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Judith J. Wurtman, PhD

Judith J. Wurtman, PhD

Posted: February 16, 2011 08:15 AM

Dropping Serotonin Levels: Why You Crave Carbs Late in the Day


You may think you are the only mom who seems to go a little crazy around four or five p.m. when it is getting dark and it's too cold or icy to go outside and your kids are getting cranky or worse. Join the club of moms who find their sanity slipping a wee bit late every afternoon and resort to the only therapeutic agent they can find: sweet or starchy snacks.

Recently, a freelance writer who works from home while taking care of an infant and toddler told me that she dreads the interval between four and six p.m. " I find myself becoming cranky and impatient and I certainly can't concentrate enough to write even if the kids don't need me for a few minutes," she said. "But what is really dreadful is that all I want to do is eat. I feed the kids around five and plan to wait until my husband comes home later to eat my dinner. What happens instead is that I start to snack while the kids are eating and then polish off their leftovers. I am always eating some cold potatoes, gummy macaroni or soggy crackers. Two hours later I eat a regular supper."

There is something about the late afternoon that changes many moms from rational, in control, effective, energetic people into grumpy, irritable and exhausted beings who want to do nothing more than lie on a couch and watch Dr. Phil. And when two kids with an ever-increasing noise level and the Golden Retriever (and the fur he shed yesterday) occupy the couch, you may find yourself going to the kitchen and stuffing yourself with any sweet or starchy snack you can find. It seems a perfectly natural response and one that prevents you from banging your head against the wall.

But consider this. This same stress, kids, dog, and dog fur that sends you chasing after a snack most likely would not have the same affect on you earlier in the day. The "perfect stress storm" that wipes away your control over eating is a combination of time of day and changes in brain serotonin.

Serotonin, "the keeping you in a sane mood" brain chemical, seems to become less active late in the afternoon. This drop in activity is not restricted to mothers with children under 10 and a shedding dog or, for that matter, only to women. Many people experience a decline in their mood late in the afternoon and with it, a need to snack on a sweet or starchy food. The combination of a mood and appetite change is a signal that serotonin activity may be dropping.

No one has ever directly measured this alteration in serotonin activity; doing so would require seriously invasive procedures. But most human research involving serotonin with behavioral measurements can tell us whether there is a change going on in the brain. Some signs of decreased serotonin include grumpiness, irritability, impatience, fatigue, inability to focus, depression and anger. Often these mood changes are accompanied by a craving for carbohydrates.

We discovered this decades ago while carrying out a study at MIT with volunteers who snacked regularly on carbohydrates in the afternoon. Many of them mentioned a predictable change in their mood starting around three-thirty or four p.m. and lasting until five or five-thirty. A salesman told us that he never made cold calls in the late afternoon because he could not tolerate people hanging up on him. This didn't bother him earlier in the day. A competitive bridge player mentioned that time of day as a bad one for focus, and a medical epidemiologist said that she couldn't concentrate on her reports at that time of day. All of them would automatically stop what they were doing to eat a carbohydrate snack like graham crackers or pretzels or popcorn. 20 to 30 minutes later, they were able to resume what they had been doing.

Why does change in mood happen? And why does eating carbohydrate make a difference Eating any carbohydrate (except that in fruit) increases the brain's production of serotonin. So if low or less than fully active serotonin makes moms or anyone else feel grumpy, tired and depressed, eating a small amount of carbohydrate replaces those moods with better ones and does so naturally.

We tested this by measuring the moods of afternoon snackers after they consumed a drink containing carbohydrate or protein. (Protein prevents serotonin from being made.) No improvement in mood was found after they had the protein drink. If they were grumpy before, they were grumpy afterward. But the carbohydrate drink really picked up their mood. They were less depressed, angry, irritable and tired. It is not known why the late afternoon seems to affect serotonin and mood. Is it loss of sunlight? Perhaps, but many people crave carbohydrates at four p.m. in July or August when it is bright and sunny outside.

It is known that women's brains have less serotonin than those of men. Does this mean they are more likely to reach for a snack in the afternoon? No one has ever done a study on what daddies snack on in the late afternoon when they are stuck in the house for hours with yelling kids and a barking dog.

Fortunately for everyone, serotonin mood relief does not require eating much carbohydrate. As long as the snack contains about 30 grams of sugar or starchy carbohydrate, no more than one to two grams of fat (fat slows down digestion and adds unneeded calories) and the same small amount of protein, serotonin can be produced within 20 to 30 minutes. Breakfast cereal eaten dry can make a great snack. Share it with your kids. Their mood will get better as well. (But the dog will continue to shed.)

 

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You may think you are the only mom who seems to go a little crazy around four or five p.m. when it is getting dark and it's too cold or icy to go outside and your kids are getting cranky or worse. Joi...
You may think you are the only mom who seems to go a little crazy around four or five p.m. when it is getting dark and it's too cold or icy to go outside and your kids are getting cranky or worse. Joi...
 
 
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12:21 PM on 02/17/2011
I really have to say that I am quite worried by any article that suggests eating sugary breakfast cereals is a good idea.

I've had very good success with energy levels and controlling cravings by watching my protein levels and making sure I don't eat some overly high carb breakfast.

I'd disagree with the doctor on this one and suggest that maybe try eating a couple of eggs for breakfast and that will help you avoid this crashing and burning later in the day. (The new reports suggest eggs aren't the evil little demons we have been warned of for years.)
11:58 AM on 02/17/2011
Tea Time!

My local tea shop taught me the following. A tsp. of tea is good for three cups: the first is the "brew" and the next two are "infusions". Tea has caffeine and serotonin. Caffeine is highly soluble in water, so the first cup has most of the caffeine. The next two have proportionally more serotonin.
So, if you have your tea in the afternoon when you're feeling a little tired, the first cup is a good pick-me-up and the next two are a great way to calm down.
Your article reinforces the rumor that drinking tea is good for the waistline. Drinking tea is a great antidote to the afternoon carbo cravings. Try it! If I'm wrong, I'd love to hear why.
10:22 AM on 02/17/2011
How do you know those symptoms aren't just from doing it all day? You're on the phone with customers all day. Obviously the later part of the day is when you'll start to lose your cheery attitude.
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HUFFPOST SUPER USER
purenergy
03:46 AM on 02/17/2011
Wow, I have a really hard time accepting your advice to eat more sugary snacks, (but not fruit?). Maybe some veggies or a baked potato, but sugary snack? How does protein (which is what serotonin is made from) block its production? That doesn't seem logical. I realize that the metabolizing of carbohydrates allows for more free passage of serotonin through the blood brain barrier, but "blocks its production"? Could you explain that please.
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TheBaffler
a long the riverrun
01:56 AM on 02/17/2011
Carbs are far healthier for you than the Atkins diet is.
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07:49 AM on 02/17/2011
What a good little ornischobot you are... but of course, you have no peer reviewed study to submit.
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TheBaffler
a long the riverrun
10:16 AM on 02/17/2011
Oh, really? C. Everett Koop and American Medical Association's Council on Food and Nutrition aren't experts enough for you?

'The Chair of Harvard's nutrition department went on record before a 1973 U.S. Senate Select Committee investigating fad diets: "The Atkins Diet is nonsense... Any book that recommends unlimited amounts of meat, butter, and eggs, as this one does, in my opinion is dangerous. The author who makes the suggestion is guilty of malpractice."[4]

'The Chair of the American Medical Association's Council on Food and Nutrition testified before the Senate Subcommittee as to why the AMA felt they had to formally publish an official condemnation of the Atkins Diet: "A careful scientific appraisal was carried out by several council and staff members, aided by outside consultants. It became apparent that the [Atkins] diet as recommended poses a serious threat to health."[5]

'The warnings from medical authorities continue to this day. "People need to wake up to the reality," former U.S. Surgeon General C. Everett Koop writes, that the Atkins Diet is "unhealthy and can be dangerous."[6]'

http://www.atkinsexposed.org/

There's far, far more expert condemnation of Atkins than is quoted above.
12:26 AM on 02/17/2011
Some people responsibly made a choice not to breed and still get cranky and grumpy around 4-6.
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DrP
11:22 PM on 02/16/2011
Why do you crave carbohydrates later in the day?
Because you ate them earlier in the day.
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11:03 PM on 02/16/2011
I stopped eating almost all carbs except vegetables and, guess what, NO CRAVINGS ANYMORE.
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DrP
11:23 PM on 02/16/2011
Amen.
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TheBaffler
a long the riverrun
01:54 AM on 02/17/2011
If you're on the Atkins diet, you now have more serious problems than craving carbs.
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10:53 AM on 02/17/2011
Well, no, I'm not on any particular program, but I completely disagree with your assessment.
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ChaCubed
Republicans: the Antichrist
10:37 PM on 02/16/2011
Peamit butter on an apple works wonders for me; both when I am craving carbs, and when I have that I'm-hungry-but-I-know-nothing-will-make-me-feel-full feeling that causes prowling and pacing throughout the kitchen and pantry. It's really amazing.
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ChaCubed
Republicans: the Antichrist
11:35 PM on 02/16/2011
Peamit butter?

Note to self: Do not type while lying down.

:)
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Lorraine Roe
Author, Ducati rider, intuitive, wife, mom
09:18 PM on 02/16/2011
That explains a lot, she said while eating chocolate in the late afternoon.
08:52 PM on 02/16/2011
Now I know!
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NyJimbo
You wanna go that way? Oh, we'll go that way !
07:59 PM on 02/16/2011
Actually I crave alcohol in the late afternoon. This article has nothing for me............
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ChaCubed
Republicans: the Antichrist
10:29 PM on 02/16/2011
Good joke, enjoyed it, but alcohol is a carb.
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07:54 PM on 02/16/2011
Wow thanks! I just thought it was 'cause they're yummy!
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situationcritical
SuperMegaUltraUberLiberal
07:54 PM on 02/16/2011
Great article. I have been trying to pinpoint reasons for my cravings in the late afternoon for years. It's no big deal - manageable, but also good to know there's a study behind it.
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katmeyster
Proud practical progressive atheist
06:56 PM on 02/16/2011
Just stop eating carbs if you are craving them. Those of us on a carb-restricted diet have lost our cravings for sugar and carbohydrates. We have lost weight, lowered our cholesterol, lowered our blood pressure, and are no longer pre-diabetic. Just stop eating the carbs -- there is 80 years of science behind carb restriction and you can read Gary Taubes Good Calories, Bad Calories to follow the science. When I get hungry, I eat -- real food, not the processed cr*p that just makes you hungrier for more.
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iRock
and that's all that needs to be said...
08:05 PM on 02/16/2011
i love green smoothies in the morning. i usually have peanuts or a banana around when im hungry though. good advice from you.

real food rocks.
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Lorraine Roe
Author, Ducati rider, intuitive, wife, mom
09:18 PM on 02/16/2011
Trying, trying.