Protocols
Source
We recommend using this distillation as a supplemental resource to the source material.
Full Notes
Sugar and the Nervous System
- Sugar is not inherently bad, but consuming a lot of refined sugars, especially high fructose corn syrup, can have negative effects on the brain and body
- Calories in, calories out principle: if we ingest more energy than we burn, we gain weight; if we ingest less energy than we burn, we lose weight; if the two are balanced, we maintain weight
- Sugar impacts the brain in ways that make us crave more sugar and affect our focus, agitation, happiness, and depression
- The nervous system regulates many functions and behaviors related to sugar, such as thinking, exercising, gaining/losing weight, and achieving goals
What Happens When We Eat Sugar
- When we ingest sugar, two mechanisms make us crave more sugar
- Ingesting sugar affects neural circuits, impacting focus, agitation, happiness, and depression
- Sugar plays a critical role in achieving goals, but ingesting too much or the wrong forms can impede progress
- The brain responds to sugar intake by regulating various functions and behaviors
Hormonal Response to Ingesting Food - Ghrelin: hormone that increases depending on how long it’s been since we ate last
- Makes us hungry by interacting with neurons in the arcuate nucleus of the hypothalamus and lateral hypothalamus
- Ghrelin levels go down when we eat
- Blood glucose (blood sugar) rises when we eat, especially when consuming carbohydrates
- Insulin, released from the pancreas, helps regulate blood glucose levels
- Diabetics (type 1) need to take insulin when they eat to avoid neurotoxicity and other negative effects of high blood sugar
- Neurons in the brain and body use glucose to function, allowing them to fire electrical potentials and communicate with other neurons
Study on Glucose and Brain Function
- Study published in the journal Neuron
- Examined orientation-tuned neurons in the visual cortex, which respond to specific angles of lines and are the building blocks for visual perception
- Found that the sharpness and precision of orientation tuning of these neurons is dependent on blood glucose levels
- Neurons functioned best when subjects were fed and glucose was available
- In fasted states, the orientation tuning of neurons became broader, leading to distorted and blurred perception of the outside world
Intermittent Fasting and Focus
- Some people, including the speaker, find that they are more focused during fasted states
- Intermittent fasting involves eating within a specific time window, such as between 11:00 a.m. and 8:00 p.m., and fasting outside of that window
- The speaker suggests that the increased focus during fasted states may be related to the changes in neuronal function observed in the study
Fasting, Glucose, and Brain Function - Fasting can lead to mental clarity
- Neurons use available fuels (glycogen, fat, blood sugar) from previous food intake
- Neurons love glucose
- Properly elevated blood glucose levels allow neurons to work best
- Astrocytes deliver glucose to neurons
- Most abundant cell type in the brain
- Involved in shaping neuronal function and brain plasticity
Fructose vs. Glucose
- Fructose found in fruit and high fructose corn syrup
- Fruit has lower concentrations of fructose compared to high fructose corn syrup
- Fructose cannot directly access the brain
- Needs to be converted into glucose in the liver
- Fructose reduces hormones that suppress ghrelin (hunger hormone)
- Increases ghrelin levels, making us hungrier
- Eating fruit in moderation does not lead to overeating or weight gain
- High fructose corn syrup and excessive fructose consumption can negatively impact brain function and appetite regulation
Fructose and Hunger
- High fructose corn syrup and excessive fructose consumption can negatively impact brain function and appetite regulation
- Fructose can suppress pathways that suppress hunger, leading to increased hunger
- Current recommendations encourage eating more fruits and vegetables
- High fructose corn syrup is not recommended due to its high fructose content
- Some people find that fruit can stimulate their appetite
Sugar and Attraction
- Sugar is attractive due to its taste and its ability to raise blood glucose levels
- Two parallel pathways in the brain control sugar consumption:
- One pathway is related to the perception of sweet taste
- The other pathway is related to the nutritive component of sweet foods (raising blood glucose)
- These pathways are separate from those controlling the desire for savory, salty, or spicy foods
Sweet Taste Perception
- Sweet taste receptors are found on the tongue and palate
- Ingesting something sweet sends signals to the brain, causing a shift in perception of food
- This shift makes sugary foods and other foods appear more appetizing
- Dopamine, a neuromodulator, is involved in motivation and craving for sweet foods
Nucleus of the Solitary Tract and Sugar Preference - The nucleus of the solitary tract is crucial for understanding sugar preference
- Neuropod cells trigger activation of dopamine pathways within the mesolimbic reward pathway
- Signals are conveyed from the gut to the brain when we ingest sweet foods
- Not related to the perception of sweetness, but the correlation with increased blood glucose
- This leads to a preference for sweet foods and a desire to eat more
Hidden Sugars and Neuropod Cells
- Hidden sugars are often masked with salt or other flavors to increase consumption
- Savory foods can contain hidden sugars that trigger neuropod cells and increase dopamine, leading to cravings for more food
Three-pronged Push for Sugar Consumption
- Sweet taste of sugary foods
- Signals from the gut to the brain (neuropod cells)
- Metabolic consequences of sugary foods
- The nervous system is a glucose-consuming machine, with at least three pathways pushing us to seek and consume more sugar
Glycemic Index and Sugar Intake Control
- Glycemic index measures how quickly blood sugar rises after ingesting particular foods
- Low glycemic index: <55
- Medium glycemic index: 55–69
- High glycemic index: >70
- Ingesting fiber and/or fat along with food can reduce the glycemic index
- The context in which food is ingested also matters (e.g., after hard training, high glycemic foods like mangoes can be beneficial)
Glycemic Index and Dopamine Release - Neurons prefer glucose for energy
- Sweet things trigger dopamine release and make us want to eat more
- Sharp rise in blood glucose = more potent dopamine signal
- To reduce sugar cravings, consider:
- Consuming sweet foods with lower glycemic index
- Combining sweet foods with fiber or fat to reduce glycemic index and slow dopamine release
Conditioned Taste Preference
- New area of nutrition neuroscience
- Studies show that pairing a flavor with maltodextrin (which increases blood glucose) can lead to the flavor alone increasing insulin levels
- Controversial findings with artificial sweeteners
- Some studies suggest that artificial sweeteners can also increase insulin levels when paired with maltodextrin
- More research needed, especially on plant-based non-caloric sweeteners
Reducing Refined Sugars and High Fructose Corn Syrup
- Most people should reduce intake of refined sugars and high fructose corn syrup
- Dr. Robert Lustig’s work highlights the dangers of hidden sugars in processed foods
- Reducing sugary drinks and fruit juices with added sugar is important for overall health
- Emerging research suggests that reducing sweet foods and refined sugars may have additional benefits for healthy individuals
Artificial Sweeteners and Insulin - Artificial sweeteners may increase insulin even in the absence of food
- Example: Diet soda alone could increase insulin without increasing blood glucose
- Controversial data due to unusual experimental conditions
- Studies on artificial sweeteners’ impact on gut microbiome mainly done on animals
- Disruption to gut microbiome can affect immune health and brain health
Conditioned Flavor Preference
- Ingesting sweet foods can lead to wanting more sweet foods
- Also increases desire for glucose-elevating foods and food in general
- Useful to understand for those struggling with regulating appetite and sugar cravings
ADHD and Sugar Consumption
- Refined sugar consumption is not good for people with ADHD or attentional issues
- However, consuming no glucose is also not ideal
- Meta-analysis shows negative outcomes for ADHD symptoms when consuming more than four 12-ounce sugary drinks per week
- Controversy over whether sugar consumption can cause ADHD
- Omega‑3 fatty acid supplementation can be beneficial for children with ADHD
- Can also improve mood and cardiovascular health
Neuropod Cells
- Neuropod cells in the gut detect levels of sugar, amino acids, and essential fatty acids
- Communicate this information to the brain through electrical potentials
- Generic language, not specific to each nutrient type
Adjusting Blood Glucose Levels
- Lemon juice and lime juice can blunt blood glucose spikes
- Possibly due to post-ingestive effects of glucose in the gut
- Sour taste on the tongue can change neural response to sweet foods
- Cinnamon can help control blood sugar
- Adjusts the rate of glucose entry into the bloodstream
- May slow gastric emptying time
- Limit to 1–1.5 teaspoons per day due to cumidin content
- Berberine is a potent substance for reducing blood glucose
- On par with prescription drugs like metformin
- Can cause hypoglycemia if taken on an empty stomach or with low carbohydrate intake
- Typical dosage range: 0.5–1.5 grams daily
- Sodium caprate can augment the effects of berberine
- Maintaining low to moderate blood glucose can lead to long-standing changes in neural circuits
- May result in reduced sugar cravings over time
Note: Always consult with a medical professional before using potent substances like berberine or metformin to control blood glucose levels.
Controlling Sugar Cravings and Neural Circuits
- Berberine: potent substance for controlling sugar cravings
- Sleep: high-performance tool for controlling sugar cravings and neural circuits
Role of Sleep in Sugar Metabolism and Hunger
- Study published in Cell Report
- Measured metabolites from people’s breath during sleep
- Evaluated metabolism in the brain and body during different sleep phases
- Each sleep stage associated with a specific pattern of metabolism
- Particular phases of sleep linked to sugar metabolism, fat metabolism, etc.
- Disrupted sleep can increase appetite for sugary foods
- Poor sleep quality may disrupt metabolic pathways
Importance of Sleep for Metabolism
- Quality sleep helps regulate appetite and specific forms of metabolism
- Proper sleep essential for immune system function, clear thinking, and regulating sugar metabolism
- Aim for regular, sufficient, high-quality sleep at least 80% of the time
Support the Podcast
Huberman Lab Premium Subscription
- $10/month
- 1 Ask Me Anything (AMA) episode per month
- Significant contribution to fund human scientific research selected by Dr. Huberman (with dollar-for-dollar matching from the Tiny Foundation)
- Early-access to Huberman Lab live events
- Subscribe here
Huberman Lab Neural Network Newsletter
- Zero-cost newsletter with summaries of podcast episodes and protocolsToolkits for sleep, focus, neuroplasticity, cold/heat exposure, fitness, and flexibility
- Sign up at hubermanlab.com (email not shared)
- Downloadable PDFs of previous newsletters available without sign-up
Huberman Lab Social Media
Sponsors
Levels Continuous Glucose Monitor
- Helps assess the impact of food, food combinations, and timing on blood glucose
- Provides real-time feedback on diet and blood sugar
- levelshealth.com/huberman
Inside Tracker
- Personalized nutrition platform that analyzes blood and DNA data
- Provides personalized dashboard with nutrition, behavior, and supplement recommendations
- Now includes apolipoprotein B (APOB) measurement in their ultimate plan
- Visit insidetracker.com/huberman for 20% off any plan
Momentous
- High-quality supplements used by sports teams and in Department of Defense studies
- Single ingredient formulations
- livemomentous.com/Huberman
LMNT
- Sciencebacked ratio of electrolytes: 1 gram of sodium, 200 milligrams of potassium, and 60 milligrams of magnesium and no sugar.
- drinklmnt.com/huberman for free sample pack
Whoop
- Fitness wearable device that tracks daily activity and sleep
- Provides real-time feedback on optimizing health
- Visit join.whoop.com/Huberman for the first month free
Roka
- Eyeglasses and sunglasses designed for athletes and everyday people
- Visit roka.com and enter code Huberman for 20% off the first order
Helix Sleep
- Customized mattresses and pillows for better sleep
- Visit Helixsleep.com/Huberman for up to $350 off and two free pillow