# Explanation for so-called sugar coma? (yawn) **URL:** \ **Category:** Factual Questions\ **Created:** [June 13, 2000, 7:59pm UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263 "2000-06-13T19:59:16Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [June 13, 2000, 7:59pm UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263/1 "2000-06-13T19:59:16Z")
I just ate a whole 7 oz. bag of Good N’ Plenty’s. Before I go upstairs to take a nap, I was wondering whether there’s a simple, 25-words-or-less layman’s explanation for why eating large amounts of sugar makes you groggy, instead of wideawake. Didn’t see anything in the thread archives concerning this, just “low blood sugar”, which I don’t think is the problem. I’ll be back later…(yawn) ---
**Author:** ![funneefarmer](https://avatars.discourse-cdn.com/v4/letter/f/9fc348/32.png) [@funneefarmer](https://boards.straightdope.com/u/funneefarmer)\ **Post date:** [June 13, 2000, 9:23pm UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263/2 "2000-06-13T21:23:11Z")
From [Sugar](http://gourmetconnection.com/diabetic/articles/797sugar.shtml) “It also calms adults, says Wurtman, who has studied the relationship between carbohydrate consumption and mood. When people report having a sugar high or jitters, Wurtman asks them what was happening before they took a mouthful of something sweet. “When people feel the need to eat,” she says, “They usually are jittery. But 20 minutes after eating, they are no longer jittery.” In fact, the opposite happens: After eating sugar, people become calm or even sleepy, she says, an effect caused by sugar raising the level of a calming brain chemical called serotonin. Sugar in its pure form is the best nonprescription antidepressant, she says.” ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [June 13, 2000, 9:25pm UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263/3 "2000-06-13T21:25:34Z")
I’ve read of two theories on this. 1. Low blood sugar (yep). Essentially, consuming sugar/other carbohydrates causes your blood sugar to spike. Your body then churns out the insulin to bring the blood sugar back down. Unfortunately, the process is never perfectly matched, and your body usually overproduces insulin, sending your blood sugar plummeting below where it was to begin with, making you feel tired (and, in some cases, hungry yet again). 2. Tryptophan. I read a brief abstract of a scientific study that suggested that tryptophan–more commonly recognized as the substance in turkey that contributes to Thanksgiving comas–is the culprit. But in this case, the tryptophan causing the drowsiness is CREATED by the body following high carb intake. I’ll see if I can dredge up the link. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [June 16, 2000, 1:51pm UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263/4 "2000-06-16T13:51:34Z")
Here’s what I was looking for. From this link, which is a pro-low-carb-diet web site. [http://www.lowcarb.org/josh\_yelon/topic7.html](http://www.lowcarb.org/josh_yelon/topic7.html) > [@](#): > > Psychobiological effects of carbohydrates. > > Spring B, Chiodo J, Harden M, Bourgeois MJ, Mason JD, Lutherer L. Department of Psychology, UHS, Chicago Medical School, IL 60064. > J Clin Psychiatry 1989 May;50 Suppl:27-33 > > The authors studied whether the fatiguing effects of eating lunch are greater for carbohydrate-rich meals than for other meals, and related the time course of behavioral change to plasma glucose, insulin, and amino acids. On different occasions, in counterbalanced order, normal women (N = 7) fasted overnight, ate a standard breakfast, and at lunch either continued to fast or ate a high-carbohydrate, low-protein meal; a hedonically similar meal containing both carbohydrate and protein; or a high-protein, low-carbohydrate meal. Meals were isocaloric and equated for fat content. Only the carbohydrate meal significantly increased fatigue, which could not be attributed to hypoglycemia because plasma glucose remained elevated. Fatigue began approximately, when the carbohydrate meal elevated the plasma tryptophan ratio but ended even though the ratio remained elevated. Fatigue after a high-carbohydrate lunch could not be explained by reactive hypoglycemia or sweet taste, and could partially be explained by the hypothesis that fatigue parallels an elevation of the tryptophan ratio. > > Comments: It’s already known that big meals loaded with carbs make you sleepy. They wanted to know why. They figured that maybe the meal would mess with your blood sugar, and when the blood sugar dropped, you’d be ``low on fuel’’, making you tired. That turned out not to be the case. Instead, when they were checking the people’s blood, they found a rise in the amount of tryptophan in the blood — tryptophan is a tranquilizer. So, in all likelihood, carb-rich meals make you tired because they create the tranquilizer tryptophan. That’s all it says. Now, I’m going to add one conclusion of my own. You can get addicted to most tranquilizers. So, it seems inevitable that you can get addicted to carbs. When addicted people are stressed out, they reach for the valium, the miltowns… and maybe the carbs? ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [June 17, 2000, 12:00am UTC](https://boards.straightdope.com/t/explanation-for-so-called-sugar-coma-yawn/22263/5 "2000-06-17T00:00:45Z")
Thank you, guys. This also explains why the 3 p.m. Snickers bar, so highly touted by Mars Candy as an afternoon pick-me-up, just makes me sleepier than ever.