I don't consider it an issue, unless you find it happening a lot and are uncomfortable with it. I think it really is just a nap gone wrong (or more accurately, a nap you didn't get to finish).
Originally Posted by starfishkitty
I'm not sure if it's true or not that it's not good to fall asleep after eating, but my old fashioned grandmother swears that's so!
It's a common bit of cultural "wisdom," but there are just as many cultures who believe it's healthiest to sleep after eating and unhealthy to skip the nap (it's part of the rational for the siesta - that and the heat of the mid-day sun).
Meals (high carb or not) can cause sleepiness or fatigue, because quite a bit of blood flow is diverted to the digestive tract after eating (and away from the brain and extremities). Activity, because it draws the blood away from the digestive tract, slows digestion, so the instinct to rest after eating is normal (most animals do it).
If the meal is larger (or for some other reason a greater challenge to digest) than your typical meal - or if you're also tired from another reason (maybe not getting as deep a sleep the previous night or any of a thousand other reasons), you may feel more tired than typical (creating that "hard to resist a nap" feeling).
The disorientation on waking is a different issue entirely. Feeling disoriented and uncomfortable when waking, isn't characteristic of deep sleep, it's actually characteristic of the opposite. The sleep cycle generally takes on average 90 to 100 minutes (the stages will get longer, the longer you sleep). There are 5 stages of sleep, and the last stage of sleep is the deepest. If you wake naturally (after you're ending your 5th stage), you're more likely to wake rested than if you are woken earlier.
If you remember dreaming, you probable ended sleep "early." Like many people with fibromyalgia, I have a hard time reaching the deepest stages of sleep (the restorative stages), which many doctors feels is actually the underlying cause of many cases of fibromyalgia (Although I studied sleep in graduate school, I've studied sleep and sleep disorders a lot more since I was diagnosed with fibromyalgia and two seperate sleep disorders, but that's a long and different story).
To get back to the original topic though - it's entirely normal to feel tired after eating, and a nap isn't unhealthy or harmful (it actually may aid digestion), but if you don't have time to get through a full sleep cycle - or if you're woken from it before completing the cycle, you may not wake as rested as you'd like.