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Effects of Fasting & Time Restricted Eating on Fat Loss & Health | Huberman Lab Podcast #41

Andrew Huberman・119 minutes read

The Huberman Lab Podcast covers various aspects of fasting and its effects on health, including weight loss, organ health, metabolism, and performance, promoting specific time-restricted feeding schedules to maximize benefits. Understanding the mechanisms and tools associated with time-restricted feeding can positively impact overall health, weight loss, and metabolic health, emphasizing the importance of precision in terminology and implementing fasting strategies.

Insights

  • Time-restricted feeding, also known as intermittent fasting, involves specific eating periods within a 24-hour cycle or fasting for entire days, impacting various health aspects like weight loss, muscle maintenance, organ health, and cognition.
  • Specific schedules of time-restricted feeding can influence health in diverse ways, affecting weight loss, muscle maintenance, organ health, genome, inflammation, sickness, recovery, exercise, cognition, mood, and lifespan.
  • Various tools discussed in the episode can help mitigate negative health effects of strict feeding or fasting schedules, promoting health, weight loss, and performance by tricking the body into a state of fasting.
  • Understanding biological mechanisms and tools is crucial for implementing discussions on feeding, fasting, health, and performance effectively, emphasizing the importance of precision in terminology.
  • An eight-hour feeding window is recommended for most individuals, including athletes and those under high stress, impacting hormone health, body composition, performance, and metabolic health positively.

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Recent questions

  • What is time-restricted feeding?

    Time-restricted feeding, also known as intermittent fasting, involves eating within specific time frames during a 24-hour cycle or fasting for extended periods. This approach can impact various aspects of health, including weight loss, muscle maintenance, organ health, genome, epigenome, inflammation, sickness, recovery, exercise, cognition, mood, and lifespan.

  • How does time-restricted feeding affect health?

    Time-restricted feeding can positively influence health parameters such as weight loss, fat loss, muscle maintenance, organ health, genome, epigenome, inflammation, sickness, recovery, exercise, cognition, mood, and lifespan. By adhering to specific feeding schedules, individuals can mitigate negative health effects and promote overall well-being.

  • What are the benefits of an eight-hour feeding window?

    An eight-hour feeding window is recommended for most individuals as it allows for optimal intermittent fasting benefits without social disruptions. This timeframe aligns with the body's natural fasting and digestion processes, promoting regular gene expression and improved health outcomes in both mice and humans.

  • How can one transition into a time-restricted feeding schedule?

    Transitioning gradually into a time-restricted feeding schedule over several days is advised to allow the body's hormone systems to adjust. Shifting the feeding window by about an hour daily during the transition period can help individuals adapt to the new schedule comfortably.

  • What tools can help regulate blood glucose levels during fasting?

    Glucose disposal agents like Metformin and berberine, along with behaviors like post-meal walks, can assist in regulating blood glucose levels and supporting fasting periods. These tools can aid in transitioning the body from a fed to a fasted state effectively.

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Summary

00:00

"Science-based tools for health and performance"

  • The Huberman Lab Podcast discusses science and science-based tools for everyday life, hosted by Andrew Huberman, a Professor of Neurobiology and Ophthalmology at Stanford School of Medicine.
  • The episode focuses on fasting and its impact on health and wellbeing, covering topics like weight loss, muscle maintenance, organ health, genome, epigenome, inflammation, sickness, recovery, exercise, cognition, mood, and lifespan.
  • Intermittent fasting, also known as time-restricted feeding, involves eating at specific periods within a 24-hour cycle or fasting for entire days.
  • Specific schedules of time-restricted feeding can influence health in various ways, affecting weight loss, fat loss, muscle maintenance, organ health, genome, epigenome, inflammation, sickness, recovery, exercise, cognition, mood, and lifespan.
  • Various tools discussed in the episode can help mitigate negative health effects of strict feeding or fasting schedules, making the body think it did not eat at all, which can be beneficial for health, weight loss, and performance.
  • A study published in Cell Metabolism titled "Fasting Blood Glucose as a Predictor of Mortality: Lost in Translation" found that higher blood glucose levels in humans are associated with mortality, contrasting with results in mice where lower blood glucose was linked to mortality.
  • The podcast is separate from Huberman's roles at Stanford and aims to provide free science-related information to the public.
  • Sponsors of the podcast include ROKA for eyeglasses and sunglasses, InsideTracker for personalized nutrition analysis, and Helix Sleep for customized mattresses and pillows.
  • Huberman emphasizes the importance of understanding biological mechanisms and tools for implementing them in discussions on feeding, fasting, health, and performance.
  • The episode introduces foundational terms like time-restricted feeding and fasting, highlighting the importance of precision in terminology and discussing various fasting schedules and their effects on health.

13:01

Understanding mechanisms for optimal health and weight.

  • Understanding mechanisms provides flexibility and control over mental and physical health.
  • Listing off tasks without understanding lacks depth for navigating life's challenges.
  • A study by Chris Gardner in 2018 compared weight loss on different diets.
  • The study found no significant difference in weight loss between low-fat and low-carb diets.
  • Factors like exercise, metabolic rate, and hormones impact calorie burning.
  • Hormones like thyroid, insulin, and growth hormone influence calorie expenditure.
  • The ideal diet varies based on individual factors and context.
  • Eating impacts blood glucose and insulin levels, influenced by food types.
  • Time-restricted feeding can positively impact weight loss and health parameters.
  • Satchin Panda's study in 2012 on mice showed time-restricted feeding prevented metabolic diseases without reducing calories.

27:29

Time-Restricted Feeding Improves Health and Weight

  • Mice were given access to different diets, including a high-fat diet, either ad libitum or within restricted time frames.
  • Mice that consumed a high-fat diet within a restricted feeding window maintained or lost weight, while those with 24-hour access gained weight and became obese.
  • Mice that ate within an eight-hour window showed improvements in health markers and even reversed some negative health effects.
  • The eight-hour feeding window was chosen due to practical constraints in research, not due to any inherent significance.
  • Eating during the active phase of the day is crucial for health, with nocturnal eating being detrimental.
  • Restricting food intake to specific time frames led to regular gene expression and improved health outcomes in mice and humans.
  • Time-restricted feeding positively impacted liver health by reducing fatty deposits and improving metabolic functions.
  • Eating around the clock increased inflammatory markers, leading to negative health consequences, while restricted eating periods promoted health.
  • Absolutes in time-restricted feeding include not eating for the first hour after waking and avoiding food for two to three hours before bedtime.
  • Establishing a foundational protocol for time-restricted feeding can help maximize health goals, including weight maintenance and metabolic health.

41:08

Optimal Timing for Intermittent Fasting Benefits

  • Research indicates not eating for the first 60 minutes after waking up is beneficial for various health parameters.
  • The ideal time for the eating window in intermittent fasting is best determined by considering the fasting period.
  • A recent review in the journal Endocrinology Reviews by Satchin Panda's lab provides extensive data on time-restricted eating.
  • Fasting during sleep enhances autophagy and cellular repair processes.
  • Extending the fasting period beyond waking up can maximize the benefits of sleep-related fasting.
  • Starting the feeding window early in the day or in the evening aligns with the body's natural fasting and digestion processes.
  • Eating late in the day can disrupt the fasting-related benefits of sleep.
  • A feeding window from around noon to 6 or 8 PM allows for optimal intermittent fasting benefits without social disruptions.
  • Food volume and type impact the transition from a fed to a fasted state, with larger meals taking longer to digest.
  • Learning to gauge food volume is crucial for effectively transitioning into a fasted state.

54:26

"Optimal Feeding Windows for Health and Fitness"

  • Foods with varying fat content affect gastric emptying time; meals with more fats take longer to digest.
  • Liquid calories speed up gastric emptying time compared to solid foods.
  • Combining fats with sugars leads to a gradual rise in glucose levels.
  • Establishing a manageable feeding window is crucial for dietary success.
  • People tend to underestimate their actual feeding window duration.
  • Selecting a slightly shorter feeding window accounts for inevitable eating outside the window.
  • Rules for an ideal fasting schedule include no food for an hour after waking and 2-3 hours before bedtime.
  • Opting for a shorter feeding window allows for a taper into the fasting state.
  • Short feeding windows of 4-6 hours show positive health effects but may lead to overeating.
  • Ingesting protein early in the day supports muscle maintenance and growth, particularly for hypertrophy training.

01:08:06

Optimizing Intermittent Fasting Schedule for Health

  • Transition period of 1 week to 10 days needed for changing intermittent fasting schedule
  • Shift feeding window by about an hour daily during transition
  • Maintain comfortable feeding window for at least 30 days, ideally indefinitely
  • Data from My Circadian Clock experiment shows people often eat in broader windows than perceived
  • Strict feeding window adherence crucial for clock gene expression
  • Drifting feeding windows, especially on weekends, disrupt circadian clock mechanisms
  • Consistent feeding window placement within 24-hour cycle vital for health benefits
  • Light walk post-meal accelerates transition from fed to fasted state
  • High-intensity interval training impacts blood glucose levels based on timing
  • Engaging in high-intensity interval training in the afternoon or evening aids in glucose clearing and transition to fasted state

01:21:02

"Optimizing Blood Glucose Levels with Supplements"

  • Glucose disposal agents like Metformin or berberine can dramatically reduce blood glucose levels, shifting the body from a fed to a fasted state.
  • Berberine, similar to Metformin but cheaper and over-the-counter, can cause hypoglycemia and headaches if taken without ingesting carbohydrates.
  • Responses to berberine and Metformin vary among individuals, with a strong circadian component influencing their effects.
  • Continuous glucose monitors provide valuable insights into how different foods, exercises, and supplements impact blood glucose levels.
  • Glucose clearing agents through exercise are easier to adjust than those taken orally, which can have varying effects on blood glucose levels.
  • Fasting reduces the activity of the protein MTOR, associated with cell growth, while promoting the expression of proteins like AMPK and sirtuins linked to cell repair and autophagy.
  • Intermittent fasting can improve gut health by modulating clock genes and promoting a healthier gut microbiome.
  • Non-alcoholic fatty liver disease is linked to brown fat levels, with time-restricted feeding and cold exposure potentially increasing brown fat stores and reducing liver disease risk.
  • Time-restricted feeding has positive effects on insulin profiles and hormonal parameters, potentially impacting performance, immune function, and body composition.
  • A study on elite cyclists showed that time-restricted eating led to significant decreases in free testosterone levels compared to a control group with the same caloric intake.

01:34:20

Hormonal Impact of Time-Restricted Feeding

  • Time-restricted feeding may not be suitable for everyone due to individual variations in hormone levels and responses.
  • Monitoring one's hormonal profile through blood work is crucial to understanding the impact of time-restricted feeding.
  • Cortisol, a stress hormone, plays a significant role in the body's response to feeding windows and can affect overall health.
  • Time-restricted feeding can lead to reductions in cortisol levels, potentially offsetting the decrease in testosterone.
  • A comprehensive analysis of various hormones is essential to grasp the full impact of time-restricted feeding on the body.
  • Time-restricted feeding has shown compatibility with quality hormone health, even in high-performing athletes.
  • An eight-hour feeding window is recommended for most individuals, including athletes and those experiencing high stress levels.
  • Hormone health, particularly in relation to reproductive functions, is influenced by body fat levels and eating patterns.
  • Transitioning gradually into a time-restricted feeding schedule over several days is advised to allow the body's hormone systems to adjust.
  • Studies have highlighted the effectiveness of an eight-hour time-restricted feeding window in promoting weight loss and improving metabolic health in obese adults.

01:47:25

"Time-restricted feeding boosts fat loss efficiency"

  • Time-restricted feeding and fasting provide mental clarity by eliminating the need to constantly make decisions about when to eat.
  • A set eating window in time-restricted feeding removes the need for negotiating portion sizes and food choices.
  • Food choices within the feeding window impact blood glucose levels, affecting hunger and metabolic processes.
  • Time-restricted feeding reduces the cognitive load of decision-making by bypassing the need for constant behavioral regulation.
  • Long-term adherence to time-restricted feeding may lead to metabolic changes favoring fat loss over other tissue loss during caloric restriction.
  • Time-restricted feeding shifts energy metabolism towards increased fat loss by altering hepatic lipase and CIDEC levels.
  • The effectiveness of time-restricted feeding in promoting fat loss is supported by scientific evidence over other feeding schedules.
  • Determining what breaks a fast is context-dependent, influenced by factors like glucose levels, meal timing, and activity levels.
  • Consuming sugar post-meal can disrupt fasting-related gene expression, highlighting the sensitivity of the body's fasting state.
  • Artificial sweeteners like Stevia may have minimal impact on blood glucose levels during fasting, but moderation is key to avoid potential negative effects on the gut microbiome.

02:00:51

Optimizing intermittent fasting for appetite control

  • Some individuals experience increased appetite after consuming something sweet, making it challenging to stick to a feeding window.
  • Conducting a well-controlled study on this topic is complex due to individual variations in adherence to feeding windows, blood glucose fluctuations, exercise habits, etc.
  • Artificial sweeteners may not necessarily break a fast, contrary to popular belief.
  • Certain substances like cinnamon, lemon/lime juice, and salt can impact blood glucose levels.
  • Salt can aid in managing fasting periods by stabilizing blood volume and offsetting low blood sugar symptoms.
  • Saltwater with lemon/lime juice can help stabilize blood glucose levels and reduce shakiness during fasting.
  • My Circadian Clock website and the Zero app are valuable resources for time-restricted feeding.
  • Brushing teeth with toothpaste does not break a fast unless the toothpaste is swallowed.
  • Consuming a half glass of wine with sugar content after dinner can break a fast due to its impact on blood glucose levels.
  • Ideal intermittent fasting involves avoiding food for at least 60 minutes upon waking, abstaining from food for 2-3 hours before bedtime, and aiming for an 8-hour feeding window.

02:13:41

Optimizing Feeding Windows for Health Benefits

  • One meal per day eating patterns may not lead to overeating or weight gain, but most people struggle to maintain this schedule regularly due to social constraints.
  • There is limited research on the benefits of one meal per day eating patterns compared to an eight-hour feeding window.
  • To avoid overeating, individuals can opt for a one meal per day approach or a four to six-hour feeding window, ensuring moderation within that timeframe.
  • Many individuals tend to eat outside of their designated eight-hour feeding window, so adjusting the window to a shorter duration may be beneficial.
  • Consistent placement of the eating window within a 24-hour cycle is crucial to maximize the benefits of time-restricted feeding and avoid disrupting circadian rhythms.
  • Ideal placement of an eight-hour feeding window involves starting at 10:00 AM and ending at 6:00 PM, although this may not be practical for everyone.
  • Some individuals may benefit from starting their feeding window later in the day, such as at 12:00 PM or 2:00 PM, depending on personal preferences and exercise routines.
  • Protein ingestion early in the day may be advantageous for individuals focusing on muscle hypertrophy, as it can aid in muscle tissue conversion.
  • Glucose disposal agents like Metformin and berberine, along with behaviors like post-meal walks, can help regulate blood glucose levels and support fasting periods.
  • Artificial sweeteners in moderation may not significantly impact blood glucose levels during fasting, but individual responses may vary, necessitating self-experimentation to determine ideal nutrition schedules.
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