What Tells Your Brain That You Are Full?
Your brain receives fullness signals from various sources, working together to regulate your appetite. It's not a single, simple mechanism.
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Stomach: Your stomach's distension (stretching) sends signals to your brain, indicating fullness. This is a primary, early signal. As referenced in multiple sources, your stomach tells your brain that it is full. [1, 4, 7, 8] This initial feeling usually leads you to stop eating for a few hours.
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Hormones: Several hormones play crucial roles:
- Cholecystokinin (CCK): This hormone, secreted by the gut, directly communicates with the brain to signal satiety ("I'm full"). [2, 3]
- Leptin: Produced by fat cells, leptin informs your brain about your energy stores. High leptin levels tell your brain "your fat cells are full," suppressing appetite. [9, 10]
- Ghrelin: In contrast to leptin, ghrelin is your "hunger hormone," signaling an empty stomach and stimulating appetite. It works in the short-term. [1, 9]
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Hypothalamus: This region of the brain acts as a control center, integrating signals from the stomach, hormones, and blood sugar levels to regulate appetite and energy balance. [1]
How the System Works
The process isn't just about feeling physical fullness from a distended stomach. It's a complex interplay of signals:
- You eat a meal.
- Your stomach stretches, sending nerve signals to the brain.
- Your gut releases CCK, further signaling satiety.
- Leptin levels influence long-term appetite regulation based on your body fat.
- The hypothalamus processes these signals, influencing your feeling of fullness.
The feeling of fullness is not solely based on stomach distension; hormones and the hypothalamus play vital roles in your brain's perception of satiety.
