Most people think longevity is about living longer.

Dr. Jack Kreindler thinks that's exactly where we've gone wrong.

The longevity industry has never been bigger. Every week there's a new supplement, a new biomarker, a new biohack, or a new promise that you can slow aging.

But after more than 25 years working with elite athletes, founders, CEOs and patients facing life-threatening disease, Jack has reached a very different conclusion.

The goal isn't to live longer. It's to stay fully alive for as long as possible.

In this episode of Return on Health, hosts Niko Hems and Miguel Medina sit down with one of the world's leading physicians in preventive medicine and human performance to separate evidence from hype.

We explore why Jack has become one of the biggest critics of the word longevity, what he really thinks about Bryan Johnson and David Sinclair, whether NAD boosters actually make sense, and why purpose, relationships and resilience may be more powerful than the latest biohack.

━━━━━👤 ABOUT THE GUEST━━━━━

Dr. Jack Kreindler is a physician, physiologist and entrepreneur specializing in preventive medicine, human performance and healthy aging.

He is the Founder & CEO of WellFounded and previously founded the Centre for Health and Human Performance (CHHP) in London, where he pioneered a model combining elite sports science with clinical medicine.

Over the past two decades, he's worked with Olympic athletes, military personnel, founders, CEOs and patients with complex medical conditions - helping them maximize health, performance and resilience rather than simply adding years to life.

━━━━━🎙️ ABOUT THE HOSTS━━━━━━

Niko Hems

Niko Hems is a longevity expert and Head of Growth at YEARS, a company building a longitudinal, multi-modal health dataset to make prevention personal and data-driven.

Miguel Medina

Miguel Medina is co-host of Return on Health, a podcast built on a simple idea: a system always produces the outcomes it's incentivized to produce - so if we want better health outcomes, we need better incentives.

━━━━━━CHAPTERS━━━━━━

00:00 Why Jack Rejects the Word "Longevity"

01:33 What People Are Really Asking For

03:29 Healthspan vs. Lifespan

08:42 The Pillars That Actually Matter

12:02 What Happens Inside a Longevity Clinic

17:56 The Biomarkers Worth Paying Attention To

19:45 Why Human Connection Might Be the Ultimate Biomarker

28:25 Environmental Toxins & Modern Living

32:50 Are Toxins Really Making Us Sick?

36:14 Bryan Johnson, David Sinclair & Longevity Escape Velocity

40:03 What Founders Can Learn From Elite Performers

44:06 Burnout, Stress & High Performance

47:27 Can We Really Make 90 the New 60?

48:30 The Longevity Supplement Jack Would Never Take

49:40 The Supplements He Actually Recommends

51:15 Will AI Replace Doctors?

52:51 The Biggest Problem With Modern Healthcare

━━━━━💡 KEY QUESTIONS ANSWERED━━━

• Is the longevity industry focusing on the wrong goal?

• Can you actually extend your lifespan - or just your healthspan?• Are expensive longevity supplements worth the money?

• What does Jack really think about Bryan Johnson's Blueprint?

• Which supplements have the strongest evidence today?

• Why is VO₂ Max one of the most powerful predictors of long-term health?

• Are environmental toxins a bigger problem than we realize?

• Can AI become a better doctor than humans?

• Why might relationships, purpose and meaning outperform the latest biohacks?

• What would Jack change about modern healthcare if he could?

Connect with Jack

🌐 WellFoundedhttps://wellfounded.health

🏥 Centre for Health and Human Performance (CHHP)https://chhp.com

💼 LinkedInhttps://www.linkedin.com/in/jackkreindler/

Is the longevity supplement hype real - or are you wasting money? Bestselling author Bas Kast breaks down what actually works in nutrition, supplements, and slow aging.

Most people don't suffer from a lack of health advice. They suffer from too much of it. One expert says eat more protein, the next says cut animal foods. One says supplements are useless, the next sells a 100-pill longevity stack - and all of it sounds convincing.

In this episode of Return on Health, hosts Niko Hems and Miguel Medina sit down with Bas Kast - the science author whose book The Diet Compass (Der Ernährungskompass) sold over 1 million copies - to separate evidence from noise. We cover what still holds up in nutrition science, which supplements are worth taking (and which are pure marketing), why you are never the "average" person in a study, and Bas's new project SlowAger.

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👤 ABOUT THE GUEST

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Bas Kast is a science journalist and bestselling author known for translating complex nutrition and longevity research for a general audience - without academic jargon or wellness hype. His book "The Diet Compass" (Der Ernährungskompass) became an international bestseller with 1M+ copies sold, grounded in thousands of peer-reviewed studies. His newer work focuses on vitamins and supplements (the "Vitamin Compass" / Der Vitamin-Kompass), and his current project, SlowAger, explores the messy intersection of nutrients, supplements and healthy aging.

━━━━━━━━━━━━━━━

🎙️ ABOUT THE HOSTS

━━━━━━━━━━━━━━━

Niko Hems is a longevity expert and Head of Growth at YEARS, a company building a longitudinal, multi-modal health dataset to make prevention personal and data-driven.

Miguel Medina is co-host of Return on Health, a podcast built on a simple idea: a system always produces the outcomes it's incentivized to produce - so if we want better health outcomes, we need better incentives.

━━━━━━━━━━━━━━━

⏱️ CHAPTERS

━━━━━━━━━━━━━━━

00:00 Too much health advice — the real problem with health information

01:18 How Bas Kast got into nutrition: headaches, low-carb & a personal wake-up call

05:15 Where health communication goes wrong: incentives & the Brian Johnson effect

12:19 The 3 principles of healthy eating (Michael Pollan's rule explained)

15:04 What Bas changed his mind on: whole grains, the gluten myth, cheese & intermittent fasting

21:01 Population data vs. personalization: why nutrition averages mislead you

28:28 A data-driven future for nutrition, CGMs & the 10-year Diet Compass update

33:25 The supplement hype: do we really need supplements? (NMN, NR, spermidine, taurine)

44:48 SlowAger, low-dose lithium & how to weigh risk vs. caution

51:06 Lightning round: 3 steps to use supplements intelligently

52:39 The most underrated supplement category (AREDS, lutein & zeaxanthin for eye health)

57:20 Return on Health: the one thing to fix in medicine — treat your body like your teeth

━━━━━━━━━━━━━━━

💡 KEY QUESTIONS ANSWERED

━━━━━━━━━━━━━━━

- Do longevity supplements like NMN, NR and spermidine actually work?

- What are the 3 simple rules for a healthy diet?

- Is gluten bad for you if you're not sensitive?

- Why does the same diet work for one person and fail for another?

- Which supplements are actually backed by strong evidence?

- Is low-dose lithium safe as a supplement?

- Why is the medical system "too reactive" — and how do we fix it?

━━━━━━━━━━━━━━━

🔗 LINKS

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📚 Bas Kast - The Vitamin Compass: https://vitaminkompass.com/

🔔 Subscribe for a new episode every week

Functional Medicine MD: What 5,000+ Patients Taught Him About Root Cause Medicine

In this episode of Return on Health, we speak with Dr. Peter Martin, physician, former CNS pharmacology researcher, and founder of FunMed, one of Europe’s leading functional medicine clinics.

Peter spent around 15 years in pharmacology research before his own burnout pushed him to look beyond the conventional model of symptom control. What started as a personal search for recovery became a data-driven clinical model built around root cause medicine, extensive biomarker testing, gut health, metabolism, and chronic disease prevention.

We talk about what functional medicine actually means, why chronic disease often needs a different care model, and what Peter has learned from treating more than 5,000 patients. He explains why fasting insulin may be one of the most overlooked markers in modern healthcare, how low-grade inflammation is often connected to gut health, and why normal lab results do not always mean someone is truly healthy.

We also get into the controversial parts: large biomarker panels, false positives, red meat, vegan diets, anti-nutrients, carnivore diets, and the weakness of much nutrition research. Peter also shares why he believes functional medicine could become part of the European healthcare system, especially if reimbursement shifts from visits and procedures toward actual health outcomes.

This episode covers:

• What 5,000+ patients taught him

• Why fasting insulin is often missed

• How root cause medicine could change care

Topics discussed:

00:00 Introduction
01:00 What FunMed does differently
02:00 Real-world data from 5,000+ patients
03:30 From CNS pharmacology to functional medicine
07:00 Root cause medicine vs symptom control
10:30 Precision health in Sweden and Germany
15:30 Why FunMed tests around 200 biomarkers
21:00 False positives and the problem with large panels
28:00 Fasting insulin and insulin resistance
31:00 Low-grade inflammation and gut health
35:30 Low-carb and ancestral nutrition
41:00 Vegan diets, nutrient deficiencies, and bio-individuality
49:30 Red meat, nutrition research, and epidemiology
56:00 Functional medicine and insurance coverage
59:00 Rapid fire: biomarkers, magnesium, carnivore diet, healthcare reform

Guest

Dr. Peter Martin

Physician, former CNS pharmacology researcher, founder of FunMed, and one of the leading voices trying to bring functional medicine and precision health into European healthcare.

Guest links

LinkedIn: https://www.linkedin.com/in/peter-martin-31b23342/
FunMed: https://www.funmed.se/?srsltid=AfmBOorlgUNnEK1ba7p_zIxug35sx3YMSq6PmYiufq6xJH1VAQ-EiQc0

Return on Health is available wherever you get your podcasts.

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