What causes someone to become sleepy after eating a large meal?

Answer 1

Blood can rushes to your stomache because you now have something for it to digest. You receive less blood to your brain, thus less oxygen. Soon you can become sleepy.

Also on thanksgiving its a function of triptifan a natural sedetive found in turkey. So when you eat turkey you have a double dose, triptifan and a decrease in blood to the brain

Answer 2

A "good meal" tends to be high in proteins, and, in particular, tryptophan. Tryptophan has a sedative effect, and is especially noticable in turkey.

Other factors:

Amount eaten. Large quantities cause digestion to become the major activity of the body, and consciousness loses out.

Environment. Big meals usually mean boring surroundings, and commitments to enduring company that is not your typical company (just for that reason!).

Which reminds me, I have leftover turkey in the fridge!

Answer 3

think of it this way, you got all these little energy dudes running around in your system, when you eat a large meal the dudes get to work on digesting the food, that leaves very few dudes left to sustain energy for other things so you get sleepy

Answer 4

The hydrochloric acid secreted by the lining of the stomach digests food after you've eaten. After eating, your pituitary gland secretes dopamine into your bloodstream, as a way of regenerating your body and rewarding you after tasting something nutritious.. Thats why you feel tired after eating big meals.

Answer 5

Digestion. It is hard for the body to digest a large meal and stay awake at the same time.

Peace!

Answer 6

Maybe its because more blood is being diverted for digestion and the organs involved and you become a little sleepy.

Answer 7

Its a cause and effect on the human body. To full to do any harsh work, like bending over, stretching. Need to sleep it off, buys time for body to digest!

Answer 8

The endorphins released by your body in response to the food makes you feel good and sleepy.

Answer 9

Tryptophan

Answer 10

Why we need a siesta after dinner

15:42 05 June 2006
NewScientist.com news service
Linda Geddes

The mystery of why we often feel sleepy after eating a big meal may finally have been resolved. Researchers have discovered that high blood glucose levels, similar to those after eating a big meal, can switch off the brain cells that normally keep us awake and alert.

The findings make evolutionary sense since sleepiness could be the body’s way of telling us to relax and conserve energy once we have found and eaten our food, says Denis Burdakov of the University of Manchester, UK, who led the research.

“It has been known for a while that people and animals can become sleepy and less active after a meal, but the brain signals responsible for this were poorly understood,” he says.

Burdakov’s team studied a group of brain cells called orexin neurons, which are found in the hypothalamus and produce proteins called orexins that are essential for maintaining normal wakefulness in humans. These neurons are less active at night and when they malfunction this can lead to narcolepsy, where sufferers cannot stay awake.

Firing rate...

Previously, researchers have shown that orexin neurons can be inhibited by glucose, but it was not known how sensitive they were. Burdakov’s team exposed orexin neurons to subtle changes in glucose levels similar to those that occur in the blood during daily cycles of eating and hunger, then measured their firing rate.

“What we discovered is the activity of the neurons can be turned off by minute elevations in glucose associated with normal meals,” says Burdakov. The glucose is thought to act on potassium ion channels in the neurons’ membrane.

He believes this could explain why we naturally feel sleepy after a meal and also why it can be difficult to sleep when we are hungry, since the activity of the neurons would be higher when there is less glucose in the blood.

“We think orexin neurons make sure that we are awake and alert when hungry, in order to ensure optimal food-seeking,” Burdakov says. He adds that it makes evolutionary sense for animals to turn off their wakefulness and conserve energy once they have eaten their food, since it could be risky or wasteful to expend too much energy looking for more food.

Obesity trigger...

Changes in the sensitivity of orexin neurons to glucose could lead to obesity, Burdakov speculates.

Orexin neurons are known to help regulate appetite and metabolic rate, and when they become faulty this can trigger late-onset obesity. Researchers are currently trying to understand exactly how orexin neurons interact with other brain circuits involved in appetite regulation.

“The role of orexin neurons in the control of numerous central nervous system processes makes the discovery of their ability to sense small changes in glucose potentially quite important,” says Joel Elmquist at the University of Texas Southwestern Medical Center in Dallas, US, writing in a commentary accompanying the paper in Neuron.

This is because it means a whole range of physiological processes can be regulated by the amount of fuel that is available. “Dysfunction of glucosensing may have profound effects on wakefulness and coordinated autonomic responses,” he says.

Journal reference: Neuron (vol 50, p 711)