Reading time: 5 minutes
What I Discuss with Josh Clemente:
- How his love of coffee began at SpaceX, evolved into a daily espresso ritual, and why caffeine can cause sharp, individual blood sugar and insulin spikes…04:17
- How genetics affect caffeine metabolism, why coffee can briefly raise blood sugar but still support long-term health, and why coffee itself, even decaf, matters more than caffeine alone…08:49
- Why continuous glucose monitoring (CGM) blood sugar spikes during healthy activities like exercise, sauna, or coffee aren’t something to panic about, and how having more properly framed health data can actually reduce anxiety and lead to better long-term decisions…11:50
- The impact of alcohol and how it lowers blood sugar by hijacking normal metabolism, masking glucose spikes while quietly increasing fat storage and metabolic risk…24:45
- Surprising CGM data showing that red light exposure at specific wavelengths can significantly lower blood sugar, opening a fascinating, still-unexplained frontier in metabolic health…33:51
- How CGM data shows that simply tracking glucose can drive weight loss, why low-carb diets don’t affect everyone the same way, and how ketones can help some people function well at lower glucose levels…39:57
- How eating too close to bedtime, especially a high-carb meal, can worsen sleep and raise next-day blood sugar…47:01
- How inflammation and changing hormones across the menstrual cycle create major shifts in blood sugar patterns, from the follicular and luteal phases through menopause…50:59
- How modern wearables and health apps can sync together to improve cycle tracking and glucose insight, and why newer CGMs like Stelo offer a smoother, more practical experience for everyday users…57:28
In this fascinating episode with repeat guest, Josh Clemente, founder and CEO of Levels, you’ll discover what your blood sugar is really doing all day long—and why that matters far beyond diabetes. If you’ve ever wondered about the patch on my arm, been curious about continuous glucose monitors (CGMs), or wanted to understand how everyday habits affect your health at a cellular level, this conversation is for you. Together, we unpack how CGMs are changing the way people think about metabolism, energy, and long-term health.
We kick things off with a surprisingly relatable entry point: coffee. You’ll hear how Josh’s relationship with coffee began during his SpaceX days and how that curiosity eventually led to exploring some fascinating data about caffeine, antioxidants, and blood glucose. Using Levels’ massive real-world dataset, we explore why some people experience huge glucose spikes from coffee while others see almost no response (and how genetics, timing, and context all play a role).
If you think CGMs are only for people with diabetes, this episode will challenge that assumption. You’ll learn how CGMs became accessible to everyday health seekers, what the data reveals about alcohol (spoiler: it often crashes glucose rather than spiking it), and how certain habits can mask metabolic stress even when things look “fine” on the surface. This is the kind of insight you won’t find in standard medical advice, but it can dramatically change how you eat, train, sleep, and recover.
By the end of this conversation, you’ll walk away with a clearer understanding of how to use tools like Levels, Dexcom, or Stelo—along with wearable data—to reveal what’s actually happening under your skin. Whether you want to optimize performance, feel more stable throughout the day, or simply make smarter choices about food and caffeine, this episode gives you practical, data-driven clarity on metabolic health in the real world.
Josh Clemente is a systems engineer and metabolic health enthusiast. At SpaceX, he led a team to develop life support systems that, in May of 2020, began sustaining astronauts on trips to and from the International Space Station aboard Crew Dragon: the first privately developed human-rated orbital spacecraft in history. Josh has spent the past decade obsessed with extending the lives of those he loves by breaking down barriers to better, more accurate, and more frequent measurement of human health. He enjoys the outdoors, functional fitness training, technology, coffee, and restoring motorcycles.
Fun fact: Josh was homeschooled K–12, along with his eight siblings, by his legendary mom.
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Please Scroll Down for the Sponsors, Resources, and Transcript
Episode Sponsors:
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Boundless Bar: If you’re ready to fuel workouts, sharpen your focus, and support whole-body vitality, grab your Boundless Bars now at boundlessbar.com —and save 10% when you sign up for a Boundless Bar subscription.
Resources:
- Guest Name:
- Studies:
- Caffeine ingestion elevates plasma insulin response in humans during an oral glucose tolerance test
- Coffee & Long-Term Diabetes Risk Studies
- Red Light Therapy Study – Light stimulation of mitochondria reduces blood glucose levels
- Metabolic Effects of Late Dinner in Healthy Volunteers—A Randomized Crossover Clinical Trial
- Impact of insufficient sleep on dysregulated blood glucose control under standardized meal conditions
- How does menopause impact weight and metabolic health?
- Levels’ 3-Year, 75,000-Participant CGM Study — Levels conducted a multi-year IRB-approved study with 75,000 participants to map real-world glucose patterns in non-diabetic individuals.
- Articles
- Podcasts
- A Rocket Scientist Homeschooler’s Insider Blood Glucose Monitoring Secrets, The Best Way To Use A Continuous Glucose Monitor (CGM), Blood Sugar Biohacking Tips & Much More!
- Everything You’ve Ever Wanted to Know About Blood Sugar & Glucose Monitoring, But Were Afraid To Ask Or Didn’t Realize, With Casey Means Of Levels.
- Keto vs. Carnivore, Hormonal Chaos from High Protein, the *Surprising* Truth About Cold Exposure, and Why Carbs Are CRUCIAL with Jay Feldman
- Supplements/Nutritional Compounds
- Devices
- Levels app (CGM tracking and integration)
- Whoop
- Oura Ring
- Red light therapy device (full-body red light bed)
- Tests
Upcoming Events:
CREATE 26 — January 28–30, 2026
Join me in Tucker, Georgia, at CREATE 26, a high-level gathering of founders, creators, and leaders focused on building scalable businesses, powerful networks, and aligned lives. This immersive multi-day experience blends strategy, leadership, and personal optimization with real-world execution and high-impact connections. You’ll also have the opportunity to join me for select sessions and a special Health Panel Q&A on Thursday, January 29. If you’re serious about growth in both business and life, this is a room you want to be in. Grab your ticket here.
Keep up on my LIVE appearances by following bengreenfieldlife.com/calendar!
Do you have questions, thoughts, or feedback for Josh or me? Leave your comments below, and one of us will reply!