Uploaded July 2026 | Updated September 2026, 3 weeks ago
The longevity world loves to make health feel complicated. GLP-1s, fasting protocols, testosterone, biomarkers, grip strength, ketones, sleep scores, and wearable data are everywhere, but most people are still missing the bigger question: what actually moves the needle for long-term health?
Dr. Jonathan Schoeff is a surgeon, longevity expert, and co-founder of The Longevity Lab who is still actively practicing medicine. In this episode, he breaks down the real science behind GLP-1s, muscle loss, fasting, testosterone, metabolic health, and the biomarkers that can reveal risks standard labs often miss.
We also talk about why walking after your last meal can change your glucose response, why grip strength is often misunderstood as a longevity metric, how low testosterone can be tied to metabolic dysfunction, and why fasting is only useful when you understand what you are trying to accomplish. He explains how muscle, movement, insulin, sleep, and recovery all connect in a way that makes longevity feel a lot more practical.
If you have ever wondered whether GLP-1s really cause muscle loss, how to fast without wrecking your body, or which health markers are actually worth paying attention to, this conversation will help you cut through the noise and focus on what works.
What’s Discussed:
(1:26:03) Why GLP-1s are more nuanced than the muscle loss headlines suggest.
(1:30:31) How strategic fasting can support fat loss without sacrificing muscle.
(1:33:09) Why fasting activates repair pathways and metabolic flexibility.
(1:39:26) What fasting actually does to insulin, ketosis, and fat burning.
(1:42:29) Why random five-day fasts may not work the way people think.
(1:55:24) How to structure a pre-fast, fast, and post-fast day.
(1:57:02) Why walking after your last meal can change glucose and insulin response.
(2:09:31) How metabolic dysfunction can drive low testosterone in men.
(2:23:29) What biomarkers most doctors miss, including fasting insulin and lipoprotein(a).
(2:31:23) Why grip strength is an overhyped longevity metric and what matters more.
Find more from Jen Cohen:
Website: jennifercohen.com
Instagram: instagram.com/therealjencohen
Books: jennifercohen.com/books
Speaking: jennifercohen.com/speaking-engagements
Find more from Dr. Jonathan Schoeff
Website: longevitylabwellness.com
Instagram: instagram.com/jonschoeff
Facebook: facebook.com/p/Dr-Jonathan-Schoeff-Longevity-Expert-General-Surgeon-61576146488809
YouTube: youtube.com/@drjonschoeff
The longevity world loves to make health feel complicated. GLP-1s, fasting protocols, testosterone, biomarkers, grip strength, ketones, sleep scores, and wearable data are everywhere, but most people are still missing the bigger question: what actually moves the needle for long-term health?
Dr. Jonathan Schoeff is a surgeon, longevity expert, and co-founder of The Longevity Lab who is still actively practicing medicine. In this episode, he breaks down the real science behind GLP-1s, muscle loss, fasting, testosterone, metabolic health, and the biomarkers that can reveal risks standard labs often miss.
We also talk about why walking after your last meal can change your glucose response, why grip strength is often misunderstood as a longevity metric, how low testosterone can be tied to metabolic dysfunction, and why fasting is only useful when you understand what you are trying to accomplish. He explains how muscle, movement, insulin, sleep, and recovery all connect in a way that makes longevity feel a lot more practical.
If you have ever wondered whether GLP-1s really cause muscle loss, how to fast without wrecking your body, or which health markers are actually worth paying attention to, this conversation will help you cut through the noise and focus on what works.
What’s Discussed:
(1:26:03) Why GLP-1s are more nuanced than the muscle loss headlines suggest.
(1:30:31) How strategic fasting can support fat loss without sacrificing muscle.
(1:33:09) Why fasting activates repair pathways and metabolic flexibility.
(1:39:26) What fasting actually does to insulin, ketosis, and fat burning.
(1:42:29) Why random five-day fasts may not work the way people think.
(1:55:24) How to structure a pre-fast, fast, and post-fast day.
(1:57:02) Why walking after your last meal can change glucose and insulin response.
(2:09:31) How metabolic dysfunction can drive low testosterone in men.
(2:23:29) What biomarkers most doctors miss, including fasting insulin and lipoprotein(a).
(2:31:23) Why grip strength is an overhyped longevity metric and what matters more.
Find more from Jen Cohen:
Website: jennifercohen.com
Instagram: instagram.com/therealjencohen
Books: jennifercohen.com/books
Speaking: jennifercohen.com/speaking-engagements
Find more from Dr. Jonathan Schoeff
Website: longevitylabwellness.com
Instagram: instagram.com/jonschoeff
Facebook: facebook.com/p/Dr-Jonathan-Schoeff-Longevity-Expert-General-Surgeon-61576146488809
YouTube: youtube.com/@drjonschoeff
