The Science of Hunger & Medications to Combat Obesity | Dr. Zachary Knight

Andrew Huberman

Jun 17, 2024

Episode description

In this episode, my guest is Dr. Zachary Knight, Ph.D., a professor of physiology at the University of California, San Francisco (UCSF), and Howard Hughes Medical Institute (HHMI) investigator. We discuss how the brain controls our sense of hunger, satiety, and thirst. He explains how dopamine levels impact our cravings and eating behavior (amount, food choices, etc) and how we develop and can change our food preferences and adjust how much we need to eat to feel satisfied.
 
We discuss factors that have led to the recent rise in obesity, such as interactions between our genes and the environment and the role of processed foods and food combinations. We also discuss the new class of medications developed for the treatment of obesity and diabetes, including the GLP-1 agonists semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro). We discuss how these medications work to promote weight loss, the source of their side effects, and the newer compounds soon to overcome some of those side effects, such as muscle loss.
 
Dr. Knight provides an exceptionally clear explanation for our sense of hunger, thirst, and food cravings that translates to practical knowledge to help listeners better understand their relationship to food, food choices, and meal size to improve their diet and overall health.

Access the full show notes, including referenced articles, books, people mentioned, and additional resources: https://www.hubermanlab.com/episode/dr-zachary-knight-the-science-of-hunger-medications-to-combat-obesity

Thank you to our sponsors
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Dr. Zachary Knight
UCSF academic profile: https://profiles.ucsf.edu/zachary.knight
HHMI profile: https://www.hhmi.org/scientists/zachary-knight
Publications: https://knightlab.ucsf.edu/publications
Lab website: https://knightlab.ucsf.edu
X: https://x.com/zaknight
Instagram: https://www.instagram.com/zknightsf
LinkedIn: https://www.linkedin.com/in/zachary-knight-29a37977

Timestamps
00:00:00 Dr. Zachary Knight
00:02:38 Sponsors: BetterHelp, Helix Sleep & Waking Up
00:07:07 Hunger & Timescales
00:11:28 Body Fat, Leptin, Hunger
00:17:51 Leptin Resistance & Obesity
00:20:52 Hunger, Food Foraging & Feeding Behaviors, AgRP Neurons
00:30:26 Sponsor: AG1
00:32:15 Body Weight & Obesity, Genes & POMC Neurons
00:39:54 Obesity, Genetics & Environmental Factors
00:46:05 Whole Foods, Ultra-Processed Foods & Palatability
00:49:32 Increasing Whole Food Consumption, Sensory Specific Satiety & Learning
00:58:55 Calories vs. Macronutrients, Protein & Salt
01:02:23 Sponsor: LMNT
01:03:58 Challenges of Weight Loss: Hunger & Energy Expenditure
01:09:50 GLP-1 Drug Development, Semaglutide, Ozempic, Wegovy
01:19:03 GLP-1 Drugs: Muscle Loss, Appetite Reduction, Nausea
01:23:24 Pharmacologic & Physiologic Effects; GLP-1 Drugs, Additional Positive Effects
01:30:14 GLP-1-Plus Development, Tirzepatide, Mounjaro, AMG 133
01:34:49 Alpha-MSH & Pharmacology
01:40:41 Dopamine, Eating & Context
01:46:01 Dopamine & Learning, Water Content & Food
01:53:23 Salt, Water & Thirst
02:03:27 Hunger vs. Thirst
02:05:46 Dieting, Nutrition & Mindset
02:09:39 Tools: Improving Diet & Limiting Food Intake
02:14:15 Anti-Obesity Drug Development
02:17:03 Zero-Cost Support, Spotify & Apple Follow & Reviews, YouTube Feedback, Social Media, Neural Network Newsletter

#HubermanLab #Health #Obesity

Title Card Photo Credit: Mike Blabac - https://www.blabacphoto.com

Disclaimer: https://www.hubermanlab.com/disclaimer

Episode description

In this episode, my guest is Dr. Zachary Knight, Ph.D., a professor of physiology at the University of California, San Francisco (UCSF), and Howard Hughes Medical Institute (HHMI) investigator. We discuss how the brain controls our sense of hunger, satiety, and thirst. He explains how dopamine levels impact our cravings and eating behavior (amount, food choices, etc) and how we develop and can change our food preferences and adjust how much we need to eat to feel satisfied.
 
We discuss factors that have led to the recent rise in obesity, such as interactions between our genes and the environment and the role of processed foods and food combinations. We also discuss the new class of medications developed for the treatment of obesity and diabetes, including the GLP-1 agonists semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro). We discuss how these medications work to promote weight loss, the source of their side effects, and the newer compounds soon to overcome some of those side effects, such as muscle loss.
 
Dr. Knight provides an exceptionally clear explanation for our sense of hunger, thirst, and food cravings that translates to practical knowledge to help listeners better understand their relationship to food, food choices, and meal size to improve their diet and overall health.

Access the full show notes, including referenced articles, books, people mentioned, and additional resources: https://www.hubermanlab.com/episode/dr-zachary-knight-the-science-of-hunger-medications-to-combat-obesity

Thank you to our sponsors
AG1: https://drinkag1.com/huberman
BetterHelp: https://betterhelp.com/huberman
Eight Sleep: https://eightsleep.com/huberman
Waking Up: https://wakingup.com/huberman
LMNT: https://drinklmnt.com/huberman

Huberman Lab Social & Website
Instagram: https://www.instagram.com/hubermanlab
Threads: https://www.threads.net/@hubermanlab
Twitter: https://twitter.com/hubermanlab
Facebook: https://www.facebook.com/hubermanlab
TikTok: https://www.tiktok.com/@hubermanlab
LinkedIn: https://www.linkedin.com/in/andrew-huberman
Website: https://www.hubermanlab.com
Newsletter: https://www.hubermanlab.com/newsletter

Dr. Zachary Knight
UCSF academic profile: https://profiles.ucsf.edu/zachary.knight
HHMI profile: https://www.hhmi.org/scientists/zachary-knight
Publications: https://knightlab.ucsf.edu/publications
Lab website: https://knightlab.ucsf.edu
X: https://x.com/zaknight
Instagram: https://www.instagram.com/zknightsf
LinkedIn: https://www.linkedin.com/in/zachary-knight-29a37977

Timestamps
00:00:00 Dr. Zachary Knight
00:02:38 Sponsors: BetterHelp, Helix Sleep & Waking Up
00:07:07 Hunger & Timescales
00:11:28 Body Fat, Leptin, Hunger
00:17:51 Leptin Resistance & Obesity
00:20:52 Hunger, Food Foraging & Feeding Behaviors, AgRP Neurons
00:30:26 Sponsor: AG1
00:32:15 Body Weight & Obesity, Genes & POMC Neurons
00:39:54 Obesity, Genetics & Environmental Factors
00:46:05 Whole Foods, Ultra-Processed Foods & Palatability
00:49:32 Increasing Whole Food Consumption, Sensory Specific Satiety & Learning
00:58:55 Calories vs. Macronutrients, Protein & Salt
01:02:23 Sponsor: LMNT
01:03:58 Challenges of Weight Loss: Hunger & Energy Expenditure
01:09:50 GLP-1 Drug Development, Semaglutide, Ozempic, Wegovy
01:19:03 GLP-1 Drugs: Muscle Loss, Appetite Reduction, Nausea
01:23:24 Pharmacologic & Physiologic Effects; GLP-1 Drugs, Additional Positive Effects
01:30:14 GLP-1-Plus Development, Tirzepatide, Mounjaro, AMG 133
01:34:49 Alpha-MSH & Pharmacology
01:40:41 Dopamine, Eating & Context
01:46:01 Dopamine & Learning, Water Content & Food
01:53:23 Salt, Water & Thirst
02:03:27 Hunger vs. Thirst
02:05:46 Dieting, Nutrition & Mindset
02:09:39 Tools: Improving Diet & Limiting Food Intake
02:14:15 Anti-Obesity Drug Development
02:17:03 Zero-Cost Support, Spotify & Apple Follow & Reviews, YouTube Feedback, Social Media, Neural Network Newsletter

#HubermanLab #Health #Obesity

Title Card Photo Credit: Mike Blabac - https://www.blabacphoto.com

Disclaimer: https://www.hubermanlab.com/disclaimer

Mindsip insights from this episode:

Acknowledge genetics' role in body weight determination

The heritability of body weight is estimated to be around 80%, meaning genetics, more than most diseases, determines where an individual lies on the body weight distribution.

Address environmental factors to combat obesity crisis

The modern obesity crisis is explained by the environment 'pulling the trigger' on genetic predispositions, shifting the entire population's weight distribution higher.

Understand hunger neurons as calorie counters for better dietary choices

The brain's primary hunger neurons (AGRP) are mainly 'calorie counters' and are inhibited equally by fat, protein, or sugar, as long as the calorie count is the same.

Address hunger challenge after weight loss to maintain results

After weight loss, for every two pounds lost, hunger increases by about 100 calories per day, a much stronger effect than the 30-calorie drop in metabolism.

Understand limitations of natural GLP-1 boosts for weight loss

Boosting the body's natural GLP-1 levels threefold does not cause weight loss, explaining why only pharmacological drugs like Ozempic, which create thousand-fold increases, are effective.

Utilize next-gen weight-loss drugs to minimize nausea and enhance effectiveness

Next-generation weight-loss drugs like Mounjaro (Tirzepatide) combine GLP-1 with a GIP agonist, which is thought to reduce nausea and allow for higher, more effective doses.

Differentiate hunger as reward and thirst as pain

Hunger and thirst are driven by different motivations; hunger makes food more rewarding, while thirst is a deeply unpleasant state that the brain seeks to eliminate.

Understand leptin resistance to address obesity effectively

Leptin failed as a blockbuster diet drug because most obese individuals are not deficient in leptin but are actually leptin-resistant, similar to insulin resistance.

Leverage hunger neurons to predict meal size instantly

Specialized hunger neurons (AGRP neurons) can predict the caloric content of an upcoming meal and decrease their activity within seconds of seeing food, even before the first bite is taken.

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