How Your Metabolism Really Works (with Josh Clemente)

I had always been the type person. It’s like I can outwork any diet. I’m a machine. As long as I have the right mindset, I’ll be able to go without sleep and I’ll be able to manage my stress levels. That’s for other people to worry about.

Welcome to the “BarBend Podcast,” where we talk to the smartest athletes, coaches, and minds from around the world of strength. I’m your host, David Thomas Tao, and this podcast is presented by barbend.com. Today, I’m talking to Josh Clemente, Founder and President of Levels.

A company producing wearable tech, so users can track blood-glucose in real-time to maximize diet and exercise results. It’s a relatively new company, but after a $12 million fundraising round, they’re already in use by top pro athletes and are even making waves in the strength sports community.

Josh is a veteran of both SpaceX and Hyperloop One, and his background is in designing life support systems for the next generation of space exploration.

In today’s episode, we discuss how that work inspired Josh to find Levels. Why metabolic responses can vary so differently from one person to the next, even with the same food? What this means for actionable insights into strength and performance?

I do want to take a second to say, we’re incredibly thankful that you listen to this podcast. If you haven’t already, be sure to leave a rating and review of the BarBend Podcast in your app of choice. Now let’s get to it.

Josh, thanks so much for joining us today. The question that I want to ask you, and it’s the first time I’ve ever been able to ask anyone in the world, this question. How do you go from rocket science to glucose monitoring? Maybe give us a little background as to how you got from point A to point B there?

David, thanks for having me on the show, first of all. To your question, it’s a very good one, but it was through personal experimentation and lifelong interest or curiosity about things I don’t already know. That led me into how machines work throughout childhood and just tooling around in the garage trying to stay out of chores.

I became fascinated with machines and mechanisms and that led to a mechanical engineering degree. A job at SpaceX, eventually leading the pressurized life support system team working on the astronaut program. SpaceX recently flew four astronauts to the International Space Station earlier this year. The first launch of that Crew Dragon vehicle.

What I was able to work on was the pressurized breathing apparatus. The systems that feed oxygen and purified air into the cabin, into the spacesuits, clean contaminants out, extinguish fires. That program was the last big push in my six years there at SpaceX.

During that time, I actually reached a point where I had to come to grips with the fact that I was burning out mentally and physically. I had hit a wall, it felt like, where I could not continue to perform at the level that I expected of myself day to day.

It felt very strange because I thought I was doing everything right to set myself up to be a high performer.

This was throughout my career, also, being on the side, a fitness freak and a CrossFit Level 2 trainer. Somebody who pushes hard in the gym assumes that if I’m doing all the things, sticking to my workout regimen, and have low body fat, can run fast, lift heavy weights, then I’m healthy.

Having that juxtaposed with the reality of my day-to-day which was no energy, low mood, just dragging myself through the day, and not performing to the degree that I want, it led me to start deciding, “OK, I’ve got to do something about this. I need better information about what choices I should be making because clearly the ones I am making are not enough.”

That caused a little bit of side research to happen. This was just experimenting with fuel systems. Where does our energy come from? That’s, of course, metabolism, which is how every cell in our bodies produce energy from our food and environment. The number one molecule for energy in the modern human is glucose. I was like, “OK, I’ll start pricking my finger and measuring glucose.”

That was how it started. Didn’t lead very far. Eventually, I read about this new technology called Continuous Glucose Monitoring. I tried to get one, was turned down by my doctor because I wasn’t diabetic. When I did eventually get one, I found out that after about two weeks of data, I was either borderline or full blown pre-diabetic.

That was the last straw where I realized, “OK, this is crazy.” I had no idea and no indication, don’t have any outward appearance that would cause me to think that something was going wrong. All of my underlying manifestation of this metabolic dysfunction was my quality of life, my day-to-day experience. I started from there on the Levels journey.

It’s fascinating to me that this fitness industry has been — and I’m preaching to the choir here, but this is a setup for a question, I promise — It’s fascinating to me the fitness industry has been obsessed with cracking the wearables code for so long.

Going back decades with the advent of smartwatches, with devices that measure things like HRV and blood pressure, we hear about wearables. It’s often times focused on the physical signs of output, or energy expenditure as measured by work output, work capacity. Pedometers being the base-level of that. They’ve since got much more advanced.

Wearables in the fitness industry haven’t really focused on the chemical interactions in our body, or at least measuring that. Everything’s been measuring the output but the fuel going in, we haven’t measured that. Why do you think that the industry has been so slow to adopt or to introduce fitness wearables that do focus on chemical aspects of performance?

Really great question. We’re referring to this new future era that we’re a part of right now, as the bio-wearables. This is stepping from the superficial factors that you can measure yourself, the pedometer, the Pulse, to actually measuring molecules in our biology.

Part of the reason…There’s twofold reasons. One is that, historically this has been very hard to do. There’s a specific reason that the continuous glucose monitor is what it is today. That’s for the management of diabetes.

It was originally a lab technology. People who have diabetes have an acute need to know their blood sugar. It basically made the business case for companies to develop convenient technology that can be worn full time and can stream wireless data to your phone to tell you what your glucose is.

The rationale there was for people with type 1 and type 2 diabetes to be on top of their medications as necessary. The beauty of it is that everyone who is alive has a metabolism. The factors that lead to metabolic breakdown, specifically type 2 diabetes, but even prior to that the metabolic dysfunction.

I was experiencing energy issues, crashes, reactive hypoglycaemia, weight gain, mood dysfunction. All of these things are actually energetic at the foundational level. That same technology can now be reapplied to the pre-diagnostic space.

It’s like the factors had to come together, microelectronics revolution had to happen, affordability had to happen. There had to be resources needed to be allocated to this to make the technology possible. Then when that happened, when those resources were applied, it was in the medical device field.

It’s heavily regulated. It takes a lot of money and a lot of time and determination to get a new device to market. It’s not the ideal space for a consumer product. The factors aren’t quite there. That’s what we’re dealing with right now is reallocating this firmly therapeutic device into the world of wellness and fitness.

It’s going to be the bow wave. We’re going to break open this new space. It’s going to really transform over the next few years. We’ll see many more molecules being measured.

One thing I can tell immediately talking to you for just a few minutes is that you like trying difficult things. Whether it’s personally and being very quantified about your own health and wellness or trying to crack into a or break into a very difficult space. It’s something we’ve talked about on the podcast before.

I will say you’re actually not the first former rocket scientists we’ve talked to on this podcast. We had Brandon Heavey, who worked at the Jet Propulsion Lab on the podcast well over a year ago. There’s a trend there…

…people who like breaking these things down and asking big questions in the fitness space. I do want to talk a little bit more about your personal journey. As you were first experimenting with glucose monitoring yourself. You found out that you were actually experiencing some signs of pre-diabetes.

Obviously, this is not a medical advice podcast, but I’m curious what changes that might have triggered in your own approach to wellness training and nutrition?

Great question. By the way, Brandon Heavey, I was just on his show, “Strength & Scotch.” He’s a great guy. We fall in the same circle, very cool.

That’s a fun…If you haven’t listened to it. If you listen to the BarBend podcast, but you don’t listen to Strength & Scotch, do yourself a favor they’re like us, but more fun.

TBD. Great guys. As it relates to my own experience, and this is what was so fascinating is that we traditionally look at metabolic health as binary. It’s like you’re healthy. Then something happens to you and you’re not healthy any more.

Most people ask that question is like, “When you’re talking about metabolism, am I metabolically healthy?” What we’re needing to do is reframe this entire conversation. It’s not binary.

We all live on the spectrum of metabolic function. That’s called metabolic fitness. The same way we go into the gym, and we train our strength through focus, effort, and repetition. That applies to all of the lifestyle choices we’re making throughout the day, which build into a hormonal environment, a chemical environment in our bodies that determine whether or not we’re functioning properly.

For me, throughout my life, I’ve been focusing on the physical fitness piece, been focusing on strength and conditioning, putting up big weight, running fast, those were my metrics for health. It’s important for sure. There are several other levers. Those are sleep, stress control, and nutrition. I had never paid enough attention there.

I had always been the type of person’s like, “I can outwork any diet. I’m a machine. As long as I have the right mindset, I’ll be able to go without sleep. I’ll be able to manage my stress levels. That’s for other people to worry about.” The realization that I had with CGM extended well beyond the foods I was eating to the environment I was building for myself.

I realized that by watching how my body responded, the value of sleep specifically. Going from, let’s say, a red-eye flight, jumping off and going straight to work and working a 16-hour day. Seeing how my body responded to something like that, which was to say disastrously blood sugar elevated fasting level in a dangerous borderline pre-diabetic or pre-diabetic zone.

Every meal I ate, major blood sugar elevations, and shortly thereafter, reactive crashes, horrible energy dysfunction, needing tons of coffee versus stringing together multiple days of high quality, eight hours of restful sleep, shutting down, winding down before asleep, not going straight from email into bed.

Seeing how dramatic the difference was, the quality of sleeping being at stake was totally mind-blowing to me. It really drove home that this science, it’s legitimate and applies to me, and stress.

[laughs] I have had a stressful meeting where without eating anything, I’m sitting there, my blood sugar has gone into a pre-diabetic state, a post-meal pre-diabetic zone, by basically the cortisol that is flooding my system and creating a fight or flight scenario.

Cortisol, it’s a hormone that falls into the glucocorticoid territory. It tells the liver, “You’re in danger. You need to produce a ton of energy to escape this.” Your liver starts flooding your system with blood sugar.

What’s fascinating about that is that in the gym this is exceptional. It’s going to give you all the fuel you need for your muscles to function properly and get that workout done. When you’re sitting at a desk and stressing out about emails or stressing out about that complex project you’re working on day after day, this is creating hormonal mayhem.

This is what was happening to me. I was working crazy, stressful environment and not sleeping well. Those were the factors that were dominating my life. Add into that the fact that I was guiding my nutrition based on the Internet and based on friends at the gym whatever was working for them, I was doing that.

It was not at all nuanced. It wasn’t formulated for me. I was eating hundreds of grams of carbohydrates thinking I needed to replenish glycogen or carb load for a workout. I was causing these huge blood sugar elevations and dealing with the hormonal consequences thereafter.

Seeing all this stuff in real time from my body in front of my face, it led to embracing mindfulness breathing techniques, stress management, sleep hygiene, seven to nine hours of sleep at all costs. Then de-emphasizing workout specifically in favor of a balanced recovery and workout scheme, and then of course, nutrition changes.

I’m curious about on the nutritional side obviously. There are a lot of buzzwords people have heard on this podcast before. If you’re a BarBend reader as well, we’ve covered some of that. It can be tough to keep up on the science. It can be very difficult, from a content producer’s perspective to separate science from fad.

Just because a lot of people are interested in something a particular dietary trend does not mean there’s evidence to necessarily support it. The two do not necessarily go hand-in-hand. The Internet has exacerbated that in a big way.

I’m curious what your personal, and again, it’s your personal thing. As you mentioned, this is not carte blanche for everyone to say this will work the same way for every person. What is your current dietary framework? Are you incorporating fasting anything like that? How would you describe it?

My approach is to try to optimize metabolic flexibility. The way the body works is you put molecules in, chemicals in. Then chemicals respond to it depending on which ones you consumed. In this case the difference between how your body metabolizes fat, protein and glucose it’s pretty dramatic.

You eat a bunch of carbohydrates. In order for your body to get those into the cells to be used as energy, it has to release insulin.

Insulin tells the cells to open up and let glucose out of the bloodstream into the power plant, the mitochondria. The issue there is that insulin, if you are creating a massive blood sugar elevation, you have to release a large amount of insulin to compensate for it.

Over time, there’s this phenomenon called insulin resistance, which sets in, which is essentially, the cells stop responding to the insulin hormone. This is important because it is the underlying factor that determines how you specifically should be setting up your macronutrient balance.

If you’re creating an environment where you’re constantly spiking glucose and constantly spiking insulin without depleting those stores or using them for immediate expenditure, you can create this insulin-resistant environment, which is the beginning of metabolic dysfunction and breakdown.

Over time that’s what I had been doing. I’ve been doing a lot of carb loading. Before every workout or even the night before I would ensure I got in a few 100 grams of complex carbohydrates. I wasn’t eating Pop-Tarts or anything. It was brown rice. It was sweet potatoes. It was making sure that I was fully loaded up.

Even just before my workout I’d have to drive 25 minutes or whatever to the gym. I would have a smoothie. That would be a banana. It would be bran flakes, protein powder. I’d throw some spinach in there to make myself feel good. [laughs]

[laughs] A little bit of fiber and iron in there.

Yeah, [laughs] exactly. It’s green. That would be my pre-workout fuel. I was going to do typically a CrossFit workout. This would be a high intensity WOD. What was fascinating was as soon as I got real time blood sugar data, I saw that that smoothie was causing my blood sugar would go into a diabetic range.

Most people should not exceed 140 after a meal except rarely. Mine would be going well into the 180s and above. That spike would come plummeting back down. I’m sitting in the car. I’m not using that energy. I’m on my way to the gym. It would come plummeting back down within about 45 minutes or an hour.

Just as I’m mid-set, my blood sugar is reaching a reactive hypoglycaemic low. I’m feeling shaky. I’m feeling cold sweat. I’m blaming it on my workout. The reality of the situation was I was causing myself to ride this roller coaster. I was not optimizing my energy.

Seeing that caused me to go to a very different macronutrient balance for my pre-workout which would be almond butter. It would be sometimes I’ll mix in some bran flakes or something high in fiber and make sure I’m getting fats and proteins. I have a much more slow burn.

There’s a product called UCAN which is a slow-release carbohydrate which I’ll often sometimes use. Completely removing the very high fast-acting carbohydrates which I was getting from the banana and those bran flakes and replacing it with something that’s more balanced. In some cases, even removing the meal altogether and going with a fasted exercise.

The rationale for the fasted exercise, what I touched on the beginning, which is training my body to tap into available energy stores that are not necessarily coming from my food, and in this case that would be body fat.

The concept of metabolic flexibility, I’m sure it’s been talked about a lot, but it’s essentially ensuring that your body is hormonally set up to switch between fuel sources effortlessly. A lot of us are basically dependent on a life support drip of food in order to keep running. You take that away for one mealtime, and you’re feeling shaky, you’re feeling like you need to go pass out.

With essentially setting up a training regimen where you are depleting your glycogen reserves and forcing your body to switch over onto your fat reserves, you can start to balance out that hormonal environment and predispose yourself to more easily tap into that energy.

It’s really interesting there. If you look at the raw numbers, most people, average-sized person, has the ability to store about 2,000, 2,500 calories of glucose as glycogen. That same person will typically have, and this is 10 to 15 percent body fat, they’ll have about 80,000 calories of fat stored on their bodies.

There’s plenty of energy there. The concept that we’re going to run out of energy and pass out or die is completely nonsense. It’s training yourself [laughs] to be able to tap into it. That’s what I’m focusing on.

What kind of fasting protocol seems to work for you? Again, I love giving disclaimers. They call me the disclaimer king at BarBend.

This isn’t necessarily ideal for everyone, but for Josh, what might your fasting regimen look like? How do you incorporate that around training?

I really like how you’re showing this through the lens of training, which is something that everyone listening to this podcast or a lot of people, I should say, listening to this podcast are always curious about. They’re like, “Cool, but how does that apply to your training schedule?”

What I’m doing right now is I will typically not eat until around noon to one o’clock. The goal here is, I’ll shut down before about 7:00 or 8:00 PM, I’ll try to be done eating and that will give me a solid greater than 12 hours before I start a workout.

In the morning, if I’m getting up 12 hours after my last meal, my glycogen is pretty well depleted at that point. It’s going to take 18 to 24 hours for most people to be totally cleared out. I’m certainly not fully stocked up. That’s when I’ll do an endurance training session or lightweight kettlebells or something like that.

If I’m going to be pushing really intensely in the gym, I certainly do not need to eat. I’ll get into that. If I’m doing a longer endurance ride, two hours, or a long run, or something like that, I will probably bring along some fuel because the reality of the fact of the matter is, I will balk. I still do not have that amazing metabolic flexibility where I can just seamlessly transition.

I’m still training that, but I’ll be prepared with a little sports drink or something along the way. Now, one of the other guys on our team, it’s pretty amazing, he’s doing marathons completely fasted where he’ll do an 18-hour fast and then he will start a 26-mile run and has been able to do so with perfectly flat blood sugar and with no [indecipherable 21:16] calories.

That’s a demonstration of the fact that this can be trained. Now, going back to the high-intensity stuff. I mentioned how cortisol affects the liver, and it tells your liver to crank out glucose. That kind of cortisol impact happens for me at around 85 to 90 percent of my maximum heart rate.

If I’m sustaining high intensity for more than 5, 10 minutes, I’m going to see a huge blood sugar elevation. That’s my liver kicking in and producing all of this extra energy. That happens regardless of fasted state.

I’ve done 24-hour plus fasts and done a high intensity workout. It certainly doesn’t feel great initially, but once that kicks in, I’ve got all the energy I need. I do not feel like I’m going to crash.

That’s how I’m approaching it. I like to go until noon, one o’clock. My mornings are sacred to me anyway, so not having to do a whole meal preparation and cleanup is great. It unlocks an extra hour of my day.

[laughs] Yeah. I love to get into the personal aspect of this, but right now, just from all I’ve learned about how I function metabolically, I’m biasing towards a high-protein, moderate fat, and low carb lifestyle. I certainly am not ketogenic. I prioritize protein above all else. I tend to be extremely, unfortunately, sensitive to most carbohydrates.

Due to some personal choices around like what I’d like to achieve for longevity and personal health, I’m choosing to bias away from carbs generally.

That makes a lot of sense. This is true for any early stage technology or at least a new framing or a new way in adapting it. You and your team, you’re the guinea pigs in many ways. You’re still in beta, I believe. Is that correct, in Levels?

Yep, that’s right.

The best acolytes, and the best test cases, and the most data, you all can really get it’s from the people working on the product. It’s neat to talk to someone in that stage. You don’t get to do that every day, especially in health and wellness, because many things are rehashes of things that have already been done in health and wellness.

There’s nothing new…We say there’s nothing new in strength training. It was all done in the ’70s and ’80s. People republish it under a different program name.

It’s what we joke about. What are some of the early responses if you’ve had them regarding the product and the impact it can have specifically on strength athletes?

As you touched on it, it’s such a nascent space. It’s brand new. We’re learning a huge amount, literally weekly. One of the things I wanted to quickly loop back on is the personalization component here. Continuous Glucose Monitoring, I touched on this in the beginning.

It’s a very new technology. In the last five years it’s become readily available for people with diabetes. Levels is one of the first to get it to the general population. The interesting thing is, in 2015 a study was published in the “Cell Journal” of Biology, covering this personalized nutrition component.

Essentially, these researchers put 800 people through a one-week experience where there were continuous glucose monitors. They ate standardized foods. They showed that two people can eat the exact same two foods and have equal and opposite blood sugar responses.

In this case, it was a banana and a cookie made with wheat flour. Two people, two these subjects, one would have a huge blood sugar spike from the banana and no response to the cookie. The other person had the opposite responses.

It’s probably something like fruit sugar versus grain sugar, or something along those lines. Then their genealogy, the genetics, their microbiome, their stress environment, body composition, all of these factors come to play to determine how they respond to it.

The point is that they are going to experience an equivalently different hormone response. Their insulin response is going to be different. How they gain weight as a result of that. How energized they’ll feel as a result of that.

That study really flipped the table over on the one-size-fits-all approach. There’s a profound amount of difference between people. A follow-on study actually showed that even identical twins who share 100 percent of their DNA have the same degree of variability available.

It’s not even entirely genetics. That’s the circumstances we’re operating under. What Levels is doing is saying, “We aren’t embracing some dietary philosophy here. What we want is for you, no matter who you are, where you are, what your goals are, to be able to ground your day-to-day choices in objective data coming from your body.

“Rather than you focusing on what the population average does, or what somebody on the Internet says to do, have real data from yourself that you can then use to iterate towards something that works best.” That’s apparent on the team as well.

My co-founder, Casey Means, she’s a vegan plant-based 100 percent. I’m not. Several of us have [laughs] different approaches. We all are striving and using daily this data. Anyway, that’s the foundation that we’re building on.

Given that historically these devices have been used to study diabetic populations exclusively with the exception of those recent studies I touched on, this is an unstudied area. Continuous molecular monitoring for fitness and strength training has not been done yet.

We have some athletes right now, across all professional sports in CrossFit and UFC, in all the pro-leagues, using this as a very early exposure to how their bodies are actually functioning is starting to ground their nutrition training in it.

We were a little too early for conclusions just now. One of the big things people are noticing is what I touched on myself. Which is a lot of the time, the pre-workout and the post-workout that they’re using are not working well for them.

They’re starting to see, “Huh, this whole like shake smoothie thing I’m doing before hitting the gym, I actually feel way better and don’t and based on my blood sugar availability, maybe do not need it at all, and can instead deliver the nutrients for recovery in a much slower-burn fashion.”

Then contrary to that, some people have triple headers where they’re doing back-to-back-to-back performance. They need to have tons of energy available. They’re depleting glycogen all day. They can see basically delivering fuel just in time is made possible by seeing the data happening in the moment.

You’re going to have a lot of Bro scientists really upset…

…if you debunk the strongly-held metabolic window theories.

I’ve seen so many great memes, by the way, slightly off topic about what happens when you violate the 30-minute metabolic window.

I first heard that from a sports’ coach back when I was playing team sports. It’s just something that’s just, it’s so sticky, it stuck around. Get ready for that call…

No doubt. [laughs]

…if they haven’t already.

It’s going to happen. It’s funny because I’m totally open to…What we’re trying to do is, is not just call these things into question but then follow up with what the actual science is. What is optimal? What does it look like to have optimal blood sugar control for a specific set of goals and a certain body composition?

That, I think, we genuinely can crack this. The 30-minute window, for sure, doesn’t apply to everyone, and certainly it depends on how you respond to what you’re consuming. There’s no question in my mind…

Hold me accountable. I’ll die in the cell, but [laughs] there’s definitely more nuance to it than that. I’m looking forward to uncovering exactly how the athlete and then the individual who’s trying to lose 100 pounds, or the person who’s trying to perform better as a new parent. Just trying to keep their wits about them as they’re completely compromised on sleep.

Trying to make their way through life without losing it. You know what I mean? Being able to find an edge, no matter what your performance goals are, is going to become increasingly possible with real-time data in the moment.

Being able to answer the question, “What should I eat, and why?” The why oftentimes is driven by your goals. Answering that with your own objective data is what we’re striving for here.

If you piss off a few Bro scientists along the way, that’s the price of moving the industry forward, right?

No doubt.

I’m sure we’ll be creating a whole new class of Bro scientists with this real-time data too.

We will try and balance the scales. [laughs]

If I were a smarter person, I could come up with a good [indecipherable 30:03] like glucose bros, or something like that. We’ll have to workshop that another time.

[laughs] We’ll workshop that, yeah. [laughs]

Maybe we’ll have you back on the podcast, we’ll spit ball some ideas. Josh, where’s the best place for folks to keep up to date with the work you’re doing and also with what Levels is doing?

We’re building a huge content platform right now with the intention of getting the latest science, not just from within Levels, but the latest metabolic science out into the mainstream. Then we’re also producing our own content on people and their use cases that are currently going through our development project. That’s the blog at levelshealth.com.

On the main website, you’ll also be able to sign up for our waitlist, which is we have an email list and a newsletter and we distribute a lot of details about the product and features, then also new developments in the space.

Whether or not, you’re interested in real-time glucose monitoring when it comes to metabolism, metabolic flexibility, and this new science of real-time data, it’s a good place to start. Then you can follow us on social on Twitter and Instagram, both at Levels.

Excellent. Josh, very much appreciate your time. It’s fascinating to chat with folks in the nascent stages of these developments…

 …because the learnings that you have I’m sure will be groundbreaking in many ways and a bit unpredictable, as we’ve as you’ve already alluded to. Very excited to see how things develop. Thanks so much for joining us.

Thank you, David. It was great.