moment when I was like, holy smokes.”For the uninitiated, 200 milligrams per deciliter (mg/DL) is very high. Ideal blood sugar levels are between 75 and 120. Two hours later, Clemente started to feel pangs of irritability, and he could feel his body dragging. This was the fatigue that had been making him miserable. He checked his blood sugar.

“I was plummeting,” he says. “I’m seeing all the dots connect on a curve and it was magic for me.”

He was experiencing reactive hypoglycemia, a condition in which the body releases too much insulin to break down a carbohydrate-heavy meal. This dysregulated response is more common among the one in ten Americans with diabetes. But another third of Americans are prediabetic, likely unaware that they are possibly suffering the same fatigue as Clemente. Constant blood sugar monitoring via a CGM is at the forefront of diabetes care, showing patients how the way they eat can lead to elevated levels of sugar in their system.

Clemente’s epiphany led him to start Levels, one of several startups that have emerged to bring continuous glucose monitoring to people who are not diabetic but either are prediabetic or concerned that their lifestyle puts them at risk. What’s notable is that these companies aren’t reinventing the CGM itself—those are still made by the pharmaceutical companies Abbott and Dexcom—but rather giving the Silicon Valley treatment to this clunky piece of medical equipment and its stream of glucose data. Levels (as well as rivals such as Supersapiens, January AI, Signos, and NutriSense) add a sleek app with crisp charts and health scores, as well as a recurring-revenue business model, to educate otherwise healthy people and help them get a handle on their diet and lifestyle before they become diabetic.

But Levels appears to have the most momentum. Some 24,000 users have flowed through the platform since it opened up its private beta in January 2021; 200,000 people have joined its waitlist. On Instagram, 90,000 people—a mix of trainers, nutritionists, wellness experts, and regular folks—follow Levels to get insight into the frustrating world of dieting. It also has a blog and podcast.

The company has attracted an impressive set of investors, including Andreessen Horowitz, which led its most recent funding round. This week the company announced a $38 million Series A, including $5 million from 1,400 of its users, at a $300 million valuation, bringing its total funding to $50 million.

Now Levels must prove that its platform is truly life-changing, that its service is for more than tech-world biohackers and early adopters, and that it can make a dent in the chronic and expensive problem of diabetes. The Centers for Disease Control and Prevention has estimated that diabetes costs the U.S. $327 billion in medical bills and lost productivity annually. One dollar out of every four spent on healthcare in the United States goes to treating people with the disease. Every statistic reveals the awesome nature of the challenge: Some 42% of American adults and 19% of children are obese, putting them at risk for chronic conditions such as diabetes and heart disease.

“Any control system has data monitoring associated with it,” Clemente says. “You have to be constantly monitoring whether the controls are working and how the system’s responding.” But the healthcare industry, he notes, is too preoccupied with symptom treatment and diagnosis. To improve health—really, to optimize health—people need to be able to see their health data and take actionable steps. That’s where Levels comes in.

The idea that a tech startup is going to fix everything associated with diabetes via an app borders on self-parody. But Clemente has some experience with doing what had once been thought impossible.


Clemente came to the idea for Levels while he was working as an engineer at SpaceX, a job he secured by building out his senior engineering thesis: an all-terrain rescue dune buggy with four-wheel steering. In 2016, he was working on an oxygen breathing system (which would ultimately be used when SpaceX sent the first commercial crew of astronauts into orbit in 2021), which led him to some research on oxygen toxicity. He learned, from several studies by a researcher in South Florida, that mice in ketosis, whose bodies were burning fat instead of carbohydrates, were able to stave off oxygen toxicity five times longer.

He had always believed that all calories were equal, that nutrition didn’t have a meaningful bearing on how humans exist. “This was the first time I had seen something that said actually just a simple change in where those units of energy are coming from completely changes the physiologic nature of this creature,” Clemente said on an early episode of his company’s podcast, A Whole New Level, an audio chronicle of Levels’s origins and development, which has an air of presumption about its future success.

[Photo: courtesy of Levels]

At SpaceX, he worked 50- to 60-hour stints, sometimes catching a nap under his desk. When he wasn’t at work, he would do CrossFit, which involves high-intensity interval training. Under this strain, his body was burning out. The studies got him thinking: “I would like to make sure that I’m optimizing myself for superpowers, if that’s possible, just by eating the right foods,” as he said in episode 2 of the podcast (“From Selling Cars to Building Rockets”).

That’s what led to his blood-sugar monitoring. When he showed his doctor how his glucose would spike throughout the day, the physician confirmed that Clemente was likely prediabetic. But his prescription was bland: Exercise more and eat better.

Clemente was also frustrated by the experience of tracking his data on the CGM. He had to carry around this little device with a screen showing a graph of his blood sugar. He would then manually enter his levels into a spreadsheet so he could keep track. What he wanted was an app that did this for him. He wanted the Garmin of CGMs.

Growing up, Clemente was homeschooled. By his own account, he taught himself to solve problems by reading textbooks and then reverse engineering the problems at the end of each chapter. Likewise, when he decided that he was going to build a business around CGMs, he went to the source first: doctors. He knew that to make CGMs available broadly, he would need a network of physicians who could prescribe them.

Months later, he had failed to secure a single relationship. In June 2018, he commiserated with a friend, Sam Corcos, about the difficulties he was having with his startup idea. Corcos, a serial entrepreneur and engineer by training, liked the CGM idea. But he had a different notion about where Clemente should start. He needed investors first, not doctors.


When Corcos and Clemente chatted, Corcos was looking for his next venture. It had been about a year since he had left the third startup he’d cofounded, a concierge automotive startup called CarDash (it was acquired in 2020). He immediately introduced Clemente to his network.

Their first investor meeting proved auspicious. Before the meeting, Clemente had bought a “health drink” from a smoothie cart. It had apples, carrots, and celery in it. He slurped it down, sipping it as he presented the idea of CGMs for all. The initial idea was to sell CGMs to health-oriented communities like CrossFit.

Thirty minutes into the pitch, Clemente scanned his blood sugar to show his would-be backer, Moshe Lifschitz, who was at U.S. Investments at the time. He was spiking at 217 (a typical blood sugar level is around 80 or 90). What Lifschitz and his colleagues saw across from them was a beacon of health: a young CrossFit trainer drinking a health drink. What they saw on Clemente’s device was a person with out-of-control blood sugar. Suddenly they were all in on CGMs. They wanted one. They also wanted one for their kids, their wife, their friends. Lifschitz said that he would invest if Clemente could get Corcos to join the company.

[Photos: courtesy of Levels]

In Levels lore, this moment is known as the “Juice Cart Incident” (episode 4). It is the moment the company became real. A few days and 50 or so emails afterward, Clemente and Corcos met again. “I think the first sentence was like, ‘Hey, how you doing? I want to do this with you, but I need to be the CEO,’” Clemente says. “In the moment it felt like a hostile takeover of some kind.”This bluntness is a key feature of Corcos’s personality and has come to inform the tone and direction of the company. Unequivocally, he had more experience than Clemente, but that didn’t make the ask any less bold. Initially, Clemente bristled, but after talking it through decided that while the concept for the startup was his, being CEO might not be his strength. He was good at logistics and problem solving. So he agreed to let Corcos take the helm.

Corcos came up with the name Levels—they were measuring people’s levels, after all—and he and Clemente incorporated the company on June 24, 2019. Within a month, they had $500,000 in the bank. Corcos prioritized building a small team to develop an app. They also hired Dr. Casey Means, first as a consultant and later as chief medical officer, to build content. Means quickly convinced Truepill, a digital pharmacy and physician network, to prescribe and distribute CGMs for Levels. This enabled the company to start selling in the beginning of 2020.

But they also needed more money. The world was at the very beginning of a pandemic. Because they could not woo investors in person, Clemente and his colleagues decided to be extremely transparent with investors about their early progress. Then in the spring, Andreessen Horowitz (a16z) led a $12 million funding round in Levels.

Vijay Pande, general partner at Andreessen Horowitz, says he was compelled by the company’s approach to keeping people healthy as compared to traditional healthcare. When he tried Levels, he was prediabetic. Through using a CGM, Pande found out that he couldn’t have white or brown rice, but he could eat ice cream without spiking his blood sugar. “The carrot here,” he says, “is not the carrot but the ice cream.”


In May 2021, in preparation for what was supposed to be a hot vax summer, I decided to try Levels. Like many people, I had gained weight during the pandemic and was eager to shed pounds. After spending far too many hours preparing myself to staple Abbott’s FreeStyle Libre glucometer to my arm, I shut my eyes tight and quickly pressed the white dome against my skin. It was done. “It took me three hours the first time I did it,” says Means, who motivated herself with Kanye West songs, “and I’m like, this is my company.”

The Levels experience still requires a lot of work from the user. Levels doesn’t directly integrate with the CGM, so I have to scan using Abbott’s app, which shows me my blood glucose level and a graph of the last hour or so of its readings. Then I have to open Levels, which charts my changing blood glucose throughout the day and appends activities, like eating or working out, to every change. My overall rate was on the lower side, 75 to 85 mg/DL. At first, I seemed to be doing great. I had a score of 100, which meant my levels were within a good range and stable.

[Photos: courtesy of Levels]

Later that day, though, I spiked. My dinner—steak tacos with avocado and chipotle sauce on blue corn tortillas—sent my blood sugar up 45 mg/DL. In addition to blood glucose tracking, Levels asks members to enter their meal intake manually. You take a picture and write a brief description, in an effort to identify what caused the spike. It also rates your meal based on your glucose response (my steak tacos were an abysmal 5 out of 10).

The following day I tried those tortillas again, this time for breakfast with eggs. No spike, a 10/10 meal. I had steak tacos for dinner again a few days later—but without the chipotle sauce. No spike: I had found the offender. That chipotle sauce had honey in it. Inside the app, you can compare meals against one another if the menacing agent isn’t so obvious.

My four weeks wearing a CGM and using Levels revealed several insights. One, oat milk has an incredible amount of sugar in it. An oat milk latte sent my sugar soaring. When I checked the label on a carton of oat milk at the grocery store, I saw it had 20 grams of sugar per serving; whole milk, by comparison, contains 11 grams per cup. This discovery basically ruined oat milk lattes for me, which is sad, because I’m lactose intolerant.

The other interesting bit is that sometimes my glucose would spike after workouts, specifically high-intensity interval training sessions. In the app, Levels served me an article on this very phenomenon. Strenuous workouts, it says, kick off a chain reaction wherein the liver releases a form of stored glucose into the bloodstream, providing fuel for the workout. HIIT workouts are associated with better glucose metabolism and insulin activity. Levels’s app let me log workouts, so it knows when a spike is related to food versus activity. It also integrates with such devices as Apple Watch and Fitbit to record workouts automatically.

While I did learn how my body responds to certain foods, I found that Levels also falls victim to the same gamification that can make apps sticky. Levels’s scoring system triggered my competitive nature, and I was keen to keep eating meals that led to higher scores, rather than experimenting with foods that would lead to big spikes. White rice produced a spike, but homemade french fries raised my glucose only moderately. The same was true for a Popeye’s fried chicken sandwich (7/10), which seems bonkers. Still, I avoided these foods, because I wanted to keep getting those 10-out-of-10 meals.

[Photos: courtesy of Levels]

While that sounds good, during the time that I was using a GCM and Levels, I was also tracking my meals in MyFitnessPal and counting calories, fat, protein, and carbohydrates. I found that I was eating a lot of fat. That wouldn’t necessarily be an issue if I were on a keto diet, but I wasn’t. In its articles, Levels aggressively targets oats as bad, a food many doctors insist is heart healthy. I had more data, and I lost a few pounds. But I wasn’t sure if the diet I was eating was actually healthy.“You could drink vodka and canola oil and have great glucose for a while and probably not be super healthy,” Clemente says. This is at least part of the reason the company added a metabolic health panel to its offerings last month. The $179 blood test delivers a readout of total cholesterol, triglycerides, both high- and low-density lipoprotein or LDL, as well as fasting insulin, fasting glucose, hemoglobin A1C, and C-reactive protein (a marker for inflammation in the body). “This tells you whether you’re burning fat, how much fat is in the bloodstream, and whether it’s responding to meals,” Clemente explains.

For some outside perspective, I contacted Dr. Osama Hamdy, medical director at the Joslin Diabetes Center. “[CGM] is the best tool that has ever been used for diabetes,” Hamdy says, noting that last year the center started giving everyone in the weight-management program a CGM regardless of whether they had diabetes or even prediabetes. “They see the robust impact of exercise and a healthy diet on their blood glucose level,” he says.

But Hamdy is quick to add that the CGM is not everything. People at his center, he notes, still need personalized nutrition, an exercise plan, and a behavior modification plan (and sometimes medication) in order to achieve better health. However, he does see value in using a CGM to shape a person’s diet, maybe over a couple of weeks, to figure out which foods spike their blood sugar most.

According to Hamdy, the future is a noninvasive CGM, a device that doesn’t require a needle prick. “[Noninvasive CGMs] are inaccurate now,” he says. “But in general, even if it is inaccurate, it’ll give you a trend of how the blood sugar is moving and what the average will look like. . . . The average is almost accurate.”

Today, the only noninvasive CGM on the market is Nemaura Medical’s sugarBeat, a daily Bluetooth-enabled stick-on device that measures blood glucose from the top layer of skin. Rockley Photonics is now working on commercializing its noninvasive blood glucose reader through a partnership with Medtronic. Rockley already makes sensors for Apple devices, and Apple is reportedly interested in developing a blood glucose reader for its Watch.

What would it mean for Levels if Apple, famous for its excellent user experience, were to launch blood sugar monitoring? “We wrote a premortem a few months ago, and one of the line items in the premortem was that Apple could crack noninvasive monitoring and just sweep the market off its feet,” Clemente says. “And that’s totally true. It still remains true.”


It has been almost a year since I tried Levels, and the product is still in beta. Corcos is hoping to launch officially in June, but first he wants to get the business model right. “One of the main reasons why we haven’t started scaling yet is once you lock in your business model, you basically can’t change it,” he says.

Levels’s latest funding comes on the heels of a pivot for the company that seeks to address one of the major issues Hamdy raised: There’s value in using a CGM for a short period to see what spikes your blood sugar, but a company can’t build a sustainable business off a short-term trial. Levels had offered a subscription-based model, but has now shifted to an annual membership, inspired by Costco. For $200 a year, the company will offer members use of its app, content, and access to its services, including a nutritionist, at-home blood tests, and CGMs. The products and services have separate pricing, but will be sold at cost. The membership model also wards off the temptation to make money advertising against all of Levels’s content.

Corcos wants to build user trust, and in order to get it, Levels cannot rely on ads or constantly hawking CGMs. “I want to be in a position where I can tell you, honestly, we recommend doing these tests quarterly. We recommend doing these tests annually, and I don’t actually care if you do them, ’cause I don’t make any money on this,” he says. “I’m just telling you ’cause it’s medically valid.”

[Photo: courtesy of Levels]

With the membership model in place, Levels’s product focus this year is to fill out its app’s home screen, also known as the “Now” page, where Levels serves up content and advice based on glucose trends. When a person is not wearing a glucose monitor, the page is blank aside from Levels’s list of services. Corcos wants this screen to tell people what actions they can be taking even when they’re not monitoring their glucose.The company is also embracing medicine, another turn away from the early days of Levels, when it shied away in part out of fear of regulation that could slow progress. Levels already offers an at-home blood test that will tell users their total cholesterol, blood glucose, and other health metrics—similar to what one gets at an annual doctor’s visit. It also now has nutritionists on the platform that users can work with for a range of prices depending on the package (one nutritionist offers five sessions for $525). Levels is exploring building its own health sensor that would track a variety of health metrics—not just glucose. Building its own hardware has not been ruled out.

Above all, Levels is striving to make it easy for people to understand viscerally that changes they make to their diet have an impact on their overall health. “In many ways, Levels will be what Apple’s HealthKit wants to be but can’t for a variety of internal reasons at Apple,” company executives wrote in an internal document titled “Product Vision.”

Tellingly, Levels recently hired Maziar Brumand, who previously led strategic health initiatives at Apple, to be its head of business. It also brought on Taylor Sittler, cofounder of the genomics company Color, to lead research and develop clinical validation. The company is planning several large-scale validation studies to prove that its app, paired with a CGM, can meaningfully shift health outcomes for users.

These studies may also make the case to insurers that they should pay for all or some of Levels. Getting insurers on board will also shift Levels from a niche health product for rich people to something broader and more accessible. “It’s still an open question as to whether there’s a huge consumer market for this,” Corcos tells me via email after our last interview. “But we’re going to find out :)”


Ruth Reader is a writer for Fast Company. She covers the intersection of health and technology. More

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