What causes a carb coma?

Brandi M.
on 3/17/10 12:53 am - Baltimore, MD
I don't eat generally eat empty carbs, but I had a handful and half of pretzels at work last night and about 20 minutes after eating them, I was literally nodding off. I'm assuming this is what is referred to as the carb coma. What causes that???

on 3/17/10 12:59 am

"Carb coma" is caused by blood sugar spikes, which then lead the body to producing an excess of insulin. Once the insulin causes the uptake of all the sugar, there is still some left and it causes the blood sugar to dip even lower....causing you to be drowsy, want to lie down, sometimes even shakiness from the need to refuel.

It usually occurs in response to carbohydrates that are refined moreso than with carbohydrates that are non-refined (like whole grains, veggies, etc.).

Pretzels are refined carbs and therefore more likely to cause that response.

If you eat carbs with other foods it will slow their uptake into the bloodstream and decrease the likelihood of that happening.


Marilyn (now in NM)
RNY 10/2/01
(updated March 2012)

Brandi M.
on 3/17/10 1:05 am - Baltimore, MD
Thanks for the info. I was pretty sure that's what it was. Now I know not to eat pretzels at work anymore!
H.A.L.A B.
on 3/17/10 1:26 am, edited 6/10/21 12:15 am

It is mostly caused by carbs - due to insulin release - but it may or may not be caused by low blood sugar - it is mostly caused by chemicals released into the brain.

What Makes You Feel Tired after Eating?

What makes you feel tired after eating? It is actually a process that takes place in your body and results into the condition. Feeling tired after eating is usual when you consume food stuffs that have large volumes of sugar and flour in them such as bakery or sweet food items. Presence of excess sugar in your body results into increase in the blood sugar level. This further leads the pancreas to produce more insulin and release it into the blood stream of your body. Excess secretion of insulin, results into a substance called tryptophan to move into the brain. Tryptophan is a protein building block and which on reaching the brain gets transformed into serotonin. It is finally due to serotonin, that you feel tired after eating.

Hala. RNY 5/14/2008; Happy At Goal =HAG

"I can eat or do anything I want to - as long as I am willing to deal with the consequences"

"Failure is not falling down, It is not getting up once you fell... So pick yourself up, dust yourself off, and start all over again...."

on 6/9/21 2:46 pm
RNY on 03/23/17

What do you do to avoid?

Limit portions at a sitting?

Still struggling with crashing / coma.

H.A.L.A B.
on 6/10/21 7:33 am

What do I do?

  1. Avoid some foods. Or eat only small qty, together with proteins and fats.
  2. Limit portions I eat, eating slowly so I know when to stop. (That is still a challenging to me at times)
  3. Keep a detailed journal: what you eat, how much, what time, and how that makes you feel.

Based on the 3rd you can identify patterns. There are foods that I get "food coma" when I ate more than 1/2 (flat) Tbsp, even when I ate that together with fats and proteins (i.e. mashed potatoes).

The first 2 would also allow you to maintain your new slim(er) figure.

Eating too much, and too fast - I almost always end up in food coma. Slider foods (carbs), shakes, soups, are my kryptonite.
Once you figure out what and how much food is casing the issue, you may have to repeat the steps when they stopped working. A few years after the WLS I developed allergies to dairy proteins, mostly whey. Drinking milk based protein drinks, cottage cheese, cream cheese, yogurt - that almost always caused food coma when I had "a fair" portion. That was beside foods allergy symptoms. I don't get food coma with aged (hard) cheese, but I still get some symptoms of allergies.

To add: I have SIBO (google for more info); that's bacteria in small intestine. They are neither "bad" or "good" bacteria, but bacteria that not supposed to be in my small intestine, but only (mostly) in the colon. That bacteria can and "learn" to process some fiber and cause symptoms of higher sugar intake. (they can ferment the fiber into sugars, gas, etc.). The more of one time of food (with fiber) I eat, the more the bacteria in my small intestine can get specialize "to digest" that.
Not following "mono diet" is critical for me. I learned to change what I eat, rotate foods during the day and the week.

Hala. RNY 5/14/2008; Happy At Goal =HAG

"I can eat or do anything I want to - as long as I am willing to deal with the consequences"

"Failure is not falling down, It is not getting up once you fell... So pick yourself up, dust yourself off, and start all over again...."

on 6/10/21 5:33 pm
RNY on 03/23/17

I relate to do much of this.

I keep telling my family food is my kryptonite.

I don't have it figured out.

Another thing is I am staying almost protein only and my body is producing a tremendous amount of stool.

I always feel better when it comes out.

But seems like what comes out is about same volume as what I'm eating.

It's shocking.

Sheryl W.
on 3/17/10 3:13 am - Kingston, Canada
RNY on 06/24/08 with
Wow, this post sure has helped me with a couple of concerns I have had lately.  I am almost 2 yrs post-op, and having trouble with dizziness, feeling of shaky.  Usually after eating.  I made some muffins and thought it didn't cause dumping, but the insulin thing makes sense.  I've stopped eating so much carbs and do feel better.  Makes sense.  Reminds me to re-educate myself on my diet needs now.

thanks, Sheryl
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