How does the body know when it's full?

The body senses fullness through mechanisms involving the stretching of the stomach wall, hormones released in response to nutrients, and neural signals to the brain.

What role does cholecystokinin play in feeling full?

Cholecystokinin is a hormone that reduces the feeling of reward from eating, slows stomach emptying, and helps signal fullness to the brain.

Why does eating slowly help you feel fuller?

Eating slowly allows time for your body to register fullness through hormone signals and stomach stretching.

How do hormones influence hunger and fullness?

Hormones like cholecystokinin and leptin send signals to the hypothalamus to moderate appetite by either reducing the sensation of reward from food or inhibiting hunger-causing neurons.

What is leptin and its function in hunger regulation?

Leptin is a hormone released by fat cells that inhibits hunger-related neurons in the hypothalamus and stimulates neurons that suppress hunger.

How do nerves contribute to the feeling of fullness?

Nerves wrapped around the stomach detect stretching and send signals via the vagus nerve to the brain to indicate fullness.

What foods are most satisfying in terms of fullness?

Foods high in protein, fiber, and water content, such as boiled potatoes, are known to produce longer-lasting fullness.

What triggers the feeling of hunger after some time of fullness?

Hormones like ghrelin are produced when the stomach is empty, increasing hunger signals in the hypothalamus.

How does your body know you're full? - Hilary Coller

00:04:33

https://www.youtube.com/watch?v=YVfyYrEmzgM

Summary

TLDRHunger and fullness are sensations managed by complex interactions between the stomach, hormones, and brain. When food fills the stomach, the stretching of its walls is detected by nerves that send signals to the brain via the vagus nerve. Additionally, the presence of nutrients triggers the release of hormones, such as cholecystokinin and leptin. These hormones interact with the hypothalamus in the brain to regulate the feelings of hunger and satiety. Cholecystokinin reduces the desire to eat by decreasing the reward feeling from food and slowing the stomach's emptying process. Meanwhile, leptin, released by fat cells, inhibits hunger-related neurons while activating those that suppress appetite. Foods high in protein, fiber, and water increase satiety and are more fulfilling than others. Despite the temporary feeling of fullness, stomach contractions and hormones like ghrelin eventually rekindle the sensation of hunger.

Takeaways

🧠 Fullness is detected by stomach stretching and nerve signals to the brain.
💡 Cholecystokinin reduces food reward feelings and slows digestion.
🐢 Eating slowly helps in recognizing fullness better.
🔄 Hormones like leptin and cholecystokinin regulate appetite.
🍽 Foods rich in protein, fiber, and water sustain fullness longer.
😩 Ghrelin and other hormones trigger hunger after some time.
📊 The hypothalamus plays a key role in managing hunger and fullness.
🏋️ Protein and fiber-rich foods prolong satiety.
🚰 Water content in food aids in filling you up.
🍞 Croissants are less satisfying than boiled potatoes.

Timeline

00:00:00 - 00:04:33
Hunger leads to a strong physical sensation that is hard to ignore. Upon eating, the sensation of fullness begins as food travels down the esophagus to the stomach, stretching it. This stretching activates nerves that communicate with the brain via the vagus nerve, alongside hormones that signal the presence of nutrients, affecting the hypothalamus to moderate appetite and induce fullness. Hormones like cholecystokinin and leptin play crucial roles in this regulation, affecting both the speed of digestion and the hunger-related neuron activity. Eventually, the body's hormonal and neural signals convey a sensation of fullness, which varies with different types of food. However, after digestion, hunger resurfaces as hormones such as ghrelin prompt a resurgence of appetite.

Mind Map

Video Q&A

How does the body know when it's full?
The body senses fullness through mechanisms involving the stretching of the stomach wall, hormones released in response to nutrients, and neural signals to the brain.
What role does cholecystokinin play in feeling full?
Cholecystokinin is a hormone that reduces the feeling of reward from eating, slows stomach emptying, and helps signal fullness to the brain.
Why does eating slowly help you feel fuller?
Eating slowly allows time for your body to register fullness through hormone signals and stomach stretching.
How do hormones influence hunger and fullness?
Hormones like cholecystokinin and leptin send signals to the hypothalamus to moderate appetite by either reducing the sensation of reward from food or inhibiting hunger-causing neurons.
What is leptin and its function in hunger regulation?
Leptin is a hormone released by fat cells that inhibits hunger-related neurons in the hypothalamus and stimulates neurons that suppress hunger.
How do nerves contribute to the feeling of fullness?
Nerves wrapped around the stomach detect stretching and send signals via the vagus nerve to the brain to indicate fullness.
What foods are most satisfying in terms of fullness?
Foods high in protein, fiber, and water content, such as boiled potatoes, are known to produce longer-lasting fullness.
What triggers the feeling of hunger after some time of fullness?
Hormones like ghrelin are produced when the stomach is empty, increasing hunger signals in the hypothalamus.

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00:00:08
Hunger claws at your grumbling belly.
00:00:10
It tugs at your intestines, which begin to writhe, aching to be fed.
00:00:15
Being hungry generates a powerful, often unpleasant physical sensation
00:00:20
that's almost impossible to ignore.
00:00:23
After you've reacted by gorging on your morning pancakes,
00:00:26
you start to experience an opposing force, fullness,
00:00:30
but how does your body actually know when you're full?
00:00:34
The sensation of fullness is set in motion as food moves from your mouth
00:00:38
down your esophagus.
00:00:41
Once it hits your stomach, it gradually fills the space.
00:00:44
That causes the surrounding muscular wall to stretch,
00:00:48
expanding slowly like a balloon.
00:00:50
A multitude of nerves wrapped intricately around the stomach wall
00:00:54
sense the stretching.
00:00:56
They communicate with the vagus nerve up to the brainstem and hypothalamus,
00:01:00
the main parts of the brain that control food intake.
00:01:04
But that's just one input your brain uses to sense fullness.
00:01:08
After all, if you fill your stomach with water,
00:01:11
you won't feel full for long.
00:01:13
Your brain also takes into account chemical messengers
00:01:16
in the form of hormones produced by endocrine cells
00:01:19
throughout your digestive system.
00:01:22
These respond to the presence of specific nutrients in your gut and bloodstream,
00:01:26
which gradually increase as you digest your food.
00:01:30
As the hormones seep out, they're swept up by the blood
00:01:33
and eventually reach the hypothalamus in the brain.
00:01:38
Over 20 gastrointestinal hormones are involved in moderating our appetites.
00:01:43
One example is cholecystokinin,
00:01:46
which is produced in response to food by cells in the upper small bowel.
00:01:51
When it reached the hypothalamus,
00:01:52
it causes a reduction in the feeling of reward you get when you eat food.
00:01:58
When that occurs, the sense of being satiated starts to sink in
00:02:02
and you stop eating.
00:02:05
Cholecystokinin also slows down the movement of food
00:02:08
from the stomach into the intestines.
00:02:11
That makes your stomach stretch more over a period of time,
00:02:15
allowing your body to register that you're filling up.
00:02:19
This seems to be why when you eat slowly, you actually feel fuller
00:02:23
compared to when you consume your food at lightning speed.
00:02:26
When you eat quickly, your body doesn't have time to recognize the state it's in.
00:02:31
Once nutrients and gastrointestinal hormones are present in the blood,
00:02:35
they trigger the pancreas to release insulin.
00:02:39
Insulin stimulates the body's fat cells to make another hormone called leptin.
00:02:44
Leptin reacts with receptors on neuron populations in the hypothalamus.
00:02:49
The hypothalamus has two sets of neurons important for our feeling of hunger.
00:02:55
One set produces the sensation of hunger by making and releasing certain proteins.
00:03:00
The other set inhibits hunger through its own set of compounds.
00:03:04
Leptin inhibits the hypothalamus neurons that drive food intake
00:03:09
and stimulates the neurons that suppress it.
00:03:12
By this point, your body has reached peak fullness.
00:03:15
Through the constant exchange of information between hormones,
00:03:18
the vagus nerve,
00:03:19
the brainstem,
00:03:21
and the different portions of hypothalamus,
00:03:23
your brain gets the signal that you've eaten enough.
00:03:27
Researchers have discovered
00:03:28
that some foods produce more long-lasting fullness than others.
00:03:32
For instance, boiled potatoes are ranked
00:03:35
as some of the most hunger-satisfying foods,
00:03:37
while croissants are particularly unsatisfying.
00:03:42
In general, foods with more protein, fiber, and water
00:03:45
tend to keep hunger at bay for longer.
00:03:49
But feeling full won't last forever.
00:03:52
After a few hours, your gut and brain begin their conversation again.
00:03:57
Your empty stomach produces other hormones, such as ghrelin,
00:04:00
that increase the activity of the hunger-causing nerve cells
00:04:03
in the hypothalamus.
00:04:05
Eventually, the growling beast of hunger is reawakened.
00:04:09
Luckily, there's a dependable antidote for that.