Podcast Summary

Podcast: The Dr. Gundry Podcast
Episode: Feeling Hangry While Fasting? Here’s Why (and how to make fasts easier) | EP 381
Date: December 9, 2025
Host: Dr. Steven Gundry
Theme: A science-backed, practical guide to intermittent fasting—why it can feel miserable for many, what happens inside your body during a fast, foods and drinks that won’t break your fast, and gentle strategies to make fasting easier and more effective for real people.

Episode Overview

Dr. Steven Gundry dives deep into the science of intermittent fasting, breaking down why so many people feel “hangry” or struggle when they attempt fasting protocols. He emphasizes the importance of metabolic flexibility, common pitfalls, myths about what breaks a fast, and practical, evidence-backed strategies to make fasting easier and more sustainable. The discussion is backed with research, clinical experience, and clear “do’s and don’ts” for listeners at any stage of their fasting journey.

Key Discussion Points & Insights

1. What Happens in Your Body During Fasting? (02:06 - 07:08)

• Metabolic Flexibility is Key:
  Dr. Gundry highlights that most people—regardless of weight—lack the ability to easily switch between burning sugar and burning fat for fuel.
  • “The vast majority of people…have such high insulin levels…are so metabolically inflexible that they absolutely do not do well with intermittent fasting. Shocking but true.” (02:06, Dr. Gundry)
• The Hybrid Car Analogy:
  Normally, our mitochondria should switch between fuel sources like a hybrid car switches between gas and battery. Most people’s “switch” is broken, particularly those who are overweight or obese.
  • “88% of overweight people can’t switch between burning sugar and burning fat…99.5% of obese individuals…cannot make that switch.” (03:40, Dr. Gundry)
• Why Fasting Often Feels Miserable:
  High insulin locks fat in fat cells and blocks ketone production. Many crash during fasting because their body can’t access alternative fuel.
  • "You don’t have any sugar…you don’t have any free fatty acids…you don’t have any ketones going to your brain. And what happens? You crash, you get headachy, you get weak, you get hangry.” (06:43, Dr. Gundry)

2. Making Fasting Easier & More Effective

Practical Approach for Beginners (08:19 - 12:20, 31:56 - 34:56)

• Go Slow:
  Instead of jumping to a 16:8 or 18:6 fasting protocol, extend breakfast by one hour per week.
  • “What I ask you to do is, one hour a week, extend when you’re going to have breakfast…week after week, will start to lower our insulin resistance.” (08:53, Dr. Gundry)
  • “For most of us, please, please, please do not jump off the deep end and try time restricted eating of six to eight hours a day. It’s going to not work. Instead, try time-restricted eating on a variable schedule of just extending your eating period one hour a week and watch what happens.” (12:16, Dr. Gundry)
• How to Handle Hitting a “Wall”:
  If you start feeling tired, headachy, or hungry after extending your fast, that’s a sign of ongoing insulin resistance. Use fasting-friendly “crutches” (see below), and hold at that window before advancing.
  • Mono Meals: First meal after fasting should be simple—pick mostly carbs, protein, or fat to ease digestion.

Tricks That Won’t Break Your Fast (15:13 - 26:01, 38:07)

• Safe Foods & Drinks:

  • Black coffee, unsweetened tea (polyphenols support mitochondria)
    • “Black coffee or tea with no sweeteners are the real deal. These can actually help with energy and mental focus while fasting.” (16:14, Dr. Gundry)
  • Heavy cream in small amounts (no sugar, but can bind polyphenols)
  • Allulose or monk fruit sweeteners (no effect on insulin or ketones)
  • A handful of nuts (pistachios, macadamias, Brazil nuts)
    • “He gave people who were fasting one of his nut bars…studied ketone production, and that bar did not break ketone production.” (21:17, Dr. Gundry)
  • MCT oil (especially C8), psyllium husk, basil seeds
  • Electrolyte powders without sugar or fake sweeteners

• Not So Fast:

  • Milk (contains sugar)
  • Collagen or protein supplements, flavored or sugary nuts, chewing gum (even sugar-free)
  • “Be wary of healthy ‘fasting drinks’ that contain collagen, protein, or flavor boosters with sugar or amino acids…Protein consumption ups your insulin production.” (25:00, Dr. Gundry)

3. Why Most Fasting Advice Fails for Real People (07:10 - 08:19, 31:28 - 34:56)

• Influencer Pitfalls:
  Most online fasting gurus are metabolically flexible and don’t represent typical Americans. Their advice can set up listeners for failure.

  • “When you see influencers…who tell you how easy it is…these are people who start with metabolic flexibility…” (08:19, Dr. Gundry)

• Dangers of Drastic Fasting Protocols:

  • Cutting your eating window too fast often leads to feeling terrible and giving up.
  • Prolonged water fasts can release stored toxins (heavy metals, pesticides) from fat cells, overwhelming detox systems.
    • “Right now, for Americans, water fasting is dangerous because of that fact.” (36:54, Dr. Gundry)
  • Fruit fasts or “detoxes” spike blood sugar, triglycerides, uric acid; one patient became diabetic.
    • “I think this is actually the worst idea.” (38:27, Dr. Gundry)

4. The Role of MCT Oil in Fasting and Health (15:13 - 15:13, 42:01 - 48:37)

• Unique Power of MCTs:
  • MCTs (especially C8) bypass normal fat digestion/absorption, go straight to the liver, and boost ketone production regardless of insulin.
  • Liquid MCT oil can cause GI distress for some, especially women; powdered is better tolerated.
    • “Taking MCT oil while you’re fasting is a great way to extend your fasting window and calm any cravings…” (43:57, Co-host)
• Olive Oil vs. MCT Oil:
  • MCTs outperform olive oil for fat loss and energy due to their thermogenic, “wasting calories” effect.
    • “The MCT group actually generated more body heat, burned more oxygen, and lost more weight…” (46:38, Co-host)

5. Gut “Buddies” & the Science of Cravings (22:26 - 26:01)

• Soluble Fiber for Hunger Control:
  • Soluble fibers (psyllium, basil seeds) feed gut bacteria, who signal the brain and suppress hunger.
    • “The group that got the hundred calories a day of, like, psyllium powder had no hunger for two weeks on a water fast.” (19:57, Dr. Gundry)
  • “The more we study…the deep connection between good guys in our gut and our hunger centers in our brain, we realize it's the gut bugs that are driving hunger.” (24:28, Dr. Gundry)

6. What is “Winning” at Fasting? (27:18 - 29:03)

• Not about Suffering:
  Don’t turn fasting into a contest or punishment. It’s about limiting the time you eat food, not starvation.
  • “The object of the game…this is not personal suffering…You’re not going on a religious quest.” (27:34, Dr. Gundry)
• Goal:
  Spend more hours per day in a fasting state, increasing ketone production for mitochondrial repair and longevity benefits.
  • “The more I can get you to a six to eight hour eating window, the better you’re going to do.” (29:32, Dr. Gundry)

Notable Quotes & Timestamps

• “The vast majority of people…are so metabolically inflexible that they absolutely do not do well with intermittent fasting. Shocking but true.” (02:06, Dr. Gundry)
• “You crash, you get headachy, you get weak, you get hangry. You just do not feel well. And that's your body saying, hey, I can't make this switch.” (06:43, Dr. Gundry)
• “I could have King James LeBron teach me how to dunk a basketball...I can't do that.” (08:19, Dr. Gundry)
• “Please, please, please do not jump off the deep end and try time restricted eating of six to eight hours a day. It's going to not work.” (12:16, Dr. Gundry)
• “Black coffee or tea with no sweeteners are the real deal. These can actually help with energy and mental focus while fasting.” (16:14, Dr. Gundry)
• “Fasting means that you are going to limit the amount of time during a 24 hour period where you’re not eating. That’s what that means.” (27:40, Dr. Gundry)
• “Now, as I show in my last two books, most of us are insulin resistant and metabolically inflexible. That means…when we stop eating, within a few hours, our glucose stores fall dramatically…But most of us can’t use fat as a fuel. So we crash…” (33:33, Dr. Gundry)
• “Prolonged water fasts…release not only fat from our fat cells, but those heavy metals and organopesticides. We have a horrible detoxification system.” (36:13, Dr. Gundry)
• “Fruit is loaded with fructose…Fructose is the best way to cause uric acid to increase in our blood, which causes gout and kidney stones and high blood pressure and diabetes…Their liver enzymes got worse, their uric acid levels went sky high, and one…became a diabetic.” (38:25, Dr. Gundry)
• “Taking MCT oil while you’re fasting is a great way to extend your fasting window and calm any cravings that you may be having.” (43:57, Co-host)

Important Timestamps

• [02:06] What really happens to your body during fasting
• [06:43] Symptoms of metabolic inflexibility during fasting (“hangry”, headachy, weak)
• [08:53] Dr. Gundry’s gradual fasting protocol: add one hour to breakfast each week
• [15:13] What technically breaks a fast—foods and drinks list
• [19:57] The gut-centric theory of hunger; fiber’s role in suppressing appetite
• [27:18] Fasting is not about suffering; it’s about metabolic repair
• [31:28] Three worst fasting trends to avoid (cutting window too drastically, prolonged water fasts, fruit detoxes)
• [42:01] The science and nuance of MCT oil
• [46:38] MCT oil vs. olive oil for fat loss and energy

Takeaway Strategies & Recommendations

• Start slow: Extend your overnight fast by one hour per week; don’t jump to drastic protocols.
• Watch for warning signs: Headaches, fatigue, and irritability mean your body isn’t metabolically flexible—don’t push through uncomfortably.
• Use fasting-friendly “crutches”: Black coffee, tea, MCT oil, nuts (in moderation), soluble fiber (psyllium, basil seeds), and unsweetened electrolyte powders.
• Avoid common fasting mistakes: Don’t do drastic water fasts, fruit juice fasts, or crash into short eating windows.
• Aim for metabolic flexibility: The real benefits start when fasting feels easy and cravings are gone—this shows your body is healthier.
• Let your “gut buddies” guide you: Feed your microbiome with soluble fiber to control hunger.
• If you want to use MCT oil: Choose powdered forms for gentler digestion, start with low doses, prioritize C8 MCT.

Final Thought

Dr. Gundry’s main message: Intermittent fasting is an incredibly powerful health tool—but only if you adapt the process to your actual metabolic state. Be patient, listen to your body, lean on science-backed crutches when needed, and allow yourself to progress at your own pace toward a sustainable, healthier lifestyle.