How to Control Hunger, Eating & Satiety | Huberman Lab Essentials
This episode explains how hormones like ghrelin, insulin, and GLP-1 work together with the nervous system to regulate hunger and fullness. Dr. Huberman reveals why highly processed foods disrupt satiety signals and cause overeating. Practical tools include meal timing, food order, exercise, and yerba mate for better blood sugar control.
1. The Brain's Control Center for Hunger
Welcome to this deep dive into how our bodies regulate when we want to eat, how much we eat, and when we feel satisfied! 🧠 Dr. Andrew Huberman, professor of neurobiology at Stanford, kicks things off by emphasizing that hormones don't work alone in controlling hunger—they cooperate closely with the nervous system.
The first key brain area to understand is the hypothalamus, specifically a region called the ventromedial hypothalamus. This area has fascinated researchers for decades because it creates seemingly paradoxical effects. When scientists disrupted neurons in this region, some animals became hyperphagic (wanting to eat constantly), while others became anorexic (completely avoiding food). This tells us the ventromedial hypothalamus contains multiple populations of neurons—some promoting eating and others suppressing it.
There's another crucial player: the insular cortex, located higher up in the brain. This area processes information about what's happening inside your body (called interoception) and receives input from touch receptors in your mouth.
"Insular cortex has powerful control over whether or not you are enjoying what you're eating, whether or not you want to avoid what you're eating, whether or not you've had enough, or whether or not you want to continue eating more."
Most people think about taste receptors on the tongue, but we rarely consider the tactile essence of food—the physical sensation of chewing and the consistency of what we eat. This matters more than you might think!
2. The Famous Parabiosis Experiment
To understand how hormones influence hunger, Huberman describes a classic experiment where researchers parabiosed two rats—essentially connecting their blood supplies through surgery so they could exchange blood factors while keeping their brains and mouths completely separate.
Here's what happened: when scientists lesioned the ventromedial hypothalamus in one of the connected rats, that rat became very obese. The other rat, however, got very thin and lost weight. 🐀
What does this tell us? Since only their blood supply was linked, this proves that something in the blood—hormones or endocrine signals—is fundamentally involved in the desire to eat. This discovery opened the door to understanding the hormones that regulate feeding, hunger, and satiety.
3. Key Hormones That Regulate Appetite
The Arcuate Nucleus and MSH
One of the most exciting discoveries in appetite science over the last 20 years is the arcuate nucleus, a brain area containing fascinating neurons that release chemicals acting as either accelerators or brakes on feeding.
First, there are POMC neurons (Pro-opiomelanocortin neurons) that produce Alpha-MSH (melanocyte-stimulating hormone). This hormone is a powerful appetite suppressant:
"Alpha melanocyte stimulating hormone, MSH, reduces appetite and it's a powerful molecule."
AgRP Neurons and Ghrelin
On the flip side, AgRP neurons stimulate eating. Their activity increases dramatically when animals or people haven't eaten for a while. Meanwhile, MSH is released after we've eaten to help signal fullness.
Then there's ghrelin, a fascinating hormone released from the GI tract. Ghrelin's main role is to increase your desire to eat, and it does something really interesting:
"In addition, it creates food anticipatory signals within your nervous system, so you start thinking about the things that you happen to like to eat at that particular time of day."
Ghrelin acts like a hormonal clock! 🕐 When blood glucose drops too low, ghrelin is secreted from your gut and activates neurons in your brain. But here's the key: ghrelin also gets input from a clock in your liver connected to your hypothalamus.
Tool: Regular Meal Timing
This means if you eat at regular times each day, your ghrelin secretion will synchronize with your eating schedule. You'll start getting hungry a few minutes before your usual meal times—that's why your stomach growls at predictable times!
"If you suddenly go from eating on a very regular schedule to skipping a meal or pushing your meal timing out or shifting it at all, you're going to have ghrelin in your system and that ghrelin is going to stimulate the desire to eat."
The takeaway: Regularity of eating equals regularity of ghrelin secretion equals predictable hunger patterns.
4. Cholecystokinin (CCK) and Appetite Suppression
Another powerful hormone is CCK (cholecystokinin), which is released from the GI tract and potently reduces hunger. Its release is governed by specialized neurons detecting what's in your gut and elements of your gut's mucosal lining and microbiome.
What stimulates CCK release? Three things:
- Fatty acids (especially omega-3s and conjugated linoleic acid/CLA)
- Amino acids
- Sugar
Tool: Omega-3s and Amino Acids for Appetite Control
"Omega-3 fatty acids and conjugated linoleic acid, CLA, either from food or from supplements, stimulate the release of CCK, which then reduces or at least blunts appetite."
This is crucial to understand: when we eat, we're essentially fat foraging and amino acid foraging—even if we're not consciously aware of it.
"In other words, even if it's not conscious, we are eating until we trigger the activation of CCK."
When you get proper levels of amino acids and omega-3s (either from food or supplements), appetite stays clamped and you don't overeat. Your gut is informing your brain when you've ingested enough of what you need!
5. The Hidden Danger of Highly Processed Foods
Here's something 99.9% of people don't know about, according to Huberman: the devastating effect of emulsifiers in highly processed foods. 🚨
Emulsifiers are chemicals that combine fatty molecules with water molecules—like detergent in your laundry. Food manufacturers add them to extend shelf life, but here's the problem:
"When you ingest those foods, you're bringing those emulsifiers into your gut, and those emulsifiers strip away the mucosal lining of the gut."
Even worse, emulsifiers cause the neurons that extend into your gut to retract deeper, meaning:
- You eat processed food
- Satiety signals like CCK never get deployed
- You want to eat far more of these foods
- You've done structural damage to your gut lining
The Double Whammy
There's a parallel mechanism making things worse. Neurons in your gut sense sugar and send signals to your brain via the vagus nerve, triggering dopamine release that makes you crave more.
"So now you've got parallel signals making you want to eat more sugar, making you unaware of how much sugar you've eaten, and that are disrupting the inputs to the nervous system that signal to the rest of your brain and body that you've obtained enough fatty acids and you've obtained enough amino acids."
Tool: Choose Whole Foods
"The bottom line is that highly processed foods are just bad for you. They increase weight gain, they disrupt the lining of your gut in a way that disrupts things like CCK and proper satiety signals."
Huberman recommends checking out Dr. Robert Lustig's lecture on the history of processed foods for more information—it has millions of views and contains no conspiracy theories, just scientific facts.
6. Understanding Insulin and Blood Glucose
Insulin is essential for managing blood glucose levels. Type 1 diabetics lack insulin entirely (requiring injections), while Type 2 diabetics produce insulin but are insulin insensitive—their receptors don't respond properly.
When you eat, food breaks down into glucose. Your blood sugar needs to stay in the euglycemic range (approximately 70-100 nanograms per deciliter). Why does this matter so much?
"If glucose levels get too high, because of the way that our cells, in particular neurons, interact with glucose, high levels of glucose can damage neurons. It can actually kill them."
This is why diabetics can experience:
- Peripheral neuropathies (losing sensation in fingers, hands, or feet)
- Diabetic retinopathies (blindness)
7. Insulin, Glucagon, and Practical Tools
The Push-Pull System
Think of it this way:
- Insulin manages glucose after eating
- Glucagon pulls energy stores from liver and muscles when hungry
Once glycogen stores are depleted, you'll eventually tap into body fat for fuel.
Tool: Food Order Matters! 🍽️
Here's a fascinating finding: the order you eat each macronutrient significantly affects how quickly blood glucose rises!
If you eat rice (carbohydrate), salmon (protein), and asparagus (fiber) all mixed together, you'll get a moderately fast increase in blood glucose. But if you eat the fibrous food first:
"If you want to have a more modest increase in glucose or you want to blunt the increase in glucose, then have at least some of the fibrous thing first, and then the protein, and then the carbohydrate."
You'll notice your blood glucose rises more steadily and you'll achieve satiety earlier in the meal.
Tool: Movement and Blood Glucose
Movement has an enormous impact on blood sugar:
- Exercise before eating dampens blood glucose levels
- Even a calm, easy walk after a meal adjusts blood sugar regulation for the better
"Your blood glucose levels can be modulated very, very powerfully by movement."
8. Exercise for Stable Blood Sugar
Some people have naturally stable blood sugar (can go long periods without eating and feel fine), while others get shaky and jittery. Exercise can dramatically improve this! 💪
Zone 2 Cardio Benefits
Zone 2 cardio (steady-state exercise where you can nasal breathe and hold a conversation) for 30-60 minutes, 3-4 times per week:
"Can create positive effects on blood sugar regulation such that people can sit down and enjoy whatever it is—the hot fudge sundae or whatever the high sugar content food is—and blood glucose management is so good, your insulin sensitivity is so high, which is a good thing, that you can manage that blood glucose to the point where it doesn't really make you shaky."
High-Intensity Training Benefits
HIIT and weight training trigger mechanisms that:
- Encourage the body to shuttle glucose back into glycogen
- Restock the liver
- Cause long-standing increases in basal metabolic rate
9. Metformin and the Ketogenic Diet
Metformin
Metformin is a prescription drug developed for diabetes that dramatically lowers blood glucose. It works by:
- Changing mitochondrial action in the liver
- Operating through the AMPK pathway
- Increasing insulin sensitivity
Huberman notes he's surprised how many non-diabetics have sought out this powerful drug.
Ketogenic Diet and Blood Sugar
The ketogenic diet has been shown in 22 studies to notably decrease blood glucose—which makes sense since you're consuming very little or zero foods that spike insulin and glucose.
However, Huberman offers a caution: being in ketosis for too long can adjust thyroid hormone levels in ways that make returning to carbohydrates more difficult.
10. A Fascinating History: Diabetes Detection Through the Ages
Here's an incredible piece of medical history! 🐜 Diabetes was known about as early as 1500 BC. Ancient physicians discovered that ants would preferentially consume the urine of certain patients—those with high blood glucose.
"They understood that there was something in that urine that was correlated with the sudden weight loss and some of the other probably very unfortunate health symptoms that these people were experiencing."
Even as late as 1674, physicians at Oxford University were detecting high blood glucose by... tasting patient urine to determine which was "excessively sweet."
"For those of you that are in the medical profession or those of you that are seeking out the medical profession, do understand this is not done anymore."
Indeed, we've made remarkable progress! 😅
11. Yerba Mate and GLP-1 for Appetite Control
Huberman shares his personal tool for managing appetite: yerba mate (mate), a strong caffeinated tea. Unlike coffee, mate has unique benefits:
"Mate, also called yerba mate, is an interesting compound because unlike coffee, it has been shown to increase something called glucagon-like peptide, GLP-1, and increase leptin levels."
GLP-1 (glucagon-like peptide 1) acts as a nice appetite suppressant and helps regulate blood sugar in healthy ways—keeping it in that euglycemic "not too high, not too low" range.
Additional benefits of mate:
- Contains electrolytes (sodium, potassium, magnesium) crucial for neuron function
- Stimulates alertness like coffee
- Helps extend fasting windows
"Electrolytes are critically important for the function of the nervous system, and many things that act as diuretics that promote excretion of water, like caffeine, can also take electrolytes out along with it."
Final Thoughts
This episode covered an enormous amount of ground on how hormones regulate feeding, hunger, and satiety. The key players include:
- Ghrelin (stimulates hunger on a schedule)
- MSH (suppresses appetite)
- CCK (signals you've had enough amino acids and fatty acids)
- Insulin and glucagon (manage blood glucose)
- GLP-1 (helps regulate blood sugar and appetite)
The actionable takeaways are clear: eat at regular times to synchronize your hunger hormones, avoid highly processed foods that destroy your gut's satiety signaling, prioritize fibrous foods first in your meals, exercise regularly for stable blood sugar, and consider yerba mate as a helpful tool. As always, work with a healthcare professional to find what works best for your individual needs! 🎯
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