#066 Dr. Mark Mattson on the Benefits of Stress, Metabolic Switching, Fasting, and Hormesis
Dr. Mark Mattson, a Johns Hopkins neuroscientist, discusses how hormetic stressors like intermittent fasting and exercise drive adaptation and prevent physiological complacency. He explains metabolic switching, compares fasting protocols, and highlights additive benefits of combining these stressors with plant-based compounds for brain and overall health.
Deep Dive Analysis
17 Topic Outline
Introduction to Dr. Mark Mattson's Research and Expertise
Why Humans Need Biological Stress: Evolutionary Perspective
Modern Society's Impact on Cellular Complacency and Disease
Benefits of Exercise on Muscle and Brain Cells
Understanding Different Intermittent Fasting Eating Patterns
Historical Context and Popularization of Intermittent Fasting
Adaptation to Intermittent Fasting and Neuroendocrine Changes
Ketogenic Diet vs. Intermittent Fasting for Brain Health
Additive Effects of Exercise and Intermittent Fasting
Importance of Refeeding and Recovery Periods in Fasting
Plant-Based Bioactive Compounds as Hormetic Stressors
Intermittent Fasting in Healthy Individuals vs. Metabolically Unhealthy
Maintaining Muscle Mass and Fasting in Older Adults
Intermittent Fasting in Women, Children, and Pregnant Women
Cortisol Effects: Fasting vs. Chronic Uncontrollable Stress
Cardiovascular Benefits of Intermittent Fasting and Exercise
Fasting Mimetics vs. Actual Fasting and Ketone Esters
7 Key Concepts
Hormesis
Hormesis refers to the process where mild, transient stressors, like those encountered during evolution (e.g., food scarcity, exercise), trigger adaptive responses in cells. These responses make cells stronger and more resilient, helping them cope with more severe stresses and prevent physiological complacency.
Metabolic Switching
This is a key process in intermittent fasting where the body depletes its glucose stores in the liver and switches to using fats from fat cells and ketones produced from those fats as its primary energy source. This switch typically takes at least 10 hours of not eating.
BDNF (Brain-Derived Neurotrophic Factor)
BDNF is a neurotrophic factor, a protein produced in the brain in response to neural network activity and metabolic stresses like exercise and fasting. It is essential for learning, memory, and the formation of new synapses between nerve cells, and also plays a role in regulating appetite.
Glutamate
Glutamate is the most important excitatory neurotransmitter in the brain, deployed by at least 90% of nerve cells. It is critical for learning and memory and is involved in synaptic remodeling, but excessive or prolonged excitation (excitotoxicity) can be damaging to neurons, especially in compromised states.
GABA (Gamma-Aminobutyric Acid)
GABA is the main inhibitory neurotransmitter in the brain, distributed throughout. Its primary role is to control the excitability of glutamatergic neurons, preventing over-excitation and maintaining optimal brain function. Drugs like benzodiazepines activate GABA receptors to quiet down neural activity.
Cytochrome P450s
These are enzymes found in the liver that have evolved to rapidly remove potentially toxic chemicals, including naturally occurring pesticides found in plants, from the body when consumed. They represent one of the body's adaptive mechanisms to co-evolve with plant materials.
Heart Rate Variability
Heart rate variability refers to the variation in the time interval between individual heartbeats. High heart rate variability, often seen in endurance athletes, indicates that the heart's regulation is more adaptable to stress and other physiological changes, reflecting enhanced parasympathetic nervous system activity.
11 Questions Answered
Humans evolved in stressful environments, and organisms developed mechanisms not only to resist toxic exposures but to benefit from them. Biological stress, like food scarcity and physical exertion, motivated survival and led to the evolution of systems that thrive under such conditions.
Modern society provides constant access to food and reduces the need for physical exertion, leading to cellular complacency. This lack of intermittent stress means cells do not maintain their ability to cope with stressors like oxidative stress and inflammation, which can contribute to disease.
Common intermittent fasting patterns include daily time-restricted eating (compressing eating into a 6-8 hour window) and 5-2 intermittent fasting (eating one moderate 600-calorie meal two days a week and normally for five days).
It typically takes about two weeks to a month for the body's systems, including neuroendocrine systems controlling hunger and satiety, to adapt to a new eating pattern like intermittent fasting, after which initial hunger and irritability subside.
A ketogenic diet can provide some, but not all, of the benefits of intermittent fasting. While ketones are an efficient energy source for neurons and have signaling functions, intermittent fasting also promotes increased neural network activity and a broader range of beneficial signaling functions that a ketogenic diet alone may not.
Yes, studies in animals show that combining exercise with intermittent fasting can lead to additive benefits, such as a greater increase in the number of synapses and BDNF levels in the brain, and improved endurance and mitochondrial function in muscle cells, compared to either intervention alone.
Fruits and vegetables are beneficial not primarily because of their antioxidant properties, but because they contain naturally occurring chemicals (plant toxins/pesticides) that act as mild stressors. These chemicals trigger adaptive stress responses in our cells, enhancing antioxidant defenses and other protective mechanisms, similar to exercise and fasting.
No, plant phytochemicals do not substitute for exercise or intermittent fasting. While they activate some stress response pathways, these chemicals are more targeted and affect a more limited number of pathways compared to the broader systemic effects of exercise and fasting. A diversified approach combining all three is likely most beneficial.
While intermittent fasting can elevate cortisol levels, the cellular response to this stress is different from chronic uncontrollable stress. Intermittent fasting causes a decrease in the glucocorticoid receptor (GR) and sustained mineralocorticoid receptor (MR) levels in brain cells, indicating an adaptive, beneficial response, unlike the detrimental changes seen with chronic stress.
In animal studies, severe caloric restriction (e.g., 40% daily) can shut down estrus cycles in females but not affect male fertility. However, alternate-day fasting allowed females to maintain cycling, albeit with some irregularity. The impact on women's cycles and hormones appears to be more related to the overall caloric deficit rather than the fasting pattern itself, especially in non-adolescent, non-calorically restricted women.
Yes, ketone supplementation, particularly with ketone esters, shows promise for improving brain health. Animal studies in Alzheimer's models demonstrated beneficial effects on amyloid accumulation, tau pathology, and learning/memory. In humans, brain cells with early Alzheimer's disease, despite having problems using glucose, appear to utilize ketones very well, suggesting a potential therapeutic avenue.
18 Actionable Insights
1. Regular Physical Exercise for Cellular Resilience
Engage in regular physical exercise to stress muscle cells, which activates gene programs that increase antioxidant defenses, clear damaged proteins and dysfunctional mitochondria, and produce protective heat shock proteins, making cells stronger and more resilient.
2. Intellectual Engagement for Brain Health
Keep your mind intellectually engaged through activities like conversations or learning to increase electrical activity in nerve cells, which boosts mitochondrial function and can increase the number of synapses, improving brain resilience.
3. Practice Intermittent Fasting for Metabolic Switching
Adopt an eating pattern that includes intermittent periods of not eating for at least 10 hours to deplete liver glucose stores, causing a metabolic switch to burning fat and producing ketones, which is important for health benefits.
4. Implement Daily Time-Restricted Eating
Compress your daily eating window to 6-8 hours (e.g., eating between noon and 6 p.m. and skipping breakfast) to achieve a 16-18 hour fast, which is sufficient to induce daily metabolic switching and elevate ketone levels.
5. Combine Fasting with Morning Exercise
Exercise in a fasted state, such as a morning run after an overnight fast, to enhance the elevation of ketones and potentially amplify beneficial effects on the brain, cardiovascular system, and physical performance.
6. Adopt a Predominantly Plant-Based Diet
Prioritize a diet that is mostly plant-based, minimizes simple sugars and saturated fats, and favors fish over red meat, as this aligns with patterns observed in populations with exceptional longevity and supports overall health.
7. Consume Plant-Based Bioactive Compounds
Incorporate fruits and vegetables containing naturally occurring phytochemicals (e.g., sulforaphane in broccoli, curcumin in turmeric, caffeine) into your diet, as these compounds trigger mild adaptive stress responses in cells, enhancing antioxidant defenses and cellular resilience.
8. Prioritize Muscle Mass Maintenance
Be mindful of maintaining sufficient muscle mass as you age, ensuring adequate energy intake and potentially incorporating resistance training, especially if you have a low BMI or are undergoing significant weight loss.
9. Utilize Sauna or Hot Baths
Use saunas or hot baths to mimic the cardiovascular benefits of aerobic exercise, including enhanced parasympathetic activity, improved heart rate variability, and reduced blood pressure, which is especially useful for maintaining muscle mass and recovery when injured.
10. Allow 2-4 Weeks for Fasting Adaptation
Expect initial hunger and irritability for the first 2-4 weeks when starting an intermittent fasting regimen, as it takes time for the body and brain’s neuroendocrine systems to adapt to the new eating pattern.
11. Try 5-2 Weekly Intermittent Fasting
For two days a week, consume only one moderate-sized meal of approximately 600 calories, while eating normally on the other five days, to induce metabolic switching on those two fasting days.
12. Diversify Hormetic Stressors for Health
Combine different types of hormetic stressors, such as exercise, intermittent fasting, and plant-based phytochemicals, because each may activate distinct or more robust stress response pathways, leading to a broader range of health benefits.
13. Avoid Overdoing Prolonged Fasting
Do not attempt extreme prolonged fasting regimens (e.g., 5 days fasting with only 1 day recovery repeatedly) as this can lead to significant problems and long-term adverse consequences, including muscle loss.
14. Exercise Caution with Fasting Mimetics
Exercise caution and avoid relying on ‘fasting mimetics’ like 2-deoxyglucose, nicotinamide riboside, or rapamycin for long-term health benefits, as there is insufficient data in humans to support their safe and effective use, and some have shown adverse long-term effects.
15. Ketogenic Diet for Partial Benefits
While a ketogenic diet can provide some benefits like efficient energy for neurons and signaling functions from ketones, it may not offer the full range of benefits seen with intermittent fasting, such as increased neural network activity and broader neurotrophic factor activation.
16. IF for Overweight Children (Supervised)
For overweight or obese children, intermittent fasting, with parental buy-in and under the guidance of a pediatrician, has shown success in helping kids reduce body weight by switching their eating patterns.
17. Engage in Exercise During Pregnancy
Pregnant women should engage in some exercise during pregnancy, contrary to older advice, as it is beneficial for their health.
18. Consider Ketone Esters for Neurological Symptoms
Explore the use of ketone esters, which have shown promising beneficial effects in animal models of Alzheimer’s disease and anecdotally for symptoms of Parkinson’s disease and essential/orthostatic tremors, by rapidly inducing ketosis.
6 Key Quotes
Intermittent fasting is an eating pattern, it's not a diet.
Dr. Mark Mattson
The stress of the food scarcity is actually a motivating factor, and nervous systems evolved to overcome food scarcity in many different ways.
Dr. Mark Mattson
When we have food available all the time and when we don't have the need to exercise to get through life, our cells become complacent.
Dr. Mark Mattson
The chemicals that are good for health seem to be acting by triggering mild adaptive stress responses in our cells that overlap quite a bit with exercise and fasting.
Dr. Mark Mattson
It's important to keep stressing in a good way, in an evolutionarily conserved way, that is, by stresses that have been normally encountered through millions of years.
Dr. Mark Mattson
If you start to lose muscle mass, then you're, you're fasting too much.
Dr. Mark Mattson
2 Protocols
Daily Time-Restricted Eating
Dr. Mark Mattson- Compress all food intake into a 6 to 8-hour time period each day.
- Fast for the remaining 16 to 18 hours, allowing for daily metabolic switching and ketone elevation.
5-2 Intermittent Fasting
Dr. Mark Mattson- Two days a week, consume only one moderate-sized meal of approximately 600 calories.
- On the other five days of the week, eat normally.