After nearly four weeks of eating primal, I had a bad hypoglycemic incident yesterday. I've never had one before, and I'm not (and never have been) diabetic. But after a day of not so many calories following a few nights of heavy-ish drinking (I was at a conference) I got to the airport and was nauseous, dizzy, light headed and certain I was about to black out. Took care of it with a bottle of apple juice over the course of about an hour, and then after ate some cheese and crackers (I was on a plane, and it didn't seem to make sense to be picky). So, clearly the drinking is the main culprit. But I've never had this experience before, and since the drinking is certainly not new, it seems the diet is a factor. Has anyone else experienced this? Do I need to eat some fruit to get more sugar? (I've been avoiding fruit for weight loss) Do I need to be counting calories? I hadn't eaten much that day, but I wasn't hungry. Clearly cutting way back on the wine is the first thing I'll be doing.
The description you give certainly matches what could be a low blood sugar episode. I recently found out that I may have reactive hypoglycemia (i.e. I get low blood sugar in reaction to certain foods rather than due to not eating in general) and I'm waiting to find out when I need to go for blood tests etc. When I have episodes when (I now suspect) my blood sugar is low I feel similar to how you have described.
I would guess that the reduced calories (i.e. your body couldn't get much glucose from not much ingested food) coupled with the alcohol left your body with a bit of a deficit. I don't know the science behind it but alcohol can be bad for people with hypoclycemia so it definitely has an effect on the blood sugar. Ever since I started drinking I've known that I can't have too much - I always put it down to having a slight intolerance and I've never been able to understand how people could get drunk and enjoy it, I always just feel ill!
While diabetics get hypoglycemia, in them it is caused by taking too much insulin versus their sugar intake. Low blood sugar when you are not diabetic, from what I can understand, is caused by either too much natural insulin or by using more glucose from the blood stream than you can replace.
In this case, given you don't think you have experienced this before I would suggest that you didn't eat enough and then had a big night out so you just used more than you could replace rather than that you have a problem with low blood sugar in general Once I found out about hypoglycemia I was able to look back over many years and spot things that I'm now sure were related to it. I've always suffered for lightheadedness, severe tiredness and other symptoms but not known that they indicated something. I have no idea if I am very or only slightly hypoglycemic though so I'm not sure if I'm a good guide from that point of view. Have a look at some websites and see if anything rings bells for you - it may be that this is just the most severe reaction you have had and that you get less severe symptoms which you have always written off as normal for you.
If you are worried about you blood sugar dropping in reaction to what you are eating, I would say stay away from sugar and try to keep your blood sugar as level as possible as that has worked for me. This means watching your fruit intake (particularly sugary fruits) as well as refined carbs and looking at the labels on everything you buy which is not raw, unprocessed ingredients to avoid them. There are loads of websites with various diets for hypoglycemics but having read a lot, the ones written by people who are hypoglyemic (and therefore have first hand experience) tend to boil down to something very similar to primal so that is what I am sticking to for now. It immediately made a huge difference when I switched so I'm going with it at the moment regardless of what "official" advice I may get if the blood tests come back positive.
I wouldn't worry about your calorie count - just eat healthily, make sure you are eating when you are hungry and stay away the heavy drinking If anything, when I think my levels are dropping a bit I have found that if I increase the fat content of my next meal (and fast-track that meal or have a snack if I feel I need it) that seems to stop it in its tracks. That's nothing scientific at all though - just my personal observation of myself.
Hope that helps a bit