Saturday, March 21, 2009

Tired after eating, part 2

There is one post on a blog called "Blogging in Paris" that has more than 100 comments regarding "tired after eating." Reading those comments has been very helpful for me, and I recently posted the following long-winded comment:

I am beginning to speculate that, at least in my case, getting exhausted after eating might be largely psychosomatic. After trying to "figure it out" for years, I have noticed that I do not get as tired if I do something fun and/or stimulating after eating. On the other hand, if I go to a boring class or try to study uninteresting material after a meal, I get an intense urge to put my head down and close my eyes. And, in fact, that is what I end up doing on many occasions, much to the chagrin of the professor or the people around me in the library being distracted by my snoring. And, like others have described, I could circumvent the problem either by not eating or by not eating any carbohydrates.

Feeling a little sleepy after eating is actually a normal physiological response. Eating naturally actives your parasympathetic nervous system, which can be functionally described as "rest and digest" (as opposed to your sympathetic nervous system, which is "fight or flight"), and therefore people tend to feel drowsy after a meal. This reaction seems to happen to a substantial portion of the population, as typing in "tired after eating" into Google produces 19,700,000 results. What is perhaps more telling is that many people around the world take naps (e.g. siestas) after meals, although this custom is not typical in the United States because sleep is vacuously associated with laziness.

Notwithstanding the prevalence of this problem, many people who have commented here (myself included) seem to experience postprandial fatigue that is far more severe than the typical drowsiness that the rest of the population deals with. So the question is, why? Well, in my case, I think it might be due to dysthymia or some sort of emotional problem. One day I realized that, even if I somehow found a way to feel alert after eating, I probably wouldn't want to sit down and read some boring textbook or sit in a lecture hall with 300 other people listening to some monotone professor read off of his PowerPoint slides. I also realized that I was enjoying eating way too much. In fact, I didn't really enjoy doing anything other than eating. There were days when I would have a hearty lunch, like a sandwich, side of pasta, and a salad, and then I would eat like 1000 additional calories of packaged cracker and cheese sandwiches when I got back to my room. I absolutely loved carbohydrates and could easily eat half a tray of Fig Newtons, three peanut butter and jelly sandwiches, and so on. Incidentally, eating carbohydrates almost always put me in a "food coma."

Eventually, I noticed that my symptoms (hyperphagia, hypersomnia, feeling of heaviness in the arms and legs, being really sensitive to rejection, loss of interest in virtually everything) were all characteristic of a type of depression called atypical depression. Atypical depression is different from major depression in that vegetative behaviors are exaggerated instead of minimized. People with major depression usually sleep less, eat less, and are anxious, so I guess that's what makes atypical depression so "atypical". So from here, I came up with the following far-fetched and probably wrong explanation (but I'll just mention it for what it's worth). One study from researchers at NIH ("Organization of the stress system and its dysregulation in melancholic and atypical depression: high vs low CRH/NE states") showed that patients with atypical depression have low levels of corticotropin-releleasing hormone, a hypothalamic hormone that stimulates the adrenal glands to secrete glucocorticoids (e.g. cortisol). Such a deficiency could theoretically lead to low cortisol levels, and this could in turn lead to increased insulin sensitivity, since glucocorticoids normally antagonize the effects of insulin. If this were the case, then a person with low cortisol would experience a sudden drop in blood sugar after eating (especially carbohydrates), because insulin's effects would be exaggerated. And this in turn fits with the whole idea of "idiopathic reactive hypoglycemia," a condition in which patients feel tired, irritable, anxious, and/or dizzy after eating. Incidentally, this condition is also associated with emotional problems (see "Suspected postprandial hypoglycemia is associated with beta-adrenergic hypersensitivity and emotional distress") and doesn't seem to have a physiological basis (except in "alimentary reactive hypoglycemia," i.e. dumping syndrome that occurs after gastrectomy or gastric bypass surgery). The paper written by the NIH researchers also said that norepinephrine is somehow affected by low CRH. This suggestion is consistent with the catecholamine hypothesis of affective, which suggests that low catecholamine levels (e.g norepinephrine) are responsible for to mood disorders like depression.

OK, well I don't want this comment to turn into an essay, so here's what I have been doing to fix the tired after eating problem:

- drinking coffee

- always trying to balance carbohydrates with fat and protein

- eating chocolate

- trying to do something else that is enjoyable to relax besides eating

- avoiding the following: Googling "tired after eating" and then wondering if it's being caused by "candidiasis," "mercury toxicity," "fluoride poisoning," "food allergies," "toxic bowel," and so on, and so on...

- similar to the above, not visiting alternative medicine web sites

- doing stretches and deep breathing from time to time

This is just what I have come up with to explain my own particular situation. I would definitely recommend anyone experiencing extreme fatigue to see their doctor to get screened for the usual culprits (e.g. anemia, thyroid disease, diabetes). But, if the lab tests all come back normal, then I would definitely consider emotional problems as the cause of postprandial fatigue. I actually had a doctor tell me a few years ago that my GI problems were being caused by depression. I proceeded to visit several other doctors who looked for some physiological explanation of my non-specific symptoms and came up with nothing. I thought that the first doctor I saw was just being lazy at the time and was making up a diagnosis because he didn't know anything, but now I think that he was right the whole time. It's been difficult to admit to myself that my symptoms probably stem from psychological problems, but now that I've written what is now an essay, it seems like that's a reasonable explanation. And I am willing to bet that at least some people experiencing fatigue after eating also have some sort of affective issue.


At some point I would like to clean this up a bit and appropriately cite references. But I think that what I described in that post is a possible explanation for getting tired after eating. If anyone has any comments, I would love to hear them!