cover of episode Dr. Zachary Knight: The Science of Hunger & Medications to Combat Obesity

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

2024/6/17
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Dr. Zachary Knight discusses the two systems in the brain that control hunger and satiety: a short-term system located in the brainstem that regulates meal size and a long-term system located in the hypothalamus that tracks body fat levels and adjusts hunger accordingly. He explains that leptin, a hormone produced by fat cells, acts as a signal to the brain about the body's energy reserves. When leptin levels drop due to weight loss, the brain initiates a homeostatic response that includes increased hunger, decreased energy expenditure, and other physiological changes.

Shownotes Transcript

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.

For show notes, including referenced articles and additional resources, please visit hubermanlab.com).

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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

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