The 5-Step System That Will Reset Your Body & Help You Live Longer
In this episode of The School of Greatness, Dr. William Li and Lewis Howes explore the connection between gut health and longevity. They discuss how gut bacteria affect brain function, immune system response, and various chronic diseases, with Dr. Li explaining that 70% of the immune system resides in the gut and specific bacteria are consistently found in people who live past 100 years.
The discussion includes practical steps anyone can take to improve their gut health and potentially extend their lifespan. Dr. Li outlines dietary choices that support beneficial gut bacteria, including resistant starches and whole foods, while explaining why ultra-processed foods can damage the gut microbiome. He also covers the benefits of intermittent fasting, post-meal walks, and adequate sleep in maintaining a healthy gut environment.
This is a preview of the Shortform summary of the Aug 15, 2025 episode of the The School of Greatness
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1-Page Summary
Gut-brain Connection's Impact on Health and Longevity
In a conversation between Dr. William Li and Lewis Howes, they explore the fascinating relationship between gut bacteria and overall health, particularly focusing on brain function and longevity.
The Gut-Brain Connection
Dr. Li explains that gut health is intricately linked to brain function, with evidence showing that individuals with dementia often experience gut health issues. He reveals that the brain has its own microbiome of gut bacteria, and certain probiotics, like lactobacillus plantarum (PS128), may help slow down Parkinson's disease symptoms.
The connection goes deeper: Li notes that 70% of the immune system resides in the gut, where it continuously communicates with gut bacteria. This interaction influences various chronic diseases, including diabetes and cancer. Research on specific bacteria like Akkermansia shows promising results in improving immunity and fighting cancer.
The Longevity Connection
Dr. Li's research has identified four specific gut bacteria—Odoribacter, Oscillibacter, Christensenella, and Akkermansia—that are consistently found in centenarians and supercentenarians. These bacteria contribute to longevity by improving metabolism, lowering inflammation, and supporting brain health.
Practical Steps for Gut Health
Dr. Li recommends several practical approaches to nurture beneficial gut bacteria:
- Eat resistant starches found in green bananas, plantains, and cooled roasted potatoes
- Choose whole, fresh foods over ultra-processed options
- Consider occasional meal skipping, particularly breakfast, for intermittent fasting
- Take post-meal walks and get 7-9 hours of sleep
- Avoid harmful factors like smoking, vaping, and environmental toxins
Li emphasizes that ultra-processed foods can damage the gut microbiome through artificial preservatives and colorings, leading to inflammation and various health issues. He advocates for cooking meals at home and eating slowly, stopping before feeling completely full to prevent overconsumption.
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Counterarguments
- While the gut-brain connection is widely recognized, the extent to which gut health influences brain function and the development of neurological conditions like dementia is still under investigation. More research is needed to establish causation rather than correlation.
- The concept of the brain having its own microbiome is metaphorical; the actual microbiome resides in the gut, and its influence on the brain is through the production of metabolites and the immune system, not direct colonization of brain tissue.
- The efficacy of specific probiotics, such as lactobacillus plantarum (PS128), in slowing down Parkinson's disease symptoms may not be universally applicable and requires more extensive clinical trials to validate these findings.
- While a significant portion of the immune system is associated with the gut, stating that 70% resides there is an oversimplification, as the immune system is complex and distributed throughout the body.
- The role of specific bacteria like Akkermansia in fighting cancer and improving immunity is promising but not yet fully understood or conclusively proven in human studies.
- The association between certain gut bacteria and longevity in centenarians does not necessarily imply causation; these bacteria could be a result of other lifestyle factors that contribute to longevity.
- The recommendation to eat resistant starches for gut health, while beneficial, may not be suitable for everyone, especially those with specific dietary restrictions or carbohydrate-sensitive conditions.
- The advice to skip meals, such as breakfast, for intermittent fasting may not be appropriate for all individuals, particularly those with certain medical conditions or nutritional needs.
- The suggestion to take post-meal walks is generally positive, but the benefits can vary from person to person, and some may require different types or intensities of exercise.
- The recommendation for 7-9 hours of sleep is a general guideline, but individual sleep needs can vary, and some people may require more or less.
- The advice to avoid smoking, vaping, and environmental toxins is sound, but the text does not acknowledge the complexity of addiction or the socioeconomic factors that can make avoidance challenging.
- The claim that ultra-processed foods damage the gut microbiome and lead to inflammation may not account for the nuance that some processed foods can be part of a balanced diet or necessary for food security in certain populations.
- The recommendation to cook meals at home and eat slowly is ideal but may not consider time constraints, access to fresh ingredients, or culinary skills of individuals.
Actionables
- You can create a "gut diary" to track your food intake, mood, and physical symptoms, which can help you identify patterns and make connections between your diet and well-being. By noting down what you eat, how you feel afterward, and any changes in your physical health, you can pinpoint which foods may be nurturing your gut health and which ones might be detrimental. For example, if you consistently feel bloated after eating certain foods, you might consider reducing them in your diet.
- Experiment with incorporating one new source of resistant starch into your meals each week to diversify your gut bacteria. Start by adding a small portion of cooled roasted potatoes to your lunch or swapping your usual banana for a green one in your morning smoothie. This gradual approach allows your digestive system to adjust and can help you discover new foods that support your gut health without overwhelming you with changes.
- Engage in a "mindful eating challenge" where you focus on the sensory experience of eating, such as the taste, texture, and aroma of your food, to naturally slow down your eating pace and potentially reduce overconsumption. Set a timer for 20 minutes for each meal and aim to make your meal last the entire duration. This practice can help you become more attuned to your body's hunger and fullness signals, which is beneficial for gut health.
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Gut-brain Connection's Impact on Health and Longevity
Dr. William Lee and Lewis Howes discuss the growing evidence of the impact of gut bacteria on both brain health and overall well-being, highlighting the interconnectedness of the gut-brain axis.
Gut Bacteria Affect Brain and Neurological Health Via the Gut-brain Axis
Recent findings shed light on the complex relationship between gut bacteria and neurological health.
Gut Bacteria's Role in Dementia, Alzheimer's, and Parkinson's
William Li points out that individuals with dementia often present with gut health issues, suggesting a link between gut health and brain function. He hypothesizes that common neurodegenerative diseases like Parkinson's and Alzheimer's could be influenced by factors beyond commonly targeted molecules and proteins, with gut bacteria playing a significant role.
Mouth and Gut Bacteria Imbalances May Affect Brain Health
Li also addresses the role of oral health, indicating that conditions like gum disease and the imbalance of mouth bacteria might be trigger points for dementia. He introduces new findings suggesting that the brain has its microbiome consisting of gut bacteria, indicating that bacterial imbalances in the mouth or a lack of good bacteria in the gut may be triggers for Alzheimer's or Parkinson's disease. Specifically, he mentions lactobacillus plantarum (PS128), a probiotic that research has shown helps to slow down Parkinson's disease symptoms.
Gut Bacteria Influence Immune Communication, Affecting Health and Disease Risk
The way gut bacteria interact with our immune system may have far-reaching implications for our health and susceptibility to disease.
70% of the Immune System Is in the Gut, Where Bacteria Interact With Immune Cells
William Li emphasizes that a significant portion of the immune system resides in the gut, where it engages in constant communication with gut bacteria, much like college students conversing through a thin dorm wall. This crucial interaction can influence various chronic diseases, including diabetes and cancer, which are closely tied to the immune system's performance.
Gut Bacteria Like Akkermansia Impact Immunity, Fight Cancer
Li is involved in research focusing on gut bacteria such as Akkermansia, highlighting their role in immunity and their potential in combating cancer. He notes that consumption of dietary fiber—a key component for a healthy gut microbiome—improves ...
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Gut-brain Connection's Impact on Health and Longevity
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Counterarguments
- While there is evidence suggesting a link between gut health and neurological conditions, it is important to note that correlation does not imply causation, and more research is needed to establish a direct causal relationship.
- The complexity of the gut-brain axis means that while gut bacteria may play a role in brain health, there are many other factors, such as genetics and lifestyle, that also significantly contribute to neurological conditions.
- The idea that the brain has its microbiome is a relatively new and not widely accepted concept in the scientific community, and more evidence is needed to support this claim.
- While Lactobacillus plantarum (PS128) has shown promise in some studies, it is not a universally accepted treatment for Parkinson's disease, and more rigorous clinical trials are necessary to confirm its efficacy and safety.
- The statement that 70% of the immune system is in the gut is an oversimplification, as the immune system is a complex network that cannot be quantified in such a straightforward manner.
- The role of specific bacteria like Akkermansia in fighting cancer is an area of ongoing research, and while there are promising findings, these should not be interpreted as definitive proof or a standalone treatment option.
- The connection between mental health issues and gut health is an emerging field of study, and while there are associations, the exact nature of these relationships is still being understood, and other factors ...
Actionables
- You can enhance your gut-brain health by starting a "Fiber Fridays" tradition where you incorporate a new high-fiber food into your meals every Friday, such as legumes, berries, or whole grains, to potentially improve your gut microbiome and, by extension, your brain health.
- By dedicating one day a week to focus on high-fiber foods, you create a manageable and sustainable habit that can lead to long-term dietary changes. This practice can make it easier to track changes in your well-being and identify which foods make you feel better mentally and physically.
- Create a "Mouth Microbiome Morning Routine" by using a tongue scraper and an alcohol-free, microbiome-supporting mouthwash daily to potentially balance oral bacteria and contribute to overall brain health.
- Integrating these tools into your morning routine can be a simple yet effective way to support your oral microbiome. The tongue scraper can reduce the buildup of bacteria on the tongue, and the mouthwash can help maintain a healthy balance of oral bacteria, which may have downstream effects on brain health.
- Initiat ...
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Gut Bacteria's Role in Longevity and Disease Prevention
Gut health has a significant role in longevity, with researchers such as Dr. William Li discovering that certain gut bacteria are more prevalent in individuals who live to be 100 years or older.
Centenarians, Supercentenarians Have Unique Gut Bacteria Profiles Compared To Younger Individuals
Dr. Li and his team investigate the gut microbiome of those who live beyond a century. They have identified four specific gut bacteria—Odoribacter, Oscillibacter, Christensenella, and Akkermansia—that stand out in people who reach such advanced ages.
Gut Bacteria Linked To Longevity: Odoribacter, Oscillibacter, Christensenella, Akkermansia
These bacteria are linked to functions that contribute to longevity by improving metabolism, lowering inflammation, aiding immunity, reducing cholesterol, and supporting brain health. A study from Italy spanning various ages, including supercentenarians aged 100 to 115, found that these four bacteria are key components in the guts of those who have lived exceptionally long lives.
Nurture Gut Bacteria Through Diet and Lifestyle
Dr. Li recommends dietary and lifestyle changes that could nurture beneficial gut bacteria and potentially add healthy years to our lives.
Resistant Starches in Bananas and Potatoes Promote Akkermansia Growth
Diet plays a crucial role in fostering a healthy gut microbiome. Consuming resistant starches, like those found in green bananas, plantains, and cooled roasted potatoes, can promote the growth of healthy gut bacteria commonly found in supe ...
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Gut Bacteria's Role in Longevity and Disease Prevention
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Clarifications
- These specific gut bacteria, Odoribacter, Oscillibacter, Christensenella, and Akkermansia, are linked to longevity by improving metabolism, reducing inflammation, supporting immunity, lowering cholesterol levels, and promoting brain health. They play crucial roles in maintaining overall health and well-being, contributing to a longer and healthier lifespan. Studies have shown that individuals with higher levels of these bacteria tend to live longer, healthier lives compared to those with lower levels. By nurturing these beneficial gut bacteria through diet and lifestyle choices, individuals may potentially enhance their longevity and overall health.
- Resistant starches are a type of carbohydrate that resist digestion in the small intestine, reaching the colon intact. Once in the colon, they serve as food for beneficial gut bacteria, promoting their growth and activity. Foods rich in resistant starches include green bananas, plantains, and cooled roasted potatoes. By consuming these foods, individuals can support a healthy gut microbiome, which is linked to various health benefits, including longevity.
- Ultra-pro ...
Counterarguments
- The correlation between specific gut bacteria and longevity does not necessarily imply causation; other factors may contribute to the longevity of centenarians and supercentenarians.
- The gut microbiome is highly individual and influenced by a variety of factors, including genetics, environment, and lifestyle, which may not be fully accounted for in studies.
- While resistant starches can promote the growth of beneficial gut bacteria, individual responses to dietary changes can vary, and what works for one person may not work for another.
- The recommendation to avoid ultra-processed foods, while generally sound, may oversimplify the complexity of dietary influences on the gut microbiome and overall health.
- The impact of specific foods like pomegranate juice and dried cranberries on gut health may not be as significant when considering the entirety of an individual's diet and lifestyle.
- The advice to us ...
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Lifestyle Factors That Influence Gut Health and Longevity
William Li and Lewis Howes discuss necessary dietary and lifestyle changes to nurture the gut microbiome, emphasizing how these changes can lead to better overall health and longevity.
Whole Foods Impact Gut Microbiome
Li underscores the significance of a diet based on plant-based whole foods and the necessity of cooking them personally, in contrast to the negative impacts of consuming ultra-processed foods. He distinguishes between processing and ultra-processing, with the latter involving factory extrusion and the addition of flavors, colorings, stabilizers, and harmful chemical components. Li implies that whole, fresh foods provide nourishing compounds that benefit gut health, contrasting with ultra-processed foods, which can cause internal damage in known and yet-to-be-discovered ways. Li cautions against overconsumption of ultra-processed foods, which are easily accessible and cheap but damaging to the gut microbiome. He states that artificial preservatives and coloring found in these foods can kill beneficial gut bacteria.
Ultra-Processed Foods Harm Gut Bacteria, Causing Inflammation and Health Issues
Ultra-processed foods are trashing the body from the inside out, negatively impacting thoughts and creating issues both in the gut and the brain. Li's advice revolves around eating whole foods and avoiding ultra-processed foods as a crucial step toward maintaining a healthy gut and mind. He elucidates that consuming ultra-processed foods can thwart satiety signals, leading to overeating.
Eat Slowly and Stop Before Full to Prevent Overconsumption
Li also advises stopping before being fully satiated and encourages eating slowly to manage food consumption better. His approach emphasizes that optimizing longevity involves working with the body's natural systems, including dietary habits, to improve brain and immune system functions related to gut health.
Fasting, Exercise, and Sleep Nurture Gut Health and Longevity
Skipping breakfast is the easiest meal to omit for those interested in effortless intermittent fasting, thus extending the fasting period to around 12 hours. An incidental approach to intermittent fasting is to skip breakfast or another meal a couple of times a week.
Skipping Breakfast to Incorporate Intermittent Fasting
Li encourages skipping meals occasionally. Specifically, he suggests that breakfast is the easiest meal to skip to initiate intermittent fasting.
Post-Meal Walks and 7-9 Hours of Sleep Optimize Gut and Health
Li advocates for walking after meals, particularly after dinner, which is an accessible form of exercise that anyone can perform. Li st ...
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Lifestyle Factors That Influence Gut Health and Longevity
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Counterarguments
- While plant-based whole foods are beneficial, some individuals may require animal proteins and nutrients that are more readily available in meat and dairy products for their unique health needs.
- Not all ultra-processed foods are equally harmful; some may be fortified with vitamins and minerals that can be beneficial, especially in populations with limited access to fresh whole foods.
- The relationship between ultra-processed foods and health issues is complex and may also involve factors such as genetics, lifestyle, and socioeconomic status.
- Eating slowly and stopping before fullness is a good general guideline, but some individuals with high metabolic demands or nutritional deficiencies might need to eat more frequently or to full satiety.
- Intermittent fasting may not be suitable for everyone, such as those with certain medical conditions, pregnant women, or individuals with a history of eating disorders.
- Skipping breakfast as a form of intermittent fasting may not align with the circadian rhythm and metabolic needs of all individuals, and some studies suggest that a healthy breakfast can contribute to better weight management and nutrient intake.
- While walking after meals is beneficial, it may not be the optimal form of exercise for everyone, and some individuals may benefit more from higher intensity workouts or resistance training.
- The recommendation of 7-9 hours of sleep is a general guideline, but individual sleep needs can vary, and some people may require more or less sleep for optimal health.
- The impact of smoking, vaping, and pollutants on gut health is well-established, but the degree of impact can vary greatly among individuals du ...
Actionables
- Create a "gut-friendly" recipe swap club with friends to explore and share homemade plant-based meals, encouraging each other to cook from scratch and discover new, wholesome dishes that support gut health.
- By exchanging recipes and hosting regular potlucks, you'll expand your culinary repertoire with foods that are beneficial for your gut. This social approach makes the transition to whole foods enjoyable and sustainable, as you learn from each other's cooking experiences and preferences.
- Designate a "mindful eating zone" in your home where distractions like TV and smartphones are not allowed, fostering an environment that encourages eating slowly and attentively.
- This dedicated space can be a simple corner of your dining area with comfortable seating and pleasant decor. The absence of distractions will help you focus on the flavors and textures of your food, promoting better digestion and preventing overeating by allowing your body to recognize fullness cues.
- Initiate a "green commute" challenge where ...
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