The Rich Roll Podcast – Fasting Compilation: Leading Experts On Water-Only Fasts, Fasting Mimicking Diets & The Optimal Fasting Window For Longevity

Date: November 20, 2025
Host: Rich Roll
Featured Experts: Dr. Alan Goldhamer, Dr. Valter Longo, Dr. Satchin Panda, Dr. Michael Greger

Episode Overview

This episode of The Rich Roll Podcast is a comprehensive deep dive into the science, protocols, and personal experiences surrounding fasting for health and longevity. Rich brings together clips and insights from leading experts—Dr. Alan Goldhamer, Dr. Valter Longo, Dr. Satchin Panda, and Dr. Michael Greger—to discuss the nuances between water-only fasting, intermittent fasting, time-restricted eating, and the fasting mimicking diet (FMD). Their perspectives illuminate the therapeutic potential, risks, myths, and optimal strategies for adopting fasting in the pursuit of health, disease reversal, and extended vitality.

Key Discussion Points & Insights

1. Defining the Many Faces of Fasting

• Fasting types: Intermittent fasting, time-restricted eating, alternate day fasting, 5:2 fasting, fasting mimicking diet, water-only fasting ([00:46]).
• Dr. Alan Goldhamer's focus: Medically-supervised, therapeutic, water-only fasting versus other fasting protocols, emphasizing safety and efficacy for chronic disease ([04:32]).

2. Water-Only Fasting: The Goldhamer Protocol

• Nature of protocol: "Complete abstinence of all substances except water in an environment of complete rest." ([04:32])
• Therapeutic intent: "It's not something that… you'd necessarily look forward to if you're ill. But the fact is, it can be done safely, it can be done effectively, and when it's needed, there’s nothing else that does exactly what water only fasting does." – Dr. Alan Goldhamer ([06:51])
• Length & supervision: Fast lengths range from 5 to 40 days, followed by supervised recovery (half the fast duration for refeeding), careful medical evaluation and monitoring ([07:22]).

Clinical Use Cases:

• Resistant hypertension, type 2 diabetes, certain autoimmune diseases, and select cancers (notably lymphoma) ([07:22]).
• Individualized approach based on patient’s medical history, lab work, visceral fat stores, organ function, and electrolyte status ([08:48]).

Outcomes & Mechanisms:

• Preference in body to lose visceral fat (“much like tumors are”), leading to improvements in inflammation and disease ([11:02]).
• DEXA scans show disproportionate mobilization of visceral vs. subcutaneous fat (e.g., 20% total fat loss, 55% visceral fat loss after two-week fast in men) ([11:45]).
• Rapid sodium excretion and “detoxification” via fat loss ([43:11]).

3. Time-Restricted Eating: The Panda-Longo Consensus

• Optimal window: Both suggest 11–12 hours of feeding and 12–13 hours of fasting per day ([00:02], [13:34]).
  • “No physician will ever argue that that's a bad idea. And really not a single paper saying that this is not safe or that is not effective or at least partially effective…” – Dr. Satchin Panda ([15:09])
  • “12 hours is a much safer way to go… not as effective, of course, as 16 hours… but still effective.” – Dr. Valter Longo ([13:32])

Practicality:

• Realistic for most given that average modern eating window is 15+ hours. Reducing to 12 hours offers meaningful metabolic benefit ([18:15]).
• Improved sleep with reduced eating windows, especially avoiding food 3 hours before bedtime ([19:50], [20:47]).
• Flexibility: If late eating doesn’t disturb sleep, may not be harmful, but listen to feedback from the body ([20:47]).

4. Fasting Mimicking Diet (FMD): The Longo Approach

• What is FMD?: Plant-based, low-calorie, low protein, low sugar, high plant-based fats. Caloric intake carefully modulated to simulate fasting without total deprivation ([17:32], [59:04]).
• Clinical protocols: Typically 4–7 days. Effective cycles are 2–4 times a year for disease prevention and management, with tailored protocols for cancer, autoimmune diseases, and Alzheimer’s ([58:05]).
  • "So now we have 30 clinical trials running... that's the way you should allow everybody to test it." – Dr. Valter Longo ([57:43])

Advantages:

• Safer and feasible for at-home use, better compliance than true fasting.
• Shown to induce insulin sensitivity and maintain lower IGF-1 (“pro-aging” growth factor) for months post-cycle ([47:33]).
• Long-term commitment: Must be undertaken as part of an overall lifestyle and with close support from medical and nutrition teams for complex cases ([59:03]).

5. Intermittent Fasting & Early vs. Late Eating

• Mixed evidence: “Some studies show it's great for you, other studies show it's terrible for you, it has all these negative metabolic consequences.” – Dr. Michael Greger ([00:14])
• Key factor: Timing matters. Early time-restricted feeding (breakfast-centered, skipping supper) is beneficial; late feeding (skipping breakfast, eating at night) can be harmful ([29:18]).
  • “If you miss any meal, it should be supper, not breakfast.” – Dr. Michael Greger ([29:57])
  • Population data: Seventh-Day Adventists in Loma Linda (longest-living group) often skip dinner, not breakfast ([30:06]).

No More Superficial Diet Debates:

• “[Fad diets are] like whack-a-mole... Let’s just [create] criteria against which you can look at any future diet.” – Dr. Michael Greger ([24:15])

6. Safety, Suitability, and Cautions

• Strict Supervision Required for Water-only Fasts: Not suitable for those on irreplaceable medications, with cardiac history, on anticoagulants, or with conditions where weight-loss is perilous (e.g., anorexia, some chemotherapy patients) ([66:03]).
• Medication Management: “Most people are being treated—medicated—for their diet. When you change their diet, the need for medication dramatically [drops]…” – Dr. Alan Goldhamer ([37:07])
• Self-selection: Goldhamer works mainly with highly motivated individuals, emphasizing that long-term maintenance of benefits depends on lifestyle adherence ([72:40]).

Notable Quotes & Timestamps

• On why long water-only fasting?

  • “Many conditions won’t respond [to intermittent fasting]. That’s oftentimes when we see people... when they’ve done their best… but the blood pressure still persists.” – Dr. Alan Goldhamer ([06:06])

• On visceral fat loss:

  • “For example, we used a DEXA scanner... typical male fast for two weeks loses 20% of their total fat, but 55% of their visceral fat. So the visceral fat is being mobilized much like tumors are.” – Dr. Alan Goldhamer ([11:45])

• On the 12-hour fasting window:

  • “No physician will ever argue that that's a bad idea. And really not a single paper saying that this is not safe or that is not effective...” – Dr. Satchin Panda ([15:09])

• On late-night eating and sleep:

  • “If you eat late and that’s a big deal to someone but that doesn’t really affect you negatively, I don’t think there’s too much data suggesting you’re going to live 10 years shorter because of that. So if you’re sleeping well, that’s probably okay, an okay compromise.” – Dr. Satchin Panda ([20:49])

• On the fasting mimicking diet’s design:

  • “Nutrient technology... making it easier for you to lose weight rather than starving you for a year hoping that you stay like that for the rest of your life, which you're never going to do.” – Dr. Valter Longo ([52:32])

• On skipping breakfast vs. supper:

  • “If you miss any meal, it should be, it should be supper, not breakfast.” – Dr. Michael Greger ([29:57])

• On why population-level change is slow:

  • “To me, if I look at humanity as a whole, it would be very stressful and I don’t like stress. So what I do is instead I look at the fact that I’m going to do everything I can do to influence the one or one and a half or 2% of the population that are hungry for information...” – Dr. Alan Goldhamer ([72:40])

• On core prescription for health:

  • “Health results from healthful living. So if you want to be healthy, you gotta pay the price and live healthily... whole plant food SOS free diet, exercise within your capacity, abundant sleep… Fast every day for 12 to 16 hours. Fast occasionally as appropriate…” – Dr. Alan Goldhamer ([73:47])

Memorable Moments & Recommendations

• Personalized Practice:
  • Dr. Alan Goldhamer shares he fasts 16 hours daily, plus a one-week fast annually. “I don't like fasting. You have to rest when you fast. You can't play basketball. It's really annoying.” ([70:07])
• Meal timing and metabolic health:
  • Dr. Michael Greger highlights research—same calories eaten at breakfast vs. supper, breakfast group loses weight, supper group gains ([23:51]).
• On practicality:
  • Dr. Longo stresses the importance of realistic protocols for broad adherence; most people won't do 2-day fasts per week, but FMD a few times a year is manageable ([53:13]).
• Systemic critique:
  • “It’s really criminal, I think, in the United States, in Europe, all over the world. I call it unconspired conspiracy... a lot of bad food and a lot of drugs... The average 45-year-old now has got two chronic conditions in the United States.” – Dr. Valter Longo ([59:04])

Key Segments & Timestamps

• Defining fasting methods: [00:46]
• Water-only fasting and selection: [04:32]–[08:48]
• Visceral fat and disease: [09:48]–[12:44]
• Time-restricted eating science: [13:12]–[15:48]
• Practicality of fasting windows: [18:15]–[19:50]
• Fasting mimicking diet mechanisms: [17:12], [53:13]–[59:04]
• Intermittent fasting research & meal timing: [22:44]–[30:44]
• Medication, safety, and fasting: [36:44]–[38:33], [66:03]–[68:58]
• Personal fasting practices: [69:01]–[70:56]
• Why radical interventions are needed: [71:16]–[72:40]
• Final recommendations: [73:47]

Conclusion

The Rich Roll Fasting Compilation delivers a sweeping, evidence-rich exploration of fasting’s potential for personal wellbeing and societal change. The experts underscore that fasting—when matched to individual need, safely supervised, and accompanied by a healthy diet and lifestyle—offers outsized benefits for disease reversal and longevity. The consensus recommends daily 12-hour fasting windows as safe and effective for most, with longer, supervised fasts or FMD cycles reserved for specific cases. Always, the path starts with motivation, support, medical input, and a commitment to lasting lifestyle change.

For full episodes and further details, access the episode page at richroll.com.