Protein Helps… But Only If You’re Sending the Right Muscle Signal – Sam Jezak on Senescent Cells, Protein Myths & Longevity (#21)

Samantha Jezak is a biomolecular nutrition researcher completing her PhD at Tufts University, where she studies how diet influences aging at the cellular level. On this episode, we explore the science of longevity through the lens of senescent “zombie” cells, inflammation, and the powerful interaction between nutrition and exercise.

We break down protein hype, keto and carb-loading myths, and why whole foods and micronutrient diversity matter more than extreme diet trends. Samantha also shares her evidence-based perspective on fasting for women, explains the critical role of estrogen in long-term health, and dives into the emerging science of ovarian aging and menopause. Along the way, we discuss how to evaluate nutrition information in a world of social media noise and what the future of “food as medicine” could mean for extending healthspan.

Episode breakdown:

00:00 — Welcome + what Sam studies

00:39 — Senescent cells (hallmark of aging) + nutrition angle

01:55 — Why she chose nutrition + longevity

03:28 — Longevity inputs: genes, exercise, diet, social connection, stress

06:48 — Common misunderstanding: protein hype without training context

09:16 — Keto/low-carb: who it can help + “listen to your body”

11:07 — What a “good diet” means: whole foods + variety

12:36 — Feeling fine vs hidden risk + early markers

14:43 — Nutrient pathways example: niacin → NAD + why restriction can backfire

17:47 — Key micronutrients: vitamin D + magnesium (and creatine)

19:05 — Why supplements aren’t the default: food synergy + absorption

20:33 — Endurance vs strength for longevity

22:39 — High-carb fueling + carb-loading misconceptions

24:23 — Career next steps: postdoc + ovarian aging

26:14 — Fasting for women: autophagy, cortisol, and evidence

30:07 — How to judge nutrition info quality

33:14 — Ovarian aging: follicles, menopause, and the “why” question

35:32 — Estrogen drop: whole-body impacts + HRT reframing

36:59 — Perimenopause: timeline + what women can do now

41:25 — Advice for young scientists

43:12 — The future: AI, robotics, and “food as medicine”

44:39 — Wrap-up

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