Podcast Summary:

BETTER! Muscle, Mobility, Metabolism & (Peri)Menopause with Dr. Stephanie

Episode: Confused or Against Fasting? A New Perspective for Women with Dr. Chris Rhodes

Date: December 1, 2025
Host: Dr. Stephanie Estima
Guest: Dr. Chris Rhodes, Nutritional Biochemist

Episode Overview

This episode explores the benefits and challenges of fasting for women—particularly those in perimenopause and menopause—through an expert conversation between Dr. Stephanie Estima and Dr. Chris Rhodes. Dr. Rhodes, whose research focuses on the molecular effects of prolonged fasting (especially 36-hour fasts), unpacks why fasting has such significant impact on health, lifespan, and metabolism, but also why “classic” fasting protocols may not suit every (peri)menopausal woman. The discussion covers the molecular signatures of fasting, hormonal considerations, and how fasting “mimetic” compounds (notably those in the supplement Mimeo) may replicate fasting’s benefits—potentially without the downsides of long fasting periods for women. The episode melds deep science with actionable strategies, seeking to empower listeners to find individualized, sustainable paths to healthy aging.

Key Discussion Points & Insights

1. The Biology and Rationale of Fasting

[06:01] Dr. Chris Rhodes

• Fasting is unique in its ability to reliably extend lifespan across animal models, prevent or delay major diseases, and activate a “longevity bio program”—not by adding nutrients, but by triggering endogenous repair mechanisms.
• Key Mechanisms Activated:
  • Glucose → fat/ketone metabolism switch
  • Activation of autophagy: cellular cleanup and recycling
  • Upregulation of NAD, sirtuins, AMPK, PPARs, NRF2 (related to stress defense, DNA repair, and longevity)
  • Downregulation of mTOR (reducing pro-growth signals)

“Fasting seems to have all of these really, really amazing impacts... somehow fasting is turning on this what I call longevity bio program that we all kind of have inside of us.” – Dr. Chris Rhodes [06:24]

2. Types and Duration of Fasts—What Is "Enough"?

[12:24] Dr. Rhodes

• 16:8 fasting (16 hours fasting, 8-hour eating window) is popular, but does not achieve a full metabolic switch or most cellular/anti-inflammatory benefits.
• True fasting state (20–24+ hours): Needed to deplete glycogen, shift to repair mode, stimulate autophagy, ketone production, and key anti-inflammatory molecules.
• 36-hour fasts / Alternate day fasting: Best studied for lifespan extension, significant anti-inflammatory, metabolic, and cellular resilience effects—even without reducing overall weekly calories.
• Multi-day fasts (72+ hours): Lead to deeper autophagy, stem cell/immune cell regeneration, and may play roles in cancer prevention.

“To really get even into the early stages of, you know, this metabolic switch, these biochemical fasting processes, you really have to fast for much longer than people think that they do.” – Dr. Rhodes [12:24]

3. Molecular and Cellular Changes During Fasting

[18:50] Dr. Rhodes

• 36-hour fasts result in:
  • Sharp drop in glucose, rise in ketones (energy switch)
  • Elevation of 300+ unique plasma metabolites
  • Increases in NAD+ (key for DNA repair/sirtuin activation)
  • Upregulation of anti-inflammatory and autophagy-related metabolites (e.g., spermidine)
  • Measurable improvements in cellular antioxidant capacity, anti-inflammatory effects, cardioprotection, and stress resilience in both men and women

"There were these universal effects, basically taking already young healthy people and turning them into super people, which was really, really fascinating." – Dr. Rhodes [21:19]

4. Fasting and Hormones—Particularly for Women in (Peri)Menopause

[27:47] Dr. Estima & Dr. Rhodes

• Key concern: As estrogen declines, so does the body’s ability to maintain NAD+ levels, possibly blunting fasting’s longevity benefits for menopausal women.
• Research suggests postmenopausal women have similar molecular fasting responses as men, but perimenopausal women’s hormonal fluctuations can make them more sensitive (i.e., vulnerable to disrupted sleep, higher cortisol, thyroid suppression).
• Fasting elevates cortisol (the body's stress hormone), which can:
  • Disrupt sleep, increase belly fat, worsen mood in women, especially in perimenopause
  • Enhance HPA (stress axis) sensitivity

“Women tend to show a greater HPA axis sensitivity...in the absence of calories...especially true for women in perimenopause.” – Dr. Estima [30:23]

• Fasting can also reduce thyroid hormone T3, compounding fatigue and slowing metabolism, particularly concerning for women already at risk for thyroid disorders (e.g., Hashimoto’s).
• Women may need to be more cautious with prolonged fasts—balancing potential gains against hormonal stress.

5. Muscle & Bone Preservation During Fasting

[40:49] Dr. Rhodes

• Muscle:
  • After glycogen stores are depleted, body begins gluconeogenesis (making glucose from protein) first drawing from liver/kidney proteins, then from muscle if fasting continues.
  • "Use it or lose it": Resistance training signals your body to maintain muscle, even during fasting; endurance cardio may increase muscle catabolism.

“Your body won't start catabolizing your muscle if it thinks that it's necessary to your survival. So if you are doing strength training when you're doing the fast, that's going to be sending a signal...that, hey, we actually need these to, you know, stay alive...” – Dr. Rhodes [43:13]

• Bone:
  • Blood acidifies during fasting due to ketone buildup; body buffers this by pulling calcium from bones, increasing risk for bone loss.
  • Weight-bearing/impact exercise stimulates bone-building even during a fast.

6. Fasting "Mimetics": Replacing the Fast?

[47:49 & 59:34] Dr. Rhodes

• Dr. Rhodes’ research found four key metabolites highly elevated during fasting: PEA, OEA, spermidine, and nicotinamide, which together replicate much of fasting’s molecular/multisystem benefit.
  • PEA (Palmitoylethanolamide): Anti-inflammatory, pain-relief, mood, nerve health
  • OEA (Oleoylethanolamide): Appetite suppression, triggers fat burning, metabolic switch
  • Spermidine: Promotes autophagy (cell cleaning/renewal), correlated with longevity, neuroprotection
  • Nicotinamide: NAD+ precursor, activates sirtuins/DNA repair
• These are combined in the supplement Mimeo.
  • Clinical pilot: 8 weeks of daily Mimeo reduced biological (epigenetic) age by 2.5 years; significant improvements in metabolic markers (glucose, cholesterol, testosterone).
  • Double-blind study in 50+ adults: Marked improvements in hunger, cravings, satiety, similar benefits seen for both men and women.
  • No evidence of significant muscle/bone loss or negative impact on thyroid identified in their trials (to date).

"The whole point of mimeo and this whole formulation is so that you can get the benefits of fasting without having to fast." – Dr. Rhodes [59:34]

7. Practical Application & Protocols

[68:41] Dr. Rhodes

• Mimeo is designed for daily use—either to mimic the metabolic/hormonal effects of a 36-hour fast, or to make fasting intervals easier/more effective for those who do fast.

  • Dosages in Mimeo: 600 mg PEA (ultra-micronized), 400 mg OEA, 8 mg spermidine, 250 mg nicotinamide.

• Benefits for midlife women:

  • Appetite and cravings control ("menopause munchies")
  • Metabolic stabilization during perimenopausal hormone declines
  • Potential anti-inflammatory and pain-modulating effects (e.g., for joint discomfort, fibromyalgia, menstrual pain)
  • Ease of supplementation vs. prolonged restrictive fasting

8. Limitations, Research Gaps, and Moving Forward

[70:17 & 74:31] Dr. Estima & Dr. Rhodes

• There’s a notable lack of high-quality long-duration studies on fasting and fasting mimetics in women, especially in perimenopause/menopause.
• Future needs: Large, long-term studies; exploration of other fasting/eustress metabolites; trials on muscle, bone, pain, and different hormonally sensitive populations.

“We need more research, certainly with fasting and just generally women's health…what is the impact on women?” – Dr. Estima [77:50]

Notable Quotes & Timestamps

• Why Fasting?

  “Fasting is turning on this what I call longevity bio program that we all kind of have inside of us.”
  – Dr. Rhodes, [06:24]

• 16:8 Not Enough

  “From a biochemical perspective, a 16 hour fast is actually not long enough to really get you into a biological state of fasting.”
  – Dr. Rhodes, [12:24]

• Synergy of Fasting Metabolites

  “When we combine them all together...we got this 96% lifespan extension. So there’s really this synergistic effect activating these complementary pathways...”
  – Dr. Rhodes, [49:45]

• On Women’s Sensitivity to Fasting Stress

  “Aggressive fasting ...for women in midlife who are trying to preserve muscle and bone... seems to have for women come at such a high cost.”
  – Dr. Estima, [70:17]

• Why Fasting Mimetic Compounds?

  “If we can use science to tease out…what are the beneficial things versus what are the negative things, and then just like take all the beneficial things. That’s just a wonderful feat of human biohacking.”
  – Dr. Rhodes, [73:03]

Timestamps for Key Segments

| Segment | Start | |---------------------------------------------------------|-----------| | Why fasting is uniquely powerful | 06:01 | | What duration is "biologically meaningful"? | 12:24 | | What happens in the blood at 36+ hours? | 18:50 | | NAD, estrogen, aging & the female difference | 25:41 | | Fasting, Cortisol, Thyroid: Hidden stressors for women | 30:23 | | Preserving muscle/bone during fasts | 40:49 | | Is it safe for thyroid/hormones? | 34:09 | | Fasting “mimetic” molecules (Mimeo) explained | 47:49 | | Clinical results for Mimeo and practical use | 59:34 | | How/when to use fasting mimetics vs. fasting | 68:41 | | Future research directions & summary | 74:12 | | Dr. Stephanie’s after-party wrap-up | 77:50 |

Actionable Takeaways

• If you’re a midlife woman or dislike prolonged fasts but want inflammation, longevity, and metabolic benefits, focus on:

  • Resistance training to preserve muscle/bone
  • Considering a fasting mimetic supplement protocol like Mimeo as a daily baseline for cell renewal, satiety, and pain modulation—especially if full fasts are impractical or impact hormonal health
  • Prioritizing real food, adequate protein, and overall calorie awareness
  • Monitoring response: Adjust based on mood, sleep, energy, cycles

• Be mindful: Fasting research on women’s long-term hormonal, thyroid, or bone impacts is still limited; personalized moderation and medical consultation are key.

For More from the Episode

• Dr. Chris Rhodes:
  • TikTok: @thatnutritiondoctor
• Mimeo Fasting Mimetic Supplement:
  • mimeohealth.com
  • IG: @mimeohealth

In sum:
This episode offers a nuanced, science-backed look at how women in midlife can harness fasting’s benefits—without sacrificing muscle, bone, or quality of life—and paves the way for a new “biohacking” approach that leverages molecular fasting mimetics for safer, more accessible wellness.