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How does stomach and digestive tract fullness help stop food intake?

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Two wild horses graze on tall grass in the open prairie of Theodore Roosevelt National Park, with rolling badlands visible in the background. — Feeding behaviour Wild horses graze in the Badlands of North Dakota.

In the context of feeding behavior, the fullness of the stomach and digestive tract plays a critical role in signaling the body to stop eating through several physiological mechanisms:

Distension Receptors: The digestive tract contains specialized receptors that monitor its volume. When food fills the stomach and intestines, these distension receptors are activated, sending signals to the brain that contribute to the sensation of fullness, or satiety.12
Hormonal Signaling: The presence of food in the stomach and small intestine triggers the release of hormones such as cholecystokinin. This hormone may induce satiety by activating the satiety center in the hypothalamus or by inhibiting the emptying of the stomach, which prolongs the feeling of distension.3
Neural Pathways: Sensory information regarding the state of internal organs is transmitted to the brain via the vagus nerve, which is a key component of the parasympathetic nervous system.4

These signals converge on brain mechanisms to lower feeding motivation. When the accumulation of these satiety signals overrides the positive stimuli of food, hunger drops below a critical level, and food intake ceases.1