Postprandial [pohst-pran-dee-uhl] somnolence [som-nuh-luhns] (colloquially known as a food coma) is a normal state of drowsiness or lassitude following a meal. It has two components: a general state of low energy related to activation of the parasympathetic nervous system (can be thought of as ‘rest and digest’ as opposed to the ‘fight-or-flight’ effects of the sympathetic nervous system) in response to mass in the gastrointestinal tract, and a specific state of sleepiness caused by hormonal and neurochemical changes related to the rate at which glucose enters the bloodstream and its downstream effects on amino acid transport in the central nervous system.
In response to the arrival of food in the stomach and small intestine, the activity of the parasympathetic nervous system increases and the activity of the sympathetic nervous system decreases. This shift in the balance of autonomic (involuntary) tone towards the parasympathetic system results in a subjective state of low energy and a desire to be at rest, the opposite of the fight-or-flight state induced by high sympathetic tone. The larger the meal, the greater the shift in autonomic tone towards the parasympathetic system, regardless of the composition of the meal.
read more »
The Daily Omnivore 